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The inadvisability of charging LiFePO4 batteries below 32F/0C (akabelow freezing)



 
 
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  #31  
Old March 23rd 18, 03:21 AM posted to rec.aviation.soaring
Andrzej Kobus
external usenet poster
 
Posts: 585
Default The inadvisability of charging LiFePO4 batteries below 32F/0C(aka below freezing)

On Thursday, March 22, 2018 at 10:04:02 PM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 3:37:31 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 1:09:13 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 5:00:32 PM UTC-7, Andrzej Kobus wrote:
On Wednesday, March 21, 2018 at 7:18:52 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 12:12:31 PM UTC-7, Tango Eight wrote:
On Wednesday, March 21, 2018 at 2:15:26 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 10:22:48 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
While I usually don't disagree with you, if you READ what Tango8 posted, he is saying the same thing as you.
"Lithium in the name does make it the same", as I read it.

Your thoughts?!

Yes, I am going from early (late '70's NiCads to more modern LiFe or LiOn/LiPo) rechargeables including LA of various flavors.

I have a bunch of cash tied up in chargers for various battery chemistries, mostly in RC use, but also for my main income.

Hey, hey find an issue with my read of Tango8's post, I am willing to learn, but I believe you read it wrong.

I don't believe it is dangerous to refer to Lithium Ion batteries as Lithium Ion batteries. But in T8s post he said it was, and further said '"LiIon" vs "LiPo" vs "LFP"' which implies that Lithium Ion batteries are a type of Lithium Ion batteries. The semantics matter. Had he quoted my post in context (the complete sentence was "If it has lithium in it, it is a Lithium Ion battery, but beyond that there are big differences in chemistry and mechanical construction.") perhaps he would have not thought what I said dangerous. You cannot charge a LiIon battery differently than an LFP, because an LFP IS a LiIon battery. LiIon includes all the different chemistries but the members of that group differ in their associated charge requirements.

It is much better to use language precisely when the result of a misunderstanding can be an explosion and fire. If you specify an LFP charger you should get want you want. If you specify a LiIon charger you have no idea what you are going to get.

Jon, you're clearly unfamiliar with the terminology as it is used out in the real world. There are many (millions) multi-mode chargers out there that use the terms as I have used them, "LiIon, LiPo, LFP". Semantics matter? Sure. Safety based on correctly matching charging cycles to chemistry matters more.

Here's a link to the instructions for a commercial charger that illustrates what I am talking about. They use the terms LiIo, and LiFe instead of LiIon and LFP.

http://www.ircha.org/sites/default/f...ntam%20BC6.pdf

I am well aware of the loose and incorrect usage of terms, and it is what I am arguing against as potentially dangerous. As I said in my second post in this thread, "unfortunately there is confusion". What exactly is the voltage and chemistry of a LiIo, or LiIon, or Lithium battery? In the real world, Google "lithium ion battery" will correctly return hits on all types, not just lithium polymer, with recommended charging voltage of between 3.2 and several hundred volts. Even in the last few of posts we have the conflation of several chemistries. The news media is horribly guilty of this, from them we know that lithium batteries cause cars and aircraft to catch fire and burn, and hoverboards to self immolate. I have been told on this very forum that lithium ion batteries should not be used in gliders because they cause Boeing 787s and Chevy Volts and Samsung S7s to burn - never mind that those batteries are quite different than the ones we use.

If I have a charger than says "LiIo" or "lithium" charger on it, that tells me little or nothing about what battery I can charge with it. This is my point. "Correctly matching charing cycles to chemistry" can only be done if the specific chemistry or voltages required are stated. "Lithium ion" is the term used for the collection of chemistries using lithium anodes or cathodes. If that is not the correct term, then what is? And why is it "dangerous" to use the correct term? And if speaking in a context where the specific chemistry dangerously matters, shouldn't the specific term be used, rather than the general?

John, I am sorry, but aren't you the one who uses unapproved, for starting, LiFePo4 batteries in your ASH-26E for engine starting? I am surprised you seem to lecture others while you do questionable things yourself, just saying.

Andrzej, the Schleicher maintenance manual (which specifies SLA batteries for both engine AND avionics) was written in 1995, and is not likely to consider a battery technology invented in 1996. Anyone flying an ASW 27 or 29 should similarly not use an LFP battery for avionics as they are not an approved type. Yet nearly every glider supply outlet sells them for this purpose, and I note that Schleicher ships LFP batteries for both start and avionics in many of their current gliders.

I'm not lecturing (or even recommending) people to use or not use anything. I educated myself on what was required and acted accordingly based on facts, not questions. I AM asking that they use precise language, where precise language is important. Schleicher does not say "use a lead battery", rather they say "use a maintenance free lead-dry-gel battery" - because installing a flooded lead acid battery on its side near your butt is a bad idea. Even then they are imprecise - the battery they call out is an AGM, not a gel and these have different charge requirements. The terminology matters.


John, the battery you are using was not designed for starting purposes. The CTC LFP128198 is only rated for 100 Amps for 30 sec, not as you stated in another thread at 160 Amps for 30 sec. 160 Amp is the rating of the protection circuit with is not enough in this application (http://sepbatteries..com/media/add_info/LFP128198.pdf). You are simply operating this battery at very thin safety margins. I am surprised that this does not bother you. A more appropriate solution would be EarthX battery specifically build for experimental aircraft as an engine starting battery, http://earthxbatteries..com/product-...ental-aircraft
Yes, it is very expensive but your life is priceless, or a better solution; or better yet the Odyssey PC680 Battery


Andrzej, I appreciate your concern for me. I did misstate the spec, it is 100 amps for 30 seconds. (In a conversation with the designer, he said 150 amps for several seconds). Fortunately that is more than adequate to start the engine (I have measured the starting current, typically 80 amps for 3 seconds, and it has been routinely starting my engine for 3 years now). CTC in their marketing literature has stated that the battery is designed for engine start use. But perhaps the biggest problem I have is the characterization that this is a safety issue. It is not a safety issue. In the worst case, the battery will go into overcurrent protection and disconnect. If you are flying a motorglider in any situation where a dead starting battery is a safety issue, you need to review your flying practices. Even the ASH flight manual warns against this in section 4.5.1, "One must always be prepared for the possibility that the power plant will fail to deliver the hoped for propulsion." I love that sentence.

Second, you apparently have not looked into the specifications of the SLA battery Schleicher specifies. It is the Yuasa 18-12, the data sheet spec's a maximum discharge of 112 amps. Are they "simply operating this battery at very thin safety margins"? It is much more likely to reach that maximum than the CTC, because the internal resistance is much higher and the starter voltage lower. It is not advertised or spec'd for engine start use. The Odyssey PC680 is a TPT starved electrolyte battery and does not meet Schleicher's specification of a "lead-dry-gel battery". These batteries ARE a safety issue as they have no internal overcurrent protection and will literally melt down in a fault. There is no fault protection in the starting circuit of an ASH26.

The earthX battery does not fit in the hole. There are other LFP motorcycle "starter" batteries that will, but most do not have the same true AH capacity.

You may use whatever battery you like, but don't worry about me - I'm perfectly safe.


John, sorry to disappoint you, Schleicher does not install "lead-dry-gel batteries" in their gliders. They install AGM batteries with maximum discharge current for 5 seconds of 330 Amps. Try that with your battery. Relying on Chinese mass produced circuits for your safety is not something that I would be willing to do at these current levels. Odyssey PC680 is an AGM battery, which is the same type as the one installed by Schleicher.
  #32  
Old March 23rd 18, 04:59 AM posted to rec.aviation.soaring
2G
external usenet poster
 
Posts: 1,439
Default The inadvisability of charging LiFePO4 batteries below 32F/0C(aka below freezing)

On Thursday, March 22, 2018 at 7:21:37 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 10:04:02 PM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 3:37:31 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 1:09:13 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 5:00:32 PM UTC-7, Andrzej Kobus wrote:
On Wednesday, March 21, 2018 at 7:18:52 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 12:12:31 PM UTC-7, Tango Eight wrote:
On Wednesday, March 21, 2018 at 2:15:26 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 10:22:48 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
While I usually don't disagree with you, if you READ what Tango8 posted, he is saying the same thing as you.
"Lithium in the name does make it the same", as I read it..

Your thoughts?!

Yes, I am going from early (late '70's NiCads to more modern LiFe or LiOn/LiPo) rechargeables including LA of various flavors.

I have a bunch of cash tied up in chargers for various battery chemistries, mostly in RC use, but also for my main income.

Hey, hey find an issue with my read of Tango8's post, I am willing to learn, but I believe you read it wrong.

I don't believe it is dangerous to refer to Lithium Ion batteries as Lithium Ion batteries. But in T8s post he said it was, and further said '"LiIon" vs "LiPo" vs "LFP"' which implies that Lithium Ion batteries are a type of Lithium Ion batteries. The semantics matter. Had he quoted my post in context (the complete sentence was "If it has lithium in it, it is a Lithium Ion battery, but beyond that there are big differences in chemistry and mechanical construction.") perhaps he would have not thought what I said dangerous. You cannot charge a LiIon battery differently than an LFP, because an LFP IS a LiIon battery. LiIon includes all the different chemistries but the members of that group differ in their associated charge requirements.

It is much better to use language precisely when the result of a misunderstanding can be an explosion and fire. If you specify an LFP charger you should get want you want. If you specify a LiIon charger you have no idea what you are going to get.

Jon, you're clearly unfamiliar with the terminology as it is used out in the real world. There are many (millions) multi-mode chargers out there that use the terms as I have used them, "LiIon, LiPo, LFP". Semantics matter? Sure. Safety based on correctly matching charging cycles to chemistry matters more.

Here's a link to the instructions for a commercial charger that illustrates what I am talking about. They use the terms LiIo, and LiFe instead of LiIon and LFP.

http://www.ircha.org/sites/default/f...ntam%20BC6.pdf

I am well aware of the loose and incorrect usage of terms, and it is what I am arguing against as potentially dangerous. As I said in my second post in this thread, "unfortunately there is confusion". What exactly is the voltage and chemistry of a LiIo, or LiIon, or Lithium battery? In the real world, Google "lithium ion battery" will correctly return hits on all types, not just lithium polymer, with recommended charging voltage of between 3.2 and several hundred volts. Even in the last few of posts we have the conflation of several chemistries. The news media is horribly guilty of this, from them we know that lithium batteries cause cars and aircraft to catch fire and burn, and hoverboards to self immolate. I have been told on this very forum that lithium ion batteries should not be used in gliders because they cause Boeing 787s and Chevy Volts and Samsung S7s to burn - never mind that those batteries are quite different than the ones we use.

If I have a charger than says "LiIo" or "lithium" charger on it, that tells me little or nothing about what battery I can charge with it. This is my point. "Correctly matching charing cycles to chemistry" can only be done if the specific chemistry or voltages required are stated. "Lithium ion" is the term used for the collection of chemistries using lithium anodes or cathodes. If that is not the correct term, then what is? And why is it "dangerous" to use the correct term? And if speaking in a context where the specific chemistry dangerously matters, shouldn't the specific term be used, rather than the general?

John, I am sorry, but aren't you the one who uses unapproved, for starting, LiFePo4 batteries in your ASH-26E for engine starting? I am surprised you seem to lecture others while you do questionable things yourself, just saying.

Andrzej, the Schleicher maintenance manual (which specifies SLA batteries for both engine AND avionics) was written in 1995, and is not likely to consider a battery technology invented in 1996. Anyone flying an ASW 27 or 29 should similarly not use an LFP battery for avionics as they are not an approved type. Yet nearly every glider supply outlet sells them for this purpose, and I note that Schleicher ships LFP batteries for both start and avionics in many of their current gliders.

I'm not lecturing (or even recommending) people to use or not use anything. I educated myself on what was required and acted accordingly based on facts, not questions. I AM asking that they use precise language, where precise language is important. Schleicher does not say "use a lead battery", rather they say "use a maintenance free lead-dry-gel battery" - because installing a flooded lead acid battery on its side near your butt is a bad idea. Even then they are imprecise - the battery they call out is an AGM, not a gel and these have different charge requirements. The terminology matters.

John, the battery you are using was not designed for starting purposes. The CTC LFP128198 is only rated for 100 Amps for 30 sec, not as you stated in another thread at 160 Amps for 30 sec. 160 Amp is the rating of the protection circuit with is not enough in this application (http://sepbatteries.com/media/add_info/LFP128198.pdf). You are simply operating this battery at very thin safety margins. I am surprised that this does not bother you.. A more appropriate solution would be EarthX battery specifically build for experimental aircraft as an engine starting battery, http://earthxbatteries.com/product-c...ental-aircraft
Yes, it is very expensive but your life is priceless, or a better solution; or better yet the Odyssey PC680 Battery


Andrzej, I appreciate your concern for me. I did misstate the spec, it is 100 amps for 30 seconds. (In a conversation with the designer, he said 150 amps for several seconds). Fortunately that is more than adequate to start the engine (I have measured the starting current, typically 80 amps for 3 seconds, and it has been routinely starting my engine for 3 years now). CTC in their marketing literature has stated that the battery is designed for engine start use. But perhaps the biggest problem I have is the characterization that this is a safety issue. It is not a safety issue. In the worst case, the battery will go into overcurrent protection and disconnect. If you are flying a motorglider in any situation where a dead starting battery is a safety issue, you need to review your flying practices. Even the ASH flight manual warns against this in section 4.5.1, "One must always be prepared for the possibility that the power plant will fail to deliver the hoped for propulsion." I love that sentence.

Second, you apparently have not looked into the specifications of the SLA battery Schleicher specifies. It is the Yuasa 18-12, the data sheet spec's a maximum discharge of 112 amps. Are they "simply operating this battery at very thin safety margins"? It is much more likely to reach that maximum than the CTC, because the internal resistance is much higher and the starter voltage lower. It is not advertised or spec'd for engine start use. The Odyssey PC680 is a TPT starved electrolyte battery and does not meet Schleicher's specification of a "lead-dry-gel battery". These batteries ARE a safety issue as they have no internal overcurrent protection and will literally melt down in a fault. There is no fault protection in the starting circuit of an ASH26.

The earthX battery does not fit in the hole. There are other LFP motorcycle "starter" batteries that will, but most do not have the same true AH capacity.

You may use whatever battery you like, but don't worry about me - I'm perfectly safe.


John, sorry to disappoint you, Schleicher does not install "lead-dry-gel batteries" in their gliders. They install AGM batteries with maximum discharge current for 5 seconds of 330 Amps. Try that with your battery. Relying on Chinese mass produced circuits for your safety is not something that I would be willing to do at these current levels. Odyssey PC680 is an AGM battery, which is the same type as the one installed by Schleicher.


The Maintenance Manual for the 26e says "YUASA Type NPG 12-18 12 Volt 17.2 Ah, or similar." The NPG is definitely an AGM, not a gel-cell. Basically, you can't use a wet-cell for obvious reasons.

Also, the battery must be able to deliver the inrush current of the starter, which is typically 50% more than the current once running. This is essential because the running starter generates a back EMF that reduces the current draw - without it running you don't get the back EMF.

Tom
  #33  
Old March 23rd 18, 06:02 AM posted to rec.aviation.soaring
jfitch
external usenet poster
 
Posts: 1,134
Default The inadvisability of charging LiFePO4 batteries below 32F/0C(aka below freezing)

On Thursday, March 22, 2018 at 7:21:37 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 10:04:02 PM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 3:37:31 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 1:09:13 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 5:00:32 PM UTC-7, Andrzej Kobus wrote:
On Wednesday, March 21, 2018 at 7:18:52 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 12:12:31 PM UTC-7, Tango Eight wrote:
On Wednesday, March 21, 2018 at 2:15:26 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 10:22:48 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
While I usually don't disagree with you, if you READ what Tango8 posted, he is saying the same thing as you.
"Lithium in the name does make it the same", as I read it..

Your thoughts?!

Yes, I am going from early (late '70's NiCads to more modern LiFe or LiOn/LiPo) rechargeables including LA of various flavors.

I have a bunch of cash tied up in chargers for various battery chemistries, mostly in RC use, but also for my main income.

Hey, hey find an issue with my read of Tango8's post, I am willing to learn, but I believe you read it wrong.

I don't believe it is dangerous to refer to Lithium Ion batteries as Lithium Ion batteries. But in T8s post he said it was, and further said '"LiIon" vs "LiPo" vs "LFP"' which implies that Lithium Ion batteries are a type of Lithium Ion batteries. The semantics matter. Had he quoted my post in context (the complete sentence was "If it has lithium in it, it is a Lithium Ion battery, but beyond that there are big differences in chemistry and mechanical construction.") perhaps he would have not thought what I said dangerous. You cannot charge a LiIon battery differently than an LFP, because an LFP IS a LiIon battery. LiIon includes all the different chemistries but the members of that group differ in their associated charge requirements.

It is much better to use language precisely when the result of a misunderstanding can be an explosion and fire. If you specify an LFP charger you should get want you want. If you specify a LiIon charger you have no idea what you are going to get.

Jon, you're clearly unfamiliar with the terminology as it is used out in the real world. There are many (millions) multi-mode chargers out there that use the terms as I have used them, "LiIon, LiPo, LFP". Semantics matter? Sure. Safety based on correctly matching charging cycles to chemistry matters more.

Here's a link to the instructions for a commercial charger that illustrates what I am talking about. They use the terms LiIo, and LiFe instead of LiIon and LFP.

http://www.ircha.org/sites/default/f...ntam%20BC6.pdf

I am well aware of the loose and incorrect usage of terms, and it is what I am arguing against as potentially dangerous. As I said in my second post in this thread, "unfortunately there is confusion". What exactly is the voltage and chemistry of a LiIo, or LiIon, or Lithium battery? In the real world, Google "lithium ion battery" will correctly return hits on all types, not just lithium polymer, with recommended charging voltage of between 3.2 and several hundred volts. Even in the last few of posts we have the conflation of several chemistries. The news media is horribly guilty of this, from them we know that lithium batteries cause cars and aircraft to catch fire and burn, and hoverboards to self immolate. I have been told on this very forum that lithium ion batteries should not be used in gliders because they cause Boeing 787s and Chevy Volts and Samsung S7s to burn - never mind that those batteries are quite different than the ones we use.

If I have a charger than says "LiIo" or "lithium" charger on it, that tells me little or nothing about what battery I can charge with it. This is my point. "Correctly matching charing cycles to chemistry" can only be done if the specific chemistry or voltages required are stated. "Lithium ion" is the term used for the collection of chemistries using lithium anodes or cathodes. If that is not the correct term, then what is? And why is it "dangerous" to use the correct term? And if speaking in a context where the specific chemistry dangerously matters, shouldn't the specific term be used, rather than the general?

John, I am sorry, but aren't you the one who uses unapproved, for starting, LiFePo4 batteries in your ASH-26E for engine starting? I am surprised you seem to lecture others while you do questionable things yourself, just saying.

Andrzej, the Schleicher maintenance manual (which specifies SLA batteries for both engine AND avionics) was written in 1995, and is not likely to consider a battery technology invented in 1996. Anyone flying an ASW 27 or 29 should similarly not use an LFP battery for avionics as they are not an approved type. Yet nearly every glider supply outlet sells them for this purpose, and I note that Schleicher ships LFP batteries for both start and avionics in many of their current gliders.

I'm not lecturing (or even recommending) people to use or not use anything. I educated myself on what was required and acted accordingly based on facts, not questions. I AM asking that they use precise language, where precise language is important. Schleicher does not say "use a lead battery", rather they say "use a maintenance free lead-dry-gel battery" - because installing a flooded lead acid battery on its side near your butt is a bad idea. Even then they are imprecise - the battery they call out is an AGM, not a gel and these have different charge requirements. The terminology matters.

John, the battery you are using was not designed for starting purposes. The CTC LFP128198 is only rated for 100 Amps for 30 sec, not as you stated in another thread at 160 Amps for 30 sec. 160 Amp is the rating of the protection circuit with is not enough in this application (http://sepbatteries.com/media/add_info/LFP128198.pdf). You are simply operating this battery at very thin safety margins. I am surprised that this does not bother you.. A more appropriate solution would be EarthX battery specifically build for experimental aircraft as an engine starting battery, http://earthxbatteries.com/product-c...ental-aircraft
Yes, it is very expensive but your life is priceless, or a better solution; or better yet the Odyssey PC680 Battery


Andrzej, I appreciate your concern for me. I did misstate the spec, it is 100 amps for 30 seconds. (In a conversation with the designer, he said 150 amps for several seconds). Fortunately that is more than adequate to start the engine (I have measured the starting current, typically 80 amps for 3 seconds, and it has been routinely starting my engine for 3 years now). CTC in their marketing literature has stated that the battery is designed for engine start use. But perhaps the biggest problem I have is the characterization that this is a safety issue. It is not a safety issue. In the worst case, the battery will go into overcurrent protection and disconnect. If you are flying a motorglider in any situation where a dead starting battery is a safety issue, you need to review your flying practices. Even the ASH flight manual warns against this in section 4.5.1, "One must always be prepared for the possibility that the power plant will fail to deliver the hoped for propulsion." I love that sentence.

Second, you apparently have not looked into the specifications of the SLA battery Schleicher specifies. It is the Yuasa 18-12, the data sheet spec's a maximum discharge of 112 amps. Are they "simply operating this battery at very thin safety margins"? It is much more likely to reach that maximum than the CTC, because the internal resistance is much higher and the starter voltage lower. It is not advertised or spec'd for engine start use. The Odyssey PC680 is a TPT starved electrolyte battery and does not meet Schleicher's specification of a "lead-dry-gel battery". These batteries ARE a safety issue as they have no internal overcurrent protection and will literally melt down in a fault. There is no fault protection in the starting circuit of an ASH26.

The earthX battery does not fit in the hole. There are other LFP motorcycle "starter" batteries that will, but most do not have the same true AH capacity.

You may use whatever battery you like, but don't worry about me - I'm perfectly safe.


John, sorry to disappoint you, Schleicher does not install "lead-dry-gel batteries" in their gliders. They install AGM batteries with maximum discharge current for 5 seconds of 330 Amps. Try that with your battery. Relying on Chinese mass produced circuits for your safety is not something that I would be willing to do at these current levels. Odyssey PC680 is an AGM battery, which is the same type as the one installed by Schleicher.


The Schleicher spec is "lead-dry-gel batteries, quoted directly from the AS maintenance manual, section 2.8. I don't make this stuff up. That is not an AGM battery. They currently ship LiFePo4 batteries in a new glider. I'd like to know what you are going to do with 330 amps for 5 seconds? Arc weld with it? The starter does not draw anywhere near that, even with the propeller locked. The wires are only #6, and before than 6x#14. The rated carrying capacity of #6 is 102 amps. You will fry the wires. You will fry the switch and the solenoid and connectors. The starter will burn to a crisp. I do not wish to try that with any battery in my glider, it is exactly why I prefer the safety of the LFP with a disconnect, as opposed to a PC680 which can short circuit far more than that. I don't want to start a fire, I just want to start my engine. This isn't a "my battery is bigger than your battery" situation.

The Yuasa and Panasonic AGM batteries most are using are likely made in China, as are at least half of the electronics in your glider. The main tire and tube are made in Brazil or China, I'm a lot more concerned about that than the battery. We risk our lives everyday on Chinese mass produced circuits - where do you think the circuits in your car's ABS and air bag system come from?
  #34  
Old March 23rd 18, 06:17 AM posted to rec.aviation.soaring
jfitch
external usenet poster
 
Posts: 1,134
Default The inadvisability of charging LiFePO4 batteries below 32F/0C(aka below freezing)

On Thursday, March 22, 2018 at 8:59:50 PM UTC-7, 2G wrote:
On Thursday, March 22, 2018 at 7:21:37 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 10:04:02 PM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 3:37:31 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 1:09:13 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 5:00:32 PM UTC-7, Andrzej Kobus wrote:
On Wednesday, March 21, 2018 at 7:18:52 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 12:12:31 PM UTC-7, Tango Eight wrote:
On Wednesday, March 21, 2018 at 2:15:26 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 10:22:48 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
While I usually don't disagree with you, if you READ what Tango8 posted, he is saying the same thing as you.
"Lithium in the name does make it the same", as I read it.

Your thoughts?!

Yes, I am going from early (late '70's NiCads to more modern LiFe or LiOn/LiPo) rechargeables including LA of various flavors.

I have a bunch of cash tied up in chargers for various battery chemistries, mostly in RC use, but also for my main income.

Hey, hey find an issue with my read of Tango8's post, I am willing to learn, but I believe you read it wrong.

I don't believe it is dangerous to refer to Lithium Ion batteries as Lithium Ion batteries. But in T8s post he said it was, and further said '"LiIon" vs "LiPo" vs "LFP"' which implies that Lithium Ion batteries are a type of Lithium Ion batteries. The semantics matter. Had he quoted my post in context (the complete sentence was "If it has lithium in it, it is a Lithium Ion battery, but beyond that there are big differences in chemistry and mechanical construction.") perhaps he would have not thought what I said dangerous. You cannot charge a LiIon battery differently than an LFP, because an LFP IS a LiIon battery. LiIon includes all the different chemistries but the members of that group differ in their associated charge requirements.

It is much better to use language precisely when the result of a misunderstanding can be an explosion and fire. If you specify an LFP charger you should get want you want. If you specify a LiIon charger you have no idea what you are going to get.

Jon, you're clearly unfamiliar with the terminology as it is used out in the real world. There are many (millions) multi-mode chargers out there that use the terms as I have used them, "LiIon, LiPo, LFP". Semantics matter? Sure. Safety based on correctly matching charging cycles to chemistry matters more.

Here's a link to the instructions for a commercial charger that illustrates what I am talking about. They use the terms LiIo, and LiFe instead of LiIon and LFP.

http://www.ircha.org/sites/default/f...ntam%20BC6.pdf

I am well aware of the loose and incorrect usage of terms, and it is what I am arguing against as potentially dangerous. As I said in my second post in this thread, "unfortunately there is confusion". What exactly is the voltage and chemistry of a LiIo, or LiIon, or Lithium battery? In the real world, Google "lithium ion battery" will correctly return hits on all types, not just lithium polymer, with recommended charging voltage of between 3.2 and several hundred volts. Even in the last few of posts we have the conflation of several chemistries. The news media is horribly guilty of this, from them we know that lithium batteries cause cars and aircraft to catch fire and burn, and hoverboards to self immolate. I have been told on this very forum that lithium ion batteries should not be used in gliders because they cause Boeing 787s and Chevy Volts and Samsung S7s to burn - never mind that those batteries are quite different than the ones we use.

If I have a charger than says "LiIo" or "lithium" charger on it, that tells me little or nothing about what battery I can charge with it.. This is my point. "Correctly matching charing cycles to chemistry" can only be done if the specific chemistry or voltages required are stated. "Lithium ion" is the term used for the collection of chemistries using lithium anodes or cathodes. If that is not the correct term, then what is? And why is it "dangerous" to use the correct term? And if speaking in a context where the specific chemistry dangerously matters, shouldn't the specific term be used, rather than the general?

John, I am sorry, but aren't you the one who uses unapproved, for starting, LiFePo4 batteries in your ASH-26E for engine starting? I am surprised you seem to lecture others while you do questionable things yourself, just saying.

Andrzej, the Schleicher maintenance manual (which specifies SLA batteries for both engine AND avionics) was written in 1995, and is not likely to consider a battery technology invented in 1996. Anyone flying an ASW 27 or 29 should similarly not use an LFP battery for avionics as they are not an approved type. Yet nearly every glider supply outlet sells them for this purpose, and I note that Schleicher ships LFP batteries for both start and avionics in many of their current gliders.

I'm not lecturing (or even recommending) people to use or not use anything. I educated myself on what was required and acted accordingly based on facts, not questions. I AM asking that they use precise language, where precise language is important. Schleicher does not say "use a lead battery", rather they say "use a maintenance free lead-dry-gel battery" - because installing a flooded lead acid battery on its side near your butt is a bad idea. Even then they are imprecise - the battery they call out is an AGM, not a gel and these have different charge requirements. The terminology matters.

John, the battery you are using was not designed for starting purposes. The CTC LFP128198 is only rated for 100 Amps for 30 sec, not as you stated in another thread at 160 Amps for 30 sec. 160 Amp is the rating of the protection circuit with is not enough in this application (http://sepbatteries.com/media/add_info/LFP128198.pdf). You are simply operating this battery at very thin safety margins. I am surprised that this does not bother you. A more appropriate solution would be EarthX battery specifically build for experimental aircraft as an engine starting battery, http://earthxbatteries.com/product-c...ental-aircraft
Yes, it is very expensive but your life is priceless, or a better solution; or better yet the Odyssey PC680 Battery

Andrzej, I appreciate your concern for me. I did misstate the spec, it is 100 amps for 30 seconds. (In a conversation with the designer, he said 150 amps for several seconds). Fortunately that is more than adequate to start the engine (I have measured the starting current, typically 80 amps for 3 seconds, and it has been routinely starting my engine for 3 years now). CTC in their marketing literature has stated that the battery is designed for engine start use. But perhaps the biggest problem I have is the characterization that this is a safety issue. It is not a safety issue. In the worst case, the battery will go into overcurrent protection and disconnect. If you are flying a motorglider in any situation where a dead starting battery is a safety issue, you need to review your flying practices. Even the ASH flight manual warns against this in section 4.5.1, "One must always be prepared for the possibility that the power plant will fail to deliver the hoped for propulsion." I love that sentence.

Second, you apparently have not looked into the specifications of the SLA battery Schleicher specifies. It is the Yuasa 18-12, the data sheet spec's a maximum discharge of 112 amps. Are they "simply operating this battery at very thin safety margins"? It is much more likely to reach that maximum than the CTC, because the internal resistance is much higher and the starter voltage lower. It is not advertised or spec'd for engine start use. The Odyssey PC680 is a TPT starved electrolyte battery and does not meet Schleicher's specification of a "lead-dry-gel battery". These batteries ARE a safety issue as they have no internal overcurrent protection and will literally melt down in a fault. There is no fault protection in the starting circuit of an ASH26.

The earthX battery does not fit in the hole. There are other LFP motorcycle "starter" batteries that will, but most do not have the same true AH capacity.

You may use whatever battery you like, but don't worry about me - I'm perfectly safe.


John, sorry to disappoint you, Schleicher does not install "lead-dry-gel batteries" in their gliders. They install AGM batteries with maximum discharge current for 5 seconds of 330 Amps. Try that with your battery. Relying on Chinese mass produced circuits for your safety is not something that I would be willing to do at these current levels. Odyssey PC680 is an AGM battery, which is the same type as the one installed by Schleicher.


The Maintenance Manual for the 26e says "YUASA Type NPG 12-18 12 Volt 17.2 Ah, or similar." The NPG is definitely an AGM, not a gel-cell. Basically, you can't use a wet-cell for obvious reasons.

Also, the battery must be able to deliver the inrush current of the starter, which is typically 50% more than the current once running. This is essential because the running starter generates a back EMF that reduces the current draw - without it running you don't get the back EMF.

Tom


Right before your quote in the maintenance manual is my quote. A good case in point that precise language is important. They say gel then call out an AGM. A gel would actually not be good with their charge circuit, set too high for a gel but fine for an AGM. Or an LFP.

I'm quite aware of the inrush current, I've measured the current in real time with a 100 KHz bandwidth current probe on a 2 GHz recording oscilloscope.. This is well understood engineering - we don't need to guess and speculate, we can measure.
  #35  
Old March 23rd 18, 11:43 AM posted to rec.aviation.soaring
Andrzej Kobus
external usenet poster
 
Posts: 585
Default The inadvisability of charging LiFePO4 batteries below 32F/0C(aka below freezing)

On Friday, March 23, 2018 at 1:03:01 AM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 7:21:37 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 10:04:02 PM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 3:37:31 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 1:09:13 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 5:00:32 PM UTC-7, Andrzej Kobus wrote:
On Wednesday, March 21, 2018 at 7:18:52 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 12:12:31 PM UTC-7, Tango Eight wrote:
On Wednesday, March 21, 2018 at 2:15:26 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 10:22:48 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
While I usually don't disagree with you, if you READ what Tango8 posted, he is saying the same thing as you.
"Lithium in the name does make it the same", as I read it.

Your thoughts?!

Yes, I am going from early (late '70's NiCads to more modern LiFe or LiOn/LiPo) rechargeables including LA of various flavors.

I have a bunch of cash tied up in chargers for various battery chemistries, mostly in RC use, but also for my main income.

Hey, hey find an issue with my read of Tango8's post, I am willing to learn, but I believe you read it wrong.

I don't believe it is dangerous to refer to Lithium Ion batteries as Lithium Ion batteries. But in T8s post he said it was, and further said '"LiIon" vs "LiPo" vs "LFP"' which implies that Lithium Ion batteries are a type of Lithium Ion batteries. The semantics matter. Had he quoted my post in context (the complete sentence was "If it has lithium in it, it is a Lithium Ion battery, but beyond that there are big differences in chemistry and mechanical construction.") perhaps he would have not thought what I said dangerous. You cannot charge a LiIon battery differently than an LFP, because an LFP IS a LiIon battery. LiIon includes all the different chemistries but the members of that group differ in their associated charge requirements.

It is much better to use language precisely when the result of a misunderstanding can be an explosion and fire. If you specify an LFP charger you should get want you want. If you specify a LiIon charger you have no idea what you are going to get.

Jon, you're clearly unfamiliar with the terminology as it is used out in the real world. There are many (millions) multi-mode chargers out there that use the terms as I have used them, "LiIon, LiPo, LFP". Semantics matter? Sure. Safety based on correctly matching charging cycles to chemistry matters more.

Here's a link to the instructions for a commercial charger that illustrates what I am talking about. They use the terms LiIo, and LiFe instead of LiIon and LFP.

http://www.ircha.org/sites/default/f...ntam%20BC6.pdf

I am well aware of the loose and incorrect usage of terms, and it is what I am arguing against as potentially dangerous. As I said in my second post in this thread, "unfortunately there is confusion". What exactly is the voltage and chemistry of a LiIo, or LiIon, or Lithium battery? In the real world, Google "lithium ion battery" will correctly return hits on all types, not just lithium polymer, with recommended charging voltage of between 3.2 and several hundred volts. Even in the last few of posts we have the conflation of several chemistries. The news media is horribly guilty of this, from them we know that lithium batteries cause cars and aircraft to catch fire and burn, and hoverboards to self immolate. I have been told on this very forum that lithium ion batteries should not be used in gliders because they cause Boeing 787s and Chevy Volts and Samsung S7s to burn - never mind that those batteries are quite different than the ones we use.

If I have a charger than says "LiIo" or "lithium" charger on it, that tells me little or nothing about what battery I can charge with it.. This is my point. "Correctly matching charing cycles to chemistry" can only be done if the specific chemistry or voltages required are stated. "Lithium ion" is the term used for the collection of chemistries using lithium anodes or cathodes. If that is not the correct term, then what is? And why is it "dangerous" to use the correct term? And if speaking in a context where the specific chemistry dangerously matters, shouldn't the specific term be used, rather than the general?

John, I am sorry, but aren't you the one who uses unapproved, for starting, LiFePo4 batteries in your ASH-26E for engine starting? I am surprised you seem to lecture others while you do questionable things yourself, just saying.

Andrzej, the Schleicher maintenance manual (which specifies SLA batteries for both engine AND avionics) was written in 1995, and is not likely to consider a battery technology invented in 1996. Anyone flying an ASW 27 or 29 should similarly not use an LFP battery for avionics as they are not an approved type. Yet nearly every glider supply outlet sells them for this purpose, and I note that Schleicher ships LFP batteries for both start and avionics in many of their current gliders.

I'm not lecturing (or even recommending) people to use or not use anything. I educated myself on what was required and acted accordingly based on facts, not questions. I AM asking that they use precise language, where precise language is important. Schleicher does not say "use a lead battery", rather they say "use a maintenance free lead-dry-gel battery" - because installing a flooded lead acid battery on its side near your butt is a bad idea. Even then they are imprecise - the battery they call out is an AGM, not a gel and these have different charge requirements. The terminology matters.

John, the battery you are using was not designed for starting purposes. The CTC LFP128198 is only rated for 100 Amps for 30 sec, not as you stated in another thread at 160 Amps for 30 sec. 160 Amp is the rating of the protection circuit with is not enough in this application (http://sepbatteries.com/media/add_info/LFP128198.pdf). You are simply operating this battery at very thin safety margins. I am surprised that this does not bother you. A more appropriate solution would be EarthX battery specifically build for experimental aircraft as an engine starting battery, http://earthxbatteries.com/product-c...ental-aircraft
Yes, it is very expensive but your life is priceless, or a better solution; or better yet the Odyssey PC680 Battery

Andrzej, I appreciate your concern for me. I did misstate the spec, it is 100 amps for 30 seconds. (In a conversation with the designer, he said 150 amps for several seconds). Fortunately that is more than adequate to start the engine (I have measured the starting current, typically 80 amps for 3 seconds, and it has been routinely starting my engine for 3 years now). CTC in their marketing literature has stated that the battery is designed for engine start use. But perhaps the biggest problem I have is the characterization that this is a safety issue. It is not a safety issue. In the worst case, the battery will go into overcurrent protection and disconnect. If you are flying a motorglider in any situation where a dead starting battery is a safety issue, you need to review your flying practices. Even the ASH flight manual warns against this in section 4.5.1, "One must always be prepared for the possibility that the power plant will fail to deliver the hoped for propulsion." I love that sentence.

Second, you apparently have not looked into the specifications of the SLA battery Schleicher specifies. It is the Yuasa 18-12, the data sheet spec's a maximum discharge of 112 amps. Are they "simply operating this battery at very thin safety margins"? It is much more likely to reach that maximum than the CTC, because the internal resistance is much higher and the starter voltage lower. It is not advertised or spec'd for engine start use. The Odyssey PC680 is a TPT starved electrolyte battery and does not meet Schleicher's specification of a "lead-dry-gel battery". These batteries ARE a safety issue as they have no internal overcurrent protection and will literally melt down in a fault. There is no fault protection in the starting circuit of an ASH26.

The earthX battery does not fit in the hole. There are other LFP motorcycle "starter" batteries that will, but most do not have the same true AH capacity.

You may use whatever battery you like, but don't worry about me - I'm perfectly safe.


John, sorry to disappoint you, Schleicher does not install "lead-dry-gel batteries" in their gliders. They install AGM batteries with maximum discharge current for 5 seconds of 330 Amps. Try that with your battery. Relying on Chinese mass produced circuits for your safety is not something that I would be willing to do at these current levels. Odyssey PC680 is an AGM battery, which is the same type as the one installed by Schleicher.


The Schleicher spec is "lead-dry-gel batteries, quoted directly from the AS maintenance manual, section 2.8. I don't make this stuff up. That is not an AGM battery. They currently ship LiFePo4 batteries in a new glider. I'd like to know what you are going to do with 330 amps for 5 seconds? Arc weld with it? The starter does not draw anywhere near that, even with the propeller locked. The wires are only #6, and before than 6x#14. The rated carrying capacity of #6 is 102 amps. You will fry the wires. You will fry the switch and the solenoid and connectors. The starter will burn to a crisp. I do not wish to try that with any battery in my glider, it is exactly why I prefer the safety of the LFP with a disconnect, as opposed to a PC680 which can short circuit far more than that. I don't want to start a fire, I just want to start my engine. This isn't a "my battery is bigger than your battery" situation.

The Yuasa and Panasonic AGM batteries most are using are likely made in China, as are at least half of the electronics in your glider. The main tire and tube are made in Brazil or China, I'm a lot more concerned about that than the battery. We risk our lives everyday on Chinese mass produced circuits - where do you think the circuits in your car's ABS and air bag system come from?


John, again not true. Schleicher did not want to install LiFePo4 as a starting battery in my glider. I was told they will not do it for safety reason. The whole point is that you are using your LiFePo4 battery close to its design current output and you are relying on the mass produced Chinese electronics to keep you safe. That might work in a motorcycle but it is not really a good idea in an aircraft. The AGM batteries are also produced in China but they don't rely on a cheap circuit board to function properly.
The circuit in my car does not concern me in this discussion. I am not flying my car. Did you check with FAA in regards to installing LiFePo4 battery in your glider?
  #36  
Old March 23rd 18, 04:48 PM posted to rec.aviation.soaring
jfitch
external usenet poster
 
Posts: 1,134
Default The inadvisability of charging LiFePO4 batteries below 32F/0C(aka below freezing)

On Friday, March 23, 2018 at 3:43:18 AM UTC-7, Andrzej Kobus wrote:
On Friday, March 23, 2018 at 1:03:01 AM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 7:21:37 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 10:04:02 PM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 3:37:31 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 1:09:13 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 5:00:32 PM UTC-7, Andrzej Kobus wrote:
On Wednesday, March 21, 2018 at 7:18:52 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 12:12:31 PM UTC-7, Tango Eight wrote:
On Wednesday, March 21, 2018 at 2:15:26 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 10:22:48 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
While I usually don't disagree with you, if you READ what Tango8 posted, he is saying the same thing as you.
"Lithium in the name does make it the same", as I read it.

Your thoughts?!

Yes, I am going from early (late '70's NiCads to more modern LiFe or LiOn/LiPo) rechargeables including LA of various flavors.

I have a bunch of cash tied up in chargers for various battery chemistries, mostly in RC use, but also for my main income.

Hey, hey find an issue with my read of Tango8's post, I am willing to learn, but I believe you read it wrong.

I don't believe it is dangerous to refer to Lithium Ion batteries as Lithium Ion batteries. But in T8s post he said it was, and further said '"LiIon" vs "LiPo" vs "LFP"' which implies that Lithium Ion batteries are a type of Lithium Ion batteries. The semantics matter. Had he quoted my post in context (the complete sentence was "If it has lithium in it, it is a Lithium Ion battery, but beyond that there are big differences in chemistry and mechanical construction.") perhaps he would have not thought what I said dangerous. You cannot charge a LiIon battery differently than an LFP, because an LFP IS a LiIon battery. LiIon includes all the different chemistries but the members of that group differ in their associated charge requirements.

It is much better to use language precisely when the result of a misunderstanding can be an explosion and fire. If you specify an LFP charger you should get want you want. If you specify a LiIon charger you have no idea what you are going to get.

Jon, you're clearly unfamiliar with the terminology as it is used out in the real world. There are many (millions) multi-mode chargers out there that use the terms as I have used them, "LiIon, LiPo, LFP". Semantics matter? Sure. Safety based on correctly matching charging cycles to chemistry matters more.

Here's a link to the instructions for a commercial charger that illustrates what I am talking about. They use the terms LiIo, and LiFe instead of LiIon and LFP.

http://www.ircha.org/sites/default/f...ntam%20BC6.pdf

I am well aware of the loose and incorrect usage of terms, and it is what I am arguing against as potentially dangerous. As I said in my second post in this thread, "unfortunately there is confusion". What exactly is the voltage and chemistry of a LiIo, or LiIon, or Lithium battery? In the real world, Google "lithium ion battery" will correctly return hits on all types, not just lithium polymer, with recommended charging voltage of between 3.2 and several hundred volts. Even in the last few of posts we have the conflation of several chemistries. The news media is horribly guilty of this, from them we know that lithium batteries cause cars and aircraft to catch fire and burn, and hoverboards to self immolate. I have been told on this very forum that lithium ion batteries should not be used in gliders because they cause Boeing 787s and Chevy Volts and Samsung S7s to burn - never mind that those batteries are quite different than the ones we use.

If I have a charger than says "LiIo" or "lithium" charger on it, that tells me little or nothing about what battery I can charge with it. This is my point. "Correctly matching charing cycles to chemistry" can only be done if the specific chemistry or voltages required are stated. "Lithium ion" is the term used for the collection of chemistries using lithium anodes or cathodes. If that is not the correct term, then what is? And why is it "dangerous" to use the correct term? And if speaking in a context where the specific chemistry dangerously matters, shouldn't the specific term be used, rather than the general?

John, I am sorry, but aren't you the one who uses unapproved, for starting, LiFePo4 batteries in your ASH-26E for engine starting? I am surprised you seem to lecture others while you do questionable things yourself, just saying.

Andrzej, the Schleicher maintenance manual (which specifies SLA batteries for both engine AND avionics) was written in 1995, and is not likely to consider a battery technology invented in 1996. Anyone flying an ASW 27 or 29 should similarly not use an LFP battery for avionics as they are not an approved type. Yet nearly every glider supply outlet sells them for this purpose, and I note that Schleicher ships LFP batteries for both start and avionics in many of their current gliders.

I'm not lecturing (or even recommending) people to use or not use anything. I educated myself on what was required and acted accordingly based on facts, not questions. I AM asking that they use precise language, where precise language is important. Schleicher does not say "use a lead battery", rather they say "use a maintenance free lead-dry-gel battery" - because installing a flooded lead acid battery on its side near your butt is a bad idea. Even then they are imprecise - the battery they call out is an AGM, not a gel and these have different charge requirements. The terminology matters.

John, the battery you are using was not designed for starting purposes. The CTC LFP128198 is only rated for 100 Amps for 30 sec, not as you stated in another thread at 160 Amps for 30 sec. 160 Amp is the rating of the protection circuit with is not enough in this application (http://sepbatteries.com/media/add_info/LFP128198.pdf). You are simply operating this battery at very thin safety margins. I am surprised that this does not bother you. A more appropriate solution would be EarthX battery specifically build for experimental aircraft as an engine starting battery, http://earthxbatteries.com/product-c...ental-aircraft
Yes, it is very expensive but your life is priceless, or a better solution; or better yet the Odyssey PC680 Battery

Andrzej, I appreciate your concern for me. I did misstate the spec, it is 100 amps for 30 seconds. (In a conversation with the designer, he said 150 amps for several seconds). Fortunately that is more than adequate to start the engine (I have measured the starting current, typically 80 amps for 3 seconds, and it has been routinely starting my engine for 3 years now). CTC in their marketing literature has stated that the battery is designed for engine start use. But perhaps the biggest problem I have is the characterization that this is a safety issue. It is not a safety issue. In the worst case, the battery will go into overcurrent protection and disconnect. If you are flying a motorglider in any situation where a dead starting battery is a safety issue, you need to review your flying practices. Even the ASH flight manual warns against this in section 4.5.1, "One must always be prepared for the possibility that the power plant will fail to deliver the hoped for propulsion." I love that sentence.

Second, you apparently have not looked into the specifications of the SLA battery Schleicher specifies. It is the Yuasa 18-12, the data sheet spec's a maximum discharge of 112 amps. Are they "simply operating this battery at very thin safety margins"? It is much more likely to reach that maximum than the CTC, because the internal resistance is much higher and the starter voltage lower. It is not advertised or spec'd for engine start use. The Odyssey PC680 is a TPT starved electrolyte battery and does not meet Schleicher's specification of a "lead-dry-gel battery". These batteries ARE a safety issue as they have no internal overcurrent protection and will literally melt down in a fault. There is no fault protection in the starting circuit of an ASH26.

The earthX battery does not fit in the hole. There are other LFP motorcycle "starter" batteries that will, but most do not have the same true AH capacity.

You may use whatever battery you like, but don't worry about me - I'm perfectly safe.

John, sorry to disappoint you, Schleicher does not install "lead-dry-gel batteries" in their gliders. They install AGM batteries with maximum discharge current for 5 seconds of 330 Amps. Try that with your battery. Relying on Chinese mass produced circuits for your safety is not something that I would be willing to do at these current levels. Odyssey PC680 is an AGM battery, which is the same type as the one installed by Schleicher.


The Schleicher spec is "lead-dry-gel batteries, quoted directly from the AS maintenance manual, section 2.8. I don't make this stuff up. That is not an AGM battery. They currently ship LiFePo4 batteries in a new glider. I'd like to know what you are going to do with 330 amps for 5 seconds? Arc weld with it? The starter does not draw anywhere near that, even with the propeller locked. The wires are only #6, and before than 6x#14. The rated carrying capacity of #6 is 102 amps. You will fry the wires. You will fry the switch and the solenoid and connectors. The starter will burn to a crisp. I do not wish to try that with any battery in my glider, it is exactly why I prefer the safety of the LFP with a disconnect, as opposed to a PC680 which can short circuit far more than that. I don't want to start a fire, I just want to start my engine. This isn't a "my battery is bigger than your battery" situation.

The Yuasa and Panasonic AGM batteries most are using are likely made in China, as are at least half of the electronics in your glider. The main tire and tube are made in Brazil or China, I'm a lot more concerned about that than the battery. We risk our lives everyday on Chinese mass produced circuits - where do you think the circuits in your car's ABS and air bag system come from?


John, again not true. Schleicher did not want to install LiFePo4 as a starting battery in my glider. I was told they will not do it for safety reason. The whole point is that you are using your LiFePo4 battery close to its design current output and you are relying on the mass produced Chinese electronics to keep you safe. That might work in a motorcycle but it is not really a good idea in an aircraft. The AGM batteries are also produced in China but they don't rely on a cheap circuit board to function properly.
The circuit in my car does not concern me in this discussion. I am not flying my car. Did you check with FAA in regards to installing LiFePo4 battery in your glider?


Andrzej, you are just talking nonsense. Schleicher does install LiFePo4 batteries in gliders now (after they have been invented). My LiFePo4 is being used no closer to its design current output than the original equipment Yuasa, and then only for 2 seconds while the starter button is pressed. Read the specs. All electronic circuits are mass produced, and most of them in China. Did you check with the FAA before you put the Odyssey battery in your glider? It is a TPT AGM battery, and not similar to the Yuasa which is a traditional thick plate AGM, their characteristics are significantly different. It is not a gel which Schleicher explicitly requires.

Literally thousands of people are using LFP batteries in gliders. I'm not the first. But you need to explain to me why my safety is at risk. *** Exactly what failure mode are you concerned about?***

I'll give you a scenario for yours: the cheap Chinese cable clip used in the engine bay to secure the battery cable falls out, letting the positive battery cable fall against the engine. That short circuits the battery when the starter button is pressed, sinking 1000 amps and setting the entire wiring harness on fire, which passes right under your butt and next to the fuel tank. "Houston, we have a problem...."

I may have only "mass produced Chinese circuits" to prevent this from happening in my glider, but at least I have something.
  #37  
Old March 23rd 18, 05:56 PM posted to rec.aviation.soaring
Jonathan St. Cloud
external usenet poster
 
Posts: 1,463
Default The inadvisability of charging LiFePO4 batteries below 32F/0C(aka below freezing)

On Friday, March 23, 2018 at 8:48:40 AM UTC-7, jfitch wrote:

I'll give you a scenario for yours: the cheap Chinese cable clip used in the engine bay to secure the battery cable falls out, letting the positive battery cable fall against the engine. That short circuits the battery when the starter button is pressed, sinking 1000 amps and setting the entire wiring harness on fire, which passes right under your butt and next to the fuel tank. "Houston, we have a problem...."

I may have only "mass produced Chinese circuits" to prevent this from happening in my glider, but at least I have something.


Not a direct reply, but I took delivery of a brand new glider from Schleicher that had one (out of four) bad LFP battery. All the batteries are fused at the battery with circuit breaker on panel for each instrument. Kept blowing fuses. Schleicher told me they had not heard of a battery going bad, but quickly refunded monies to purchase a new battery. No problems with new battery. I have also had a NiCad runaway on a helicopter (at sunset of course in the mountains). Batteries burn really well. Life is full of risk v reward. Know your risks and reward.
  #38  
Old March 23rd 18, 08:28 PM posted to rec.aviation.soaring
[email protected]
external usenet poster
 
Posts: 465
Default The inadvisability of charging LiFePO4 batteries below 32F/0C(aka below freezing)

Can you explain what was "bad" with this battery, and can such a problem develop eventually in a good battery? I'm puzzled what would cause the fuse at the battery to blow when there wasn't a short circuit downstream.

On Friday, March 23, 2018 at 12:56:41 PM UTC-4, Jonathan St. Cloud wrote:
Not a direct reply, but I took delivery of a brand new glider from Schleicher that had one (out of four) bad LFP battery. All the batteries are fused at the battery with circuit breaker on panel for each instrument. Kept blowing fuses. Schleicher told me they had not heard of a battery going bad, but quickly refunded monies to purchase a new battery. No problems with new battery. I have also had a NiCad runaway on a helicopter (at sunset of course in the mountains). Batteries burn really well. Life is full of risk v reward. Know your risks and reward.


  #39  
Old March 23rd 18, 08:34 PM posted to rec.aviation.soaring
Andrzej Kobus
external usenet poster
 
Posts: 585
Default The inadvisability of charging LiFePO4 batteries below 32F/0C(aka below freezing)

On Friday, March 23, 2018 at 11:48:40 AM UTC-4, jfitch wrote:
On Friday, March 23, 2018 at 3:43:18 AM UTC-7, Andrzej Kobus wrote:
On Friday, March 23, 2018 at 1:03:01 AM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 7:21:37 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 10:04:02 PM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 3:37:31 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 1:09:13 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 5:00:32 PM UTC-7, Andrzej Kobus wrote:
On Wednesday, March 21, 2018 at 7:18:52 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 12:12:31 PM UTC-7, Tango Eight wrote:
On Wednesday, March 21, 2018 at 2:15:26 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 10:22:48 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
While I usually don't disagree with you, if you READ what Tango8 posted, he is saying the same thing as you.
"Lithium in the name does make it the same", as I read it.

Your thoughts?!

Yes, I am going from early (late '70's NiCads to more modern LiFe or LiOn/LiPo) rechargeables including LA of various flavors.

I have a bunch of cash tied up in chargers for various battery chemistries, mostly in RC use, but also for my main income.

Hey, hey find an issue with my read of Tango8's post, I am willing to learn, but I believe you read it wrong.

I don't believe it is dangerous to refer to Lithium Ion batteries as Lithium Ion batteries. But in T8s post he said it was, and further said '"LiIon" vs "LiPo" vs "LFP"' which implies that Lithium Ion batteries are a type of Lithium Ion batteries. The semantics matter. Had he quoted my post in context (the complete sentence was "If it has lithium in it, it is a Lithium Ion battery, but beyond that there are big differences in chemistry and mechanical construction.") perhaps he would have not thought what I said dangerous. You cannot charge a LiIon battery differently than an LFP, because an LFP IS a LiIon battery. LiIon includes all the different chemistries but the members of that group differ in their associated charge requirements.

It is much better to use language precisely when the result of a misunderstanding can be an explosion and fire. If you specify an LFP charger you should get want you want. If you specify a LiIon charger you have no idea what you are going to get.

Jon, you're clearly unfamiliar with the terminology as it is used out in the real world. There are many (millions) multi-mode chargers out there that use the terms as I have used them, "LiIon, LiPo, LFP". Semantics matter? Sure. Safety based on correctly matching charging cycles to chemistry matters more.

Here's a link to the instructions for a commercial charger that illustrates what I am talking about. They use the terms LiIo, and LiFe instead of LiIon and LFP.

http://www.ircha.org/sites/default/f...ntam%20BC6.pdf

I am well aware of the loose and incorrect usage of terms, and it is what I am arguing against as potentially dangerous. As I said in my second post in this thread, "unfortunately there is confusion". What exactly is the voltage and chemistry of a LiIo, or LiIon, or Lithium battery? In the real world, Google "lithium ion battery" will correctly return hits on all types, not just lithium polymer, with recommended charging voltage of between 3.2 and several hundred volts. Even in the last few of posts we have the conflation of several chemistries. The news media is horribly guilty of this, from them we know that lithium batteries cause cars and aircraft to catch fire and burn, and hoverboards to self immolate. I have been told on this very forum that lithium ion batteries should not be used in gliders because they cause Boeing 787s and Chevy Volts and Samsung S7s to burn - never mind that those batteries are quite different than the ones we use.

If I have a charger than says "LiIo" or "lithium" charger on it, that tells me little or nothing about what battery I can charge with it. This is my point. "Correctly matching charing cycles to chemistry" can only be done if the specific chemistry or voltages required are stated. "Lithium ion" is the term used for the collection of chemistries using lithium anodes or cathodes. If that is not the correct term, then what is? And why is it "dangerous" to use the correct term? And if speaking in a context where the specific chemistry dangerously matters, shouldn't the specific term be used, rather than the general?

John, I am sorry, but aren't you the one who uses unapproved, for starting, LiFePo4 batteries in your ASH-26E for engine starting? I am surprised you seem to lecture others while you do questionable things yourself, just saying.

Andrzej, the Schleicher maintenance manual (which specifies SLA batteries for both engine AND avionics) was written in 1995, and is not likely to consider a battery technology invented in 1996. Anyone flying an ASW 27 or 29 should similarly not use an LFP battery for avionics as they are not an approved type. Yet nearly every glider supply outlet sells them for this purpose, and I note that Schleicher ships LFP batteries for both start and avionics in many of their current gliders.

I'm not lecturing (or even recommending) people to use or not use anything. I educated myself on what was required and acted accordingly based on facts, not questions. I AM asking that they use precise language, where precise language is important. Schleicher does not say "use a lead battery", rather they say "use a maintenance free lead-dry-gel battery" - because installing a flooded lead acid battery on its side near your butt is a bad idea. Even then they are imprecise - the battery they call out is an AGM, not a gel and these have different charge requirements. The terminology matters.

John, the battery you are using was not designed for starting purposes. The CTC LFP128198 is only rated for 100 Amps for 30 sec, not as you stated in another thread at 160 Amps for 30 sec. 160 Amp is the rating of the protection circuit with is not enough in this application (http://sepbatteries.com/media/add_info/LFP128198.pdf). You are simply operating this battery at very thin safety margins. I am surprised that this does not bother you. A more appropriate solution would be EarthX battery specifically build for experimental aircraft as an engine starting battery, http://earthxbatteries.com/product-c...ental-aircraft
Yes, it is very expensive but your life is priceless, or a better solution; or better yet the Odyssey PC680 Battery

Andrzej, I appreciate your concern for me. I did misstate the spec, it is 100 amps for 30 seconds. (In a conversation with the designer, he said 150 amps for several seconds). Fortunately that is more than adequate to start the engine (I have measured the starting current, typically 80 amps for 3 seconds, and it has been routinely starting my engine for 3 years now). CTC in their marketing literature has stated that the battery is designed for engine start use. But perhaps the biggest problem I have is the characterization that this is a safety issue. It is not a safety issue. In the worst case, the battery will go into overcurrent protection and disconnect.. If you are flying a motorglider in any situation where a dead starting battery is a safety issue, you need to review your flying practices. Even the ASH flight manual warns against this in section 4.5.1, "One must always be prepared for the possibility that the power plant will fail to deliver the hoped for propulsion." I love that sentence.

Second, you apparently have not looked into the specifications of the SLA battery Schleicher specifies. It is the Yuasa 18-12, the data sheet spec's a maximum discharge of 112 amps. Are they "simply operating this battery at very thin safety margins"? It is much more likely to reach that maximum than the CTC, because the internal resistance is much higher and the starter voltage lower. It is not advertised or spec'd for engine start use.. The Odyssey PC680 is a TPT starved electrolyte battery and does not meet Schleicher's specification of a "lead-dry-gel battery". These batteries ARE a safety issue as they have no internal overcurrent protection and will literally melt down in a fault. There is no fault protection in the starting circuit of an ASH26.

The earthX battery does not fit in the hole. There are other LFP motorcycle "starter" batteries that will, but most do not have the same true AH capacity.

You may use whatever battery you like, but don't worry about me - I'm perfectly safe.

John, sorry to disappoint you, Schleicher does not install "lead-dry-gel batteries" in their gliders. They install AGM batteries with maximum discharge current for 5 seconds of 330 Amps. Try that with your battery. Relying on Chinese mass produced circuits for your safety is not something that I would be willing to do at these current levels. Odyssey PC680 is an AGM battery, which is the same type as the one installed by Schleicher.

The Schleicher spec is "lead-dry-gel batteries, quoted directly from the AS maintenance manual, section 2.8. I don't make this stuff up. That is not an AGM battery. They currently ship LiFePo4 batteries in a new glider. I'd like to know what you are going to do with 330 amps for 5 seconds? Arc weld with it? The starter does not draw anywhere near that, even with the propeller locked. The wires are only #6, and before than 6x#14. The rated carrying capacity of #6 is 102 amps. You will fry the wires. You will fry the switch and the solenoid and connectors. The starter will burn to a crisp. I do not wish to try that with any battery in my glider, it is exactly why I prefer the safety of the LFP with a disconnect, as opposed to a PC680 which can short circuit far more than that. I don't want to start a fire, I just want to start my engine. This isn't a "my battery is bigger than your battery" situation.

The Yuasa and Panasonic AGM batteries most are using are likely made in China, as are at least half of the electronics in your glider. The main tire and tube are made in Brazil or China, I'm a lot more concerned about that than the battery. We risk our lives everyday on Chinese mass produced circuits - where do you think the circuits in your car's ABS and air bag system come from?


John, again not true. Schleicher did not want to install LiFePo4 as a starting battery in my glider. I was told they will not do it for safety reason. The whole point is that you are using your LiFePo4 battery close to its design current output and you are relying on the mass produced Chinese electronics to keep you safe. That might work in a motorcycle but it is not really a good idea in an aircraft. The AGM batteries are also produced in China but they don't rely on a cheap circuit board to function properly.
The circuit in my car does not concern me in this discussion. I am not flying my car. Did you check with FAA in regards to installing LiFePo4 battery in your glider?


Andrzej, you are just talking nonsense. Schleicher does install LiFePo4 batteries in gliders now (after they have been invented). My LiFePo4 is being used no closer to its design current output than the original equipment Yuasa, and then only for 2 seconds while the starter button is pressed. Read the specs. All electronic circuits are mass produced, and most of them in China. Did you check with the FAA before you put the Odyssey battery in your glider? It is a TPT AGM battery, and not similar to the Yuasa which is a traditional thick plate AGM, their characteristics are significantly different. It is not a gel which Schleicher explicitly requires.

Literally thousands of people are using LFP batteries in gliders. I'm not the first. But you need to explain to me why my safety is at risk. *** Exactly what failure mode are you concerned about?***

I'll give you a scenario for yours: the cheap Chinese cable clip used in the engine bay to secure the battery cable falls out, letting the positive battery cable fall against the engine. That short circuits the battery when the starter button is pressed, sinking 1000 amps and setting the entire wiring harness on fire, which passes right under your butt and next to the fuel tank. "Houston, we have a problem...."

I may have only "mass produced Chinese circuits" to prevent this from happening in my glider, but at least I have something.


Wow, don't twist my words. I said they don't install them as starter batteries, that does not mean that they don't install them in low current applications.

I did not have to check with FAA because my battery is lead acid battery of AGM type the same type Schleicher installed in my glider. Thousands of people use LiFePo4 batteries in their gliders but not as starter batteries.

If that cheap circuit of yours gets overloaded and starts fire it will be right under your body parts and releasing the starter button will not extinguish that fire in anyway.

The problem with much of your write is that it is not credible and here it is why:
In 2016 you wrote
"Not a DG, but I have been using an LiFeP04 for the engine start battery in my ASH26E for a year now. While the engine start battery can power the avionics, I have a separate (LiFePo4) battery for that. You need to find a Li battery that fits in the same spot, has charge/discharge/current protections built in, and has a max discharge capacity sufficient to crank the starter reliably. I measured the ASH starter at 150 amps stall current and 100 or so while cranking. The battery I am using is a CTC LFP128198, rated at 19.8 AH and 160 amps discharge for 30 seconds. "

This year you wrote:
"Fortunately that is more than adequate to start the engine (I have measured the starting current, typically 80 amps for 3 seconds, and it has been routinely starting my engine for 3 years now)."

Maybe you should make up your mind what the real numbers are for what the starter can take in terms of current and what the battery can deliver, because you were wrong on that too.

You were also wrong on the battery type that Schleicher puts in our gliders.. I got my 31 very recently delivered in 2016 and I asked Schleicher about LiFePo4 battery for a starter. They refused to do it on the grounds of safety.

John, treat yourself to the last word on this subject because that what you need to feel better. You wore me out...
  #40  
Old March 24th 18, 12:35 AM posted to rec.aviation.soaring
Jonathan St. Cloud
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Posts: 1,463
Default The inadvisability of charging LiFePO4 batteries below 32F/0C(aka below freezing)

I have no idea why is was "bad". I just knew that every time I took glider out of box fuse was melted. We checked the trailer top solar chargers with controllers, they were fine as was solar charger and controller in glider.. One bad one out of bunch, replaced it no further problems.


On Friday, March 23, 2018 at 12:28:46 PM UTC-7, wrote:
Can you explain what was "bad" with this battery, and can such a problem develop eventually in a good battery? I'm puzzled what would cause the fuse at the battery to blow when there wasn't a short circuit downstream.

On Friday, March 23, 2018 at 12:56:41 PM UTC-4, Jonathan St. Cloud wrote:
Not a direct reply, but I took delivery of a brand new glider from Schleicher that had one (out of four) bad LFP battery. All the batteries are fused at the battery with circuit breaker on panel for each instrument. Kept blowing fuses. Schleicher told me they had not heard of a battery going bad, but quickly refunded monies to purchase a new battery. No problems with new battery. I have also had a NiCad runaway on a helicopter (at sunset of course in the mountains). Batteries burn really well. Life is full of risk v reward. Know your risks and reward.


 




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