LiFePO4 chargers

[[email protected]]

My CP1230 LiFePO4 battery charger went south. Any suggestions on a replacement? What are you using for LiFePO4 batteries? Mine are 15 AH with BMS.

[AS]

On Sunday, November 4, 2018 at 12:52:40 PM UTC-5, wrote:
> My CP1230 LiFePO4 battery charger went south. Any suggestions on a replacement? What are you using for LiFePO4 batteries? Mine are 15 AH with BMS.

2ea. K2B12V10EB (12.8V 9.6Ah, 122.9Whr) in parallel plus their charger K2C12V4A.
Have used them for years and they have not gone flat even during long flights while running the transponder.
Uli
'AS'

[JS[_5_]]

On Sunday, November 4, 2018 at 9:52:40 AM UTC-8, wrote:
> My CP1230 LiFePO4 battery charger went south. Any suggestions on a replacement? What are you using for LiFePO4 batteries? Mine are 15 AH with BMS.

I've used a few LiFePO4 batteries and chargers.
The ASG29 has 3x 10AH Tenergy LiFePO4 (2 in parallel, one separate) and one 3AH Bioenno in the tail as battery 2 of the Air-Glide. Powers CN2 display, CN Vario, Air-Glide S, PowerFlarm, Trig TT22 and Trig TY91 all day.
The Duo has 2x Bioenno LiFePO4 (9AH?) batteries, with comparitive performance similar to the price comparison.
For chargers, liking the Tenergy TB6AC, which will charge different chemistries and cell counts.
Bioenno also sell LiFePO4 solar charge controllers for the trailer or glider.
https://www.bioennopower.com/collections/solar-charger-controllers
Jim

http://www.all-battery.com/Tenergytb6acplus80wbalancecharger-01436.aspx

[[email protected]]

On Sunday, November 4, 2018 at 9:52:40 AM UTC-8, wrote:
> My CP1230 LiFePO4 battery charger went south. Any suggestions on a replacement? What are you using for LiFePO4 batteries? Mine are 15 AH with BMS.

Not quite on topic, but I charge my LiFePo4 battery at home during the week. Since I've read about fires from such batteries, I put the battery inside an old steel toolbox, on my garage floor, with nothing near it.

[[email protected]]

I also have heard the stories about fires while charging, but, as far as I know, most involved a different Lithium chemistry (Li-ion, Li-Polymer etc.) LiFePO4 is supposed to be safer, but by how much I do not know. At any rate, I am pretty much stuck with charging them in the plane, as they are mounted well behind the spar, and it takes a good 20-30 minutes to get them out and put them back in.

[[email protected]]

On Monday, November 5, 2018 at 8:02:04 AM UTC+10, wrote:
> I also have heard the stories about fires while charging, but, as far as I know, most involved a different Lithium chemistry (Li-ion, Li-Polymer etc..) LiFePO4 is supposed to be safer, but by how much I do not know. At any rate, I am pretty much stuck with charging them in the plane, as they are mounted well behind the spar, and it takes a good 20-30 minutes to get them out and put them back in.

Here is an FAA report that supports the assertion that LiFePO4 cells are safer: https://www.fire.tc.faa.gov/pdf/TC-16-17.pdf

In their testing, which they admit had quite variable results, they did not get any thermal runaway with LiFePO4 cells, but did with all the other Li chemistries they tested. Note that the graphs in the above article show 1 cell out of 5 consumed by "thermal runaway" but that was the cell that they were heating externally to try and initiate the runaway.

Not to say that you shouldn't take precautions, all battery chemistries store enough energy to start an electrical fire, even if they are relatively immune to thermal runaway and overcharging.

[[email protected]]

Thanks for the link to the FAA test. I picked up one conclusion that made reading the whole thing worthwhile, even though I am not an Electrical Engineer and do not claim to understand the report completely:

"In general, of all of the lithium-ion cells that were tested, LiFePO4 would be considered the safest cathode material because of the relatively low temperature rise and the resulting low likelihood for thermal runaway to propagate. LiCoO2 and LiMnNi would be considered the most hazardous because of the relatively large temperature rise and high probability for propagation of thermal runaway to adjacent battery cells."

Once again, thanks for the link.

[[email protected]]

You should take a look at the CTEK Lithium US charger.
Fully automatic.
Performs battery testing.
Can leave on float.

[George Haeh]

+1 on the CTEK LiFePO4 charger. Not cheap, but it has several charging stages that really do stuff the battery full of charge - and much cheaper than buying new LiFePO4s.

The first few times I charged up my K2s (previously charged with a Fuyuang 14.6 Li-ion) it took some hours to step through the charging stages. The manual explains the charging stages.

I ran one battery over three extended flights and the voltage stayed up. The Air Glide S shows the voltage dropping 0.1 or 0.2 V; then coming back up a number of times. The BMS is on top of the job.

[[email protected]]

Thanks for the report. As I recall the FAA is also tracking battery fire incidents of various Lithium Ion types and I don't ever recall mention of LifePo4 variant at least in commercially reported cases.

For chargers, RC community would probably agree Hyperion are excellent.. whether the battery has or doesn't have BMS. And I also like Hitec for the ability to use a thermal sensor during charge for emergency shutoff.

[kinsell]

On 11/4/18 3:51 PM, wrote:
> On Monday, November 5, 2018 at 8:02:04 AM UTC+10, wrote:
>> I also have heard the stories about fires while charging, but, as far as I know, most involved a different Lithium chemistry (Li-ion, Li-Polymer etc.) LiFePO4 is supposed to be safer, but by how much I do not know. At any rate, I am pretty much stuck with charging them in the plane, as they are mounted well behind the spar, and it takes a good 20-30 minutes to get them out and put them back in.
>
> Here is an FAA report that supports the assertion that LiFePO4 cells are safer: https://www.fire.tc.faa.gov/pdf/TC-16-17.pdf
>
> In their testing, which they admit had quite variable results, they did not get any thermal runaway with LiFePO4 cells, but did with all the other Li chemistries they tested. Note that the graphs in the above article show 1 cell out of 5 consumed by "thermal runaway" but that was the cell that they were heating externally to try and initiate the runaway.
>
> Not to say that you shouldn't take precautions, all battery chemistries store enough energy to start an electrical fire, even if they are relatively immune to thermal runaway and overcharging.
>

I would hope they're safer than something like a li-po, model airplanes
using those things routinely put on a fireworks display during a crash.
Fascinating videos on YouTube.

However, "safer" isn't actually the same as "safe", LFP's are quite
capable of burning, despite what the scholarly articles say. There have
been a number of fires, particularly when they're used as starter
batteries. High charge rates and very high discharge rates seem to
cause problems, as homebuilders of small power planes have discovered.
There was also that LFP battery fire in an EB-28 in Finland this summer.

-Dave

[[email protected]]

On Saturday, November 10, 2018 at 12:03:42 AM UTC-6, kinsell wrote:
> On 11/4/18 3:51 PM, wrote:
> > On Monday, November 5, 2018 at 8:02:04 AM UTC+10, wrote:
> >> I also have heard the stories about fires while charging, but, as far as I know, most involved a different Lithium chemistry (Li-ion, Li-Polymer etc.) LiFePO4 is supposed to be safer, but by how much I do not know. At any rate, I am pretty much stuck with charging them in the plane, as they are mounted well behind the spar, and it takes a good 20-30 minutes to get them out and put them back in.
> >
> > Here is an FAA report that supports the assertion that LiFePO4 cells are safer: https://www.fire.tc.faa.gov/pdf/TC-16-17.pdf
> >
> > In their testing, which they admit had quite variable results, they did not get any thermal runaway with LiFePO4 cells, but did with all the other Li chemistries they tested. Note that the graphs in the above article show 1 cell out of 5 consumed by "thermal runaway" but that was the cell that they were heating externally to try and initiate the runaway.
> >
> > Not to say that you shouldn't take precautions, all battery chemistries store enough energy to start an electrical fire, even if they are relatively immune to thermal runaway and overcharging.
> >
>
> I would hope they're safer than something like a li-po, model airplanes
> using those things routinely put on a fireworks display during a crash.
> Fascinating videos on YouTube.
>
> However, "safer" isn't actually the same as "safe", LFP's are quite
> capable of burning, despite what the scholarly articles say. There have
> been a number of fires, particularly when they're used as starter
> batteries. High charge rates and very high discharge rates seem to
> cause problems, as homebuilders of small power planes have discovered.
> There was also that LFP battery fire in an EB-28 in Finland this summer.
>
> -Dave

Dave, if you look around youtube long enough, you will find that a AAA battery can make a fire. Certainly a 12V lead-acid has enough juice to do that if circumstances are right. The overwhelming evidence of many years of usage of LiFePo4 chemistry in glider batteries suggests that they are as safe as the old gel-cells. Give progress a chance, I'm not saying be a Progressive.
Herb

[[email protected]]

Mark, When K2 was fairly new on the market I contacted them asking if Battery Tender Jr. is okay and safe, they replied that it is perfectly okay and nearly the same as their charger. I also contacted Battery Tender Jr. with the reverse question and they said the BTJr is fine for LiFePO4. I used the BTJr for years on my K2 with no issues. They're about $25 on internet sites.

[kinsell]

On 11/13/18 6:08 PM, wrote:
> Mark, When K2 was fairly new on the market I contacted them asking if Battery Tender Jr. is okay and safe, they replied that it is perfectly okay and nearly the same as their charger. I also contacted Battery Tender Jr. with the reverse question and they said the BTJr is fine for LiFePO4. I used the BTJr for years on my K2 with no issues. They're about $25 on internet sites.
>

Have you measured the amount of charge you're getting into the K2's? It
will be considerably less than the rated amount due to using a lead-acid
charger.

Also, if K2 has cell balancing capability, it won't be used because your
Battery Tender doesn't put out enough voltage to make it work.

[kinsell]

On 11/11/18 7:02 AM, wrote:
> On Saturday, November 10, 2018 at 12:03:42 AM UTC-6, kinsell wrote:
>> On 11/4/18 3:51 PM, wrote:
>>> On Monday, November 5, 2018 at 8:02:04 AM UTC+10, wrote:
>>>> I also have heard the stories about fires while charging, but, as far as I know, most involved a different Lithium chemistry (Li-ion, Li-Polymer etc.) LiFePO4 is supposed to be safer, but by how much I do not know. At any rate, I am pretty much stuck with charging them in the plane, as they are mounted well behind the spar, and it takes a good 20-30 minutes to get them out and put them back in.
>>>
>>> Here is an FAA report that supports the assertion that LiFePO4 cells are safer: https://www.fire.tc.faa.gov/pdf/TC-16-17.pdf
>>>
>>> In their testing, which they admit had quite variable results, they did not get any thermal runaway with LiFePO4 cells, but did with all the other Li chemistries they tested. Note that the graphs in the above article show 1 cell out of 5 consumed by "thermal runaway" but that was the cell that they were heating externally to try and initiate the runaway.
>>>
>>> Not to say that you shouldn't take precautions, all battery chemistries store enough energy to start an electrical fire, even if they are relatively immune to thermal runaway and overcharging.
>>>
>>
>> I would hope they're safer than something like a li-po, model airplanes
>> using those things routinely put on a fireworks display during a crash.
>> Fascinating videos on YouTube.
>>
>> However, "safer" isn't actually the same as "safe", LFP's are quite
>> capable of burning, despite what the scholarly articles say. There have
>> been a number of fires, particularly when they're used as starter
>> batteries. High charge rates and very high discharge rates seem to
>> cause problems, as homebuilders of small power planes have discovered.
>> There was also that LFP battery fire in an EB-28 in Finland this summer.
>>
>> -Dave
>
> Dave, if you look around youtube long enough, you will find that a AAA battery can make a fire. Certainly a 12V lead-acid has enough juice to do that if circumstances are right. The overwhelming evidence of many years of usage of LiFePo4 chemistry in glider batteries suggests that they are as safe as the old gel-cells. Give progress a chance, I'm not saying be a Progressive.
> Herb
>
If you come across a YouTube video of an AAA battery filling a cockpit
with toxic smoke, you be sure to post the link, OK?

Meanwhile, this is the sort of progress I can live without:

https://www.pilotsofamerica.com/community/threads/aircraft-lithium-battery-fires.102016/

-Dave

[Jim White[_3_]]

Not all LifePo4 battery chemistry is the same. When I fitted 2 LifePO4
batteries to my 27 I chose A123 because of their chemistry and BMC. See
here: https://tinyurl.com/ybmof8qh

Unfortunately theses batteries were only 4.5AH but because of the way the
voltage stays good until the BMC shuts the battery down I have never run
out of power.

Also unfortunately, I am not sure that the 12V7 form factor is still
available so I am hoping that the rated 5000 cycles will see me out!

Jim

[Dan Marotta]

The original poster called the battery a "Lithium Iron".Â* Later on in
the thread someone said, "Lithium Ion".Â* Which is it?Â* I haven't yet
heard of a Lithium Iron Phosphate (LiFePO4) battery causing a problem.Â*
Stemme installs LiFePO4 batteries in the S-12 new from the factory.

On 11/13/2018 9:18 PM, kinsell wrote:
> On 11/11/18 7:02 AM, wrote:
>> On Saturday, November 10, 2018 at 12:03:42 AM UTC-6, kinsell wrote:
>>> On 11/4/18 3:51 PM, wrote:
>>>> On Monday, November 5, 2018 at 8:02:04 AM UTC+10,
>>>> wrote:
>>>>> I also have heard the stories about fires while charging, but, as
>>>>> far as I know, most involved a different Lithium chemistry
>>>>> (Li-ion, Li-Polymer etc.) LiFePO4 is supposed to be safer, but by
>>>>> how much I do not know. At any rate, I am pretty much stuck with
>>>>> charging them in the plane, as they are mounted well behind the
>>>>> spar, and it takes a good 20-30 minutes to get them out and put
>>>>> them back in.
>>>>
>>>> Here is an FAA report that supports the assertion that LiFePO4
>>>> cells are safer: https://www.fire.tc.faa.gov/pdf/TC-16-17.pdf
>>>>
>>>> In their testing, which they admit had quite variable results, they
>>>> did not get any thermal runaway with LiFePO4 cells, but did with
>>>> all the other Li chemistries they tested. Note that the graphs in
>>>> the above article show 1 cell out of 5 consumed by "thermal
>>>> runaway" but that was the cell that they were heating externally to
>>>> try and initiate the runaway.
>>>>
>>>> Not to say that you shouldn't take precautions, all battery
>>>> chemistries store enough energy to start an electrical fire, even
>>>> if they are relatively immune to thermal runaway and overcharging.
>>>>
>>>
>>> I would hope they're safer than something like a li-po, model airplanes
>>> using those things routinely put on a fireworks display during a crash.
>>> Fascinating videos on YouTube.
>>>
>>> However, "safer" isn't actually the same as "safe", LFP's are quite
>>> capable of burning, despite what the scholarly articles say. There have
>>> been a number of fires, particularly when they're used as starter
>>> batteries.Â* High charge rates and very high discharge rates seem to
>>> cause problems, as homebuilders of small power planes have discovered.
>>> There was also that LFP battery fire in an EB-28 in Finland this
>>> summer.
>>>
>>> -Dave
>>
>> Dave, if you look around youtube long enough, you will find that a
>> AAA battery can make a fire. Certainly a 12V lead-acid has enough
>> juice to do that if circumstances are right. The overwhelming
>> evidence of many years of usage of LiFePo4 chemistry in glider
>> batteries suggests that they are as safe as the old gel-cells. Give
>> progress a chance, I'm not saying be a Progressive.
>> Herb
>>
> If you come across a YouTube video of an AAA battery filling a cockpit
> with toxic smoke, you be sure to post the link, OK?
>
> Meanwhile, this is the sort of progress I can live without:
>
> https://www.pilotsofamerica.com/community/threads/aircraft-lithium-battery-fires.102016/
>
>
> -Dave
>

--
Dan, 5J

[[email protected]]

On Tuesday, November 13, 2018 at 11:11:52 PM UTC-5, kinsell wrote:
> On 11/13/18 6:08 PM, bruce... wrote:
> > Mark, When K2 was fairly new on the market I contacted them asking if Battery Tender Jr. is okay and safe, they replied that it is perfectly okay and nearly the same as their charger. I also contacted Battery Tender Jr. with the reverse question and they said the BTJr is fine for LiFePO4. I used the BTJr for years on my K2 with no issues. They're about $25 on internet sites.
> >
>
> Have you measured the amount of charge you're getting into the K2's? It
> will be considerably less than the rated amount due to using a lead-acid
> charger.
>
> Also, if K2 has cell balancing capability, it won't be used because your
> Battery Tender doesn't put out enough voltage to make it work.

Many simple lead-acid chargers reach up to around 14.2-14.8 volts. That voltage would suffice to charge an LFP battery to well above 90% capacity if it stays there for a while. If it quickly shifts to "float" at 13.5V or so then it won't do well in charging LFP. So simpler is better in this case. Measure what your charger does. And disconnect it after several hours, don't leave it on "float".

[[email protected]]

On Tuesday, November 13, 2018 at 10:19:34 PM UTC-6, kinsell wrote:
> On 11/11/18 7:02 AM, wrote:
> > On Saturday, November 10, 2018 at 12:03:42 AM UTC-6, kinsell wrote:
> >> On 11/4/18 3:51 PM, wrote:
> >>> On Monday, November 5, 2018 at 8:02:04 AM UTC+10, wrote:
> >>>> I also have heard the stories about fires while charging, but, as far as I know, most involved a different Lithium chemistry (Li-ion, Li-Polymer etc.) LiFePO4 is supposed to be safer, but by how much I do not know. At any rate, I am pretty much stuck with charging them in the plane, as they are mounted well behind the spar, and it takes a good 20-30 minutes to get them out and put them back in.
> >>>
> >>> Here is an FAA report that supports the assertion that LiFePO4 cells are safer: https://www.fire.tc.faa.gov/pdf/TC-16-17.pdf
> >>>
> >>> In their testing, which they admit had quite variable results, they did not get any thermal runaway with LiFePO4 cells, but did with all the other Li chemistries they tested. Note that the graphs in the above article show 1 cell out of 5 consumed by "thermal runaway" but that was the cell that they were heating externally to try and initiate the runaway.
> >>>
> >>> Not to say that you shouldn't take precautions, all battery chemistries store enough energy to start an electrical fire, even if they are relatively immune to thermal runaway and overcharging.
> >>>
> >>
> >> I would hope they're safer than something like a li-po, model airplanes
> >> using those things routinely put on a fireworks display during a crash..
> >> Fascinating videos on YouTube.
> >>
> >> However, "safer" isn't actually the same as "safe", LFP's are quite
> >> capable of burning, despite what the scholarly articles say. There have
> >> been a number of fires, particularly when they're used as starter
> >> batteries. High charge rates and very high discharge rates seem to
> >> cause problems, as homebuilders of small power planes have discovered.
> >> There was also that LFP battery fire in an EB-28 in Finland this summer.

[kinsell]

On 11/14/18 9:03 AM, wrote:
> On Tuesday, November 13, 2018 at 11:11:52 PM UTC-5, kinsell wrote:
>> On 11/13/18 6:08 PM, bruce... wrote:
>>> Mark, When K2 was fairly new on the market I contacted them asking if Battery Tender Jr. is okay and safe, they replied that it is perfectly okay and nearly the same as their charger. I also contacted Battery Tender Jr. with the reverse question and they said the BTJr is fine for LiFePO4. I used the BTJr for years on my K2 with no issues. They're about $25 on internet sites.
>>>
>>
>> Have you measured the amount of charge you're getting into the K2's? It
>> will be considerably less than the rated amount due to using a lead-acid
>> charger.
>>
>> Also, if K2 has cell balancing capability, it won't be used because your
>> Battery Tender doesn't put out enough voltage to make it work.
>
> Many simple lead-acid chargers reach up to around 14.2-14.8 volts. That voltage would suffice to charge an LFP battery to well above 90% capacity if it stays there for a while. If it quickly shifts to "float" at 13.5V or so then it won't do well in charging LFP. So simpler is better in this case. Measure what your charger does. And disconnect it after several hours, don't leave it on "float".
>

Hate to break this to you, but at $24, the Battery Tender Junior is one
of the cheapest chargers on the market, and is fully featured with a
float mode.

14.2 volts wouldn't begin to charge an LFP to "well over 90%" as you
claim. If you found a charger that delivers 14.8 volts under load, then
it would overcharge an SLA and would be considered defective.

If you're going to spend big bucks for an LFP, you ought to get a proper
charger for it. Still waiting to hear just how much charge the K2's got
in them from a BTJ.

-Dave

[[email protected]]

On Wednesday, November 14, 2018 at 2:56:35 PM UTC-5, kinsell wrote:
> On 11/14/18 9:03 AM, moshe... wrote:
> > On Tuesday, November 13, 2018 at 11:11:52 PM UTC-5, kinsell wrote:
> >> On 11/13/18 6:08 PM, bruce... wrote:
> >>> Mark, When K2 was fairly new on the market I contacted them asking if Battery Tender Jr. is okay and safe, they replied that it is perfectly okay and nearly the same as their charger. I also contacted Battery Tender Jr. with the reverse question and they said the BTJr is fine for LiFePO4. I used the BTJr for years on my K2 with no issues. They're about $25 on internet sites.
> >>>
> >>
> >> Have you measured the amount of charge you're getting into the K2's? It
> >> will be considerably less than the rated amount due to using a lead-acid
> >> charger.
> >>
> >> Also, if K2 has cell balancing capability, it won't be used because your
> >> Battery Tender doesn't put out enough voltage to make it work.
> >
> > Many simple lead-acid chargers reach up to around 14.2-14.8 volts. That voltage would suffice to charge an LFP battery to well above 90% capacity if it stays there for a while. If it quickly shifts to "float" at 13.5V or so then it won't do well in charging LFP. So simpler is better in this case. Measure what your charger does. And disconnect it after several hours, don't leave it on "float".
> >
>
> Hate to break this to you, but at $24, the Battery Tender Junior is one
> of the cheapest chargers on the market, and is fully featured with a
> float mode.
>
> 14.2 volts wouldn't begin to charge an LFP to "well over 90%" as you
> claim. If you found a charger that delivers 14.8 volts under load, then
> it would overcharge an SLA and would be considered defective.
>
> If you're going to spend big bucks for an LFP, you ought to get a proper
> charger for it. Still waiting to hear just how much charge the K2's got
> in them from a BTJ.
>
> -Dave

That's the conventional wisdom, but see experimental results here:
https://www.powerstream.com/lithium-phosphate-charge-voltage.htm
- well above 90% capacity even at a bit lower than 14V!

A cheap dumb 14.x volt fixed-voltage source with limited current output (and perhaps aided by the battery's BMS) would charge an LFP just fine. I'm not saying that's the ideal charger, but in a pinch it would work well enough. I am not happy with the several chargers I have that push SLAs well above 14V (even above 15V), but they may be handy for LFPs.

[Graham Drinkell[_2_]]

At 20:09 14 November 2018, wrote:
>On Wednesday, November 14, 2018 at 2:56:35 PM UTC-5, kinsell
wrote:
>> On 11/14/18 9:03 AM, moshe... wrote:
>> > On Tuesday, November 13, 2018 at 11:11:52 PM UTC-5,
kinsell wrote:
>> >> On 11/13/18 6:08 PM, bruce... wrote:
>> >>> Mark, When K2 was fairly new on the market I contacted
them asking
>if=
> Battery Tender Jr. is okay and safe, they replied that it is perfectly
>oka=
>y and nearly the same as their charger. I also contacted Battery
Tender
>Jr.=
> with the reverse question and they said the BTJr is fine for
LiFePO4. I
>us=
>ed the BTJr for years on my K2 with no issues. They're about $25
on
>intern=
>et sites.
>> >>>
>> >>
>> >> Have you measured the amount of charge you're getting into
the K2's?
>=
>It
>> >> will be considerably less than the rated amount due to using
>lead-ac=
>id
>> >> charger.
>> >>
>> >> Also, if K2 has cell balancing capability, it won't be used
because
>yo=
>ur
>> >> Battery Tender doesn't put out enough voltage to make it
work.
>> >=20
>> > Many simple lead-acid chargers reach up to around 14.2-14.8
volts.
>Tha=
>t voltage would suffice to charge an LFP battery to well above 90%
>capacity=
> if it stays there for a while. If it quickly shifts to "float" at 13.5V
>o=
>r so then it won't do well in charging LFP. So simpler is better in
this
>c=
>ase. Measure what your charger does. And disconnect it after
several
>hour=
>s, don't leave it on "float".
>> >=20
>>=20
>> Hate to break this to you, but at $24, the Battery Tender Junior
is one=
>=20
>> of the cheapest chargers on the market, and is fully featured
with a=20
>> float mode.
>>=20
>> 14.2 volts wouldn't begin to charge an LFP to "well over 90%" as
you=20
>> claim. If you found a charger that delivers 14.8 volts under
load, then=
>=20
>> it would overcharge an SLA and would be considered defective.
>>=20
>> If you're going to spend big bucks for an LFP, you ought to get a
proper=
>=20
>> charger for it. Still waiting to hear just how much charge the
K2's got=
>=20
>> in them from a BTJ.
>>=20
>> -Dave
>
>That's the conventional wisdom, but see experimental results here:
>https://www.powerstream.com/lithium-phosphate-charge-
voltage.htm
>- well above 90% capacity even at a bit lower than 14V!
>
>A cheap dumb 14.x volt fixed-voltage source with limited current
output
>(an=
>d perhaps aided by the battery's BMS) would charge an LFP just
fine. I'm
>n=
>ot saying that's the ideal charger, but in a pinch it would work well
>enoug=
>h. I am not happy with the several chargers I have that push SLAs
well
>abo=
>ve 14V (even above 15V), but they may be handy for LFPs.
>Personally, I would fly a model aircraft with a lipo battery. Full
size, definitely not! They deform at high altitudes, with the
possibility of fracturing cells? The best bet is to use military spec
batteries that work in space?

[Graham Drinkell[_2_]]

At 00:42 15 November 2018, Graham Drinkell wrote:
>At 20:09 14 November 2018, wrote:
>>On Wednesday, November 14, 2018 at 2:56:35 PM UTC-5, kinsell
>wrote:
>>> On 11/14/18 9:03 AM, moshe... wrote:
>>> > On Tuesday, November 13, 2018 at 11:11:52 PM UTC-5,
>kinsell wrote:
>>> >> On 11/13/18 6:08 PM, bruce... wrote:
>>> >>> Mark, When K2 was fairly new on the market I contacted
>them asking
>>if=
>> Battery Tender Jr. is okay and safe, they replied that it is
perfectly
>>oka=
>>y and nearly the same as their charger. I also contacted Battery
>Tender
>>Jr.=
>> with the reverse question and they said the BTJr is fine for
>LiFePO4. I
>>us=
>>ed the BTJr for years on my K2 with no issues. They're about
$25
>on
>>intern=
>>et sites.
>>> >>>
>>> >>
>>> >> Have you measured the amount of charge you're getting
into
>the K2's?
>>=
>>It
>>> >> will be considerably less than the rated amount due to
using
>>lead-ac=
>>id
>>> >> charger.
>>> >>
>>> >> Also, if K2 has cell balancing capability, it won't be used
>because
>>yo=
>>ur
>>> >> Battery Tender doesn't put out enough voltage to make it
>work.
>>> >=20
>>> > Many simple lead-acid chargers reach up to around 14.2-
14.8
>volts.
>>Tha=
>>t voltage would suffice to charge an LFP battery to well above
90%
>>capacity=
>> if it stays there for a while. If it quickly shifts to "float" at
13.5V
>>o=
>>r so then it won't do well in charging LFP. So simpler is better in
>this
>>c=
>>ase. Measure what your charger does. And disconnect it after
>several
>>hour=
>>s, don't leave it on "float".
>>> >=20
>>>=20
>>> Hate to break this to you, but at $24, the Battery Tender Junior
>is one=
>>=20
>>> of the cheapest chargers on the market, and is fully featured
>with a=20
>>> float mode.
>>>=20
>>> 14.2 volts wouldn't begin to charge an LFP to "well over 90%"
as
>you=20
>>> claim. If you found a charger that delivers 14.8 volts under
>load, then=
>>=20
>>> it would overcharge an SLA and would be considered defective.
>>>=20
>>> If you're going to spend big bucks for an LFP, you ought to get
a
>proper=
>>=20
>>> charger for it. Still waiting to hear just how much charge the
>K2's got=
>>=20
>>> in them from a BTJ.
>>>=20
>>> -Dave
>>
>>That's the conventional wisdom, but see experimental results
here:
>>https://www.powerstream.com/lithium-phosphate-charge-
>voltage.htm
>>- well above 90% capacity even at a bit lower than 14V!
>>
>>A cheap dumb 14.x volt fixed-voltage source with limited current
>output
>>(an=
>>d perhaps aided by the battery's BMS) would charge an LFP just
>fine. I'm
>>n=
>>ot saying that's the ideal charger, but in a pinch it would work
well
>>enoug=
>>h. I am not happy with the several chargers I have that push
SLAs
>well
>>abo=
>>ve 14V (even above 15V), but they may be handy for LFPs.
>>Personally, I would fly a model aircraft with a lipo battery. Full
>size, definitely not! They deform at high altitudes, with the
>possibility of fracturing cells? The best bet is to use military spec
>batteries that work in space?
>
>
>

[Eric Greenwell[_4_]]

kinsell wrote on 11/14/2018 12:55 PM:
> On 11/14/18 9:03 AM, wrote:
>> On Tuesday, November 13, 2018 at 11:11:52 PM UTC-5, kinsell wrote:
>>> On 11/13/18 6:08 PM, bruce... wrote:
>>>> Mark, When K2 was fairly new on the market I contacted them asking if Battery
>>>> Tender Jr. is okay and safe, they replied that it is perfectly okay and nearly
>>>> the same as their charger. I also contacted Battery Tender Jr. with the
>>>> reverse question and they said the BTJr is fine for LiFePO4. I used the BTJr
>>>> for years on my K2* with no issues. They're about $25 on internet sites.
>>>>
>>>
>>> Have you measured the amount of charge you're getting into the K2's?* It
>>> will be considerably less than the rated amount due to using a lead-acid
>>> charger.
>>>
>>> Also, if K2 has cell balancing capability, it won't be used because your
>>> Battery Tender doesn't put out enough voltage to make it work.
>>
>> Many simple lead-acid chargers reach up to around 14.2-14.8 volts.* That voltage
>> would suffice to charge an LFP battery to well above 90% capacity if it stays
>> there for a while.* If it quickly shifts to "float" at 13.5V or so then it won't
>> do well in charging LFP.* So simpler is better in this case.* Measure what your
>> charger does.* And disconnect it after several hours, don't leave it on "float".
>>
>
> Hate to break this to you, but at $24, the Battery Tender Junior is one of the
> cheapest chargers on the market, and is fully featured with a float mode.
>
> 14.2 volts wouldn't begin to charge an LFP to "well over 90%" as you claim.* If
> you found a charger that delivers 14.8 volts under load, then it would overcharge
> an SLA and would be considered defective.
>
> If you're going to spend big bucks for an LFP, you ought to get a proper charger
> for it.* Still waiting to hear just how much charge the K2's got in them from a BTJ.

Bienno Power has a $25, 12V/4A LiFePO4 charger. I'd trust that over a BT Jr, and
it's the same price.


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

[Richard Pfiffner[_2_]]

Craggy Aero has a 5A LiFePO4 Smart Charger

http://www.craggyaero.com/lifepo4_battery.htm

Richard

[Eric Greenwell[_4_]]

kinsell wrote on 11/13/2018 9:18 PM:
scinating videos on YouTube.
>>>
>>> However, "safer" isn't actually the same as "safe", LFP's are quite
>>> capable of burning, despite what the scholarly articles say.* There have
>>> been a number of fires, particularly when they're used as starter
>>> batteries.* High charge rates and very high discharge rates seem to
>>> cause problems, as homebuilders of small power planes have discovered.
>>> There was also that LFP battery fire in an EB-28 in Finland this summer.
>>>
>>> -Dave
>>
>> Dave, if you look around youtube long enough, you will find that a AAA battery
>> can make a fire. Certainly a 12V lead-acid has enough juice to do that if
>> circumstances are right. The overwhelming evidence of many years of usage of
>> LiFePo4 chemistry in glider batteries suggests that they are as safe as the old
>> gel-cells. Give progress a chance, I'm not saying be a Progressive.
>> Herb
>>
> If you come across a YouTube video of an AAA battery filling a cockpit with toxic
> smoke, you be sure to post the link, OK?
>
> Meanwhile, this is the sort of progress I can live without:
>
> https://www.pilotsofamerica.com/community/threads/aircraft-lithium-battery-fires.102016/

I did not see any indication the burning battery had a BMS. Some builders put in
the "starter" LiFe batteries that do not have a BMS, so perhaps that is the reason
the battery burned. I think LiFe batteries from the usual suppliers (Bienno, K2,
Stark - for example) with a BMS, used for instrument batteries, and charged with
the recommended charger are as safe as a comparable capacity SLA.


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

[Richard Pfiffner[_2_]]

On Friday, November 16, 2018 at 7:20:53 PM UTC-8, Eric Greenwell wrote:
> kinsell wrote on 11/13/2018 9:18 PM:
> scinating videos on YouTube.
> >>>
> >>> However, "safer" isn't actually the same as "safe", LFP's are quite
> >>> capable of burning, despite what the scholarly articles say.Â* There have
> >>> been a number of fires, particularly when they're used as starter
> >>> batteries.Â* High charge rates and very high discharge rates seem to
> >>> cause problems, as homebuilders of small power planes have discovered..
> >>> There was also that LFP battery fire in an EB-28 in Finland this summer.
> >>>
> >>> -Dave
> >>
> >> Dave, if you look around youtube long enough, you will find that a AAA battery
> >> can make a fire. Certainly a 12V lead-acid has enough juice to do that if
> >> circumstances are right. The overwhelming evidence of many years of usage of
> >> LiFePo4 chemistry in glider batteries suggests that they are as safe as the old
> >> gel-cells. Give progress a chance, I'm not saying be a Progressive.
> >> Herb
> >>
> > If you come across a YouTube video of an AAA battery filling a cockpit with toxic
> > smoke, you be sure to post the link, OK?
> >
> > Meanwhile, this is the sort of progress I can live without:
> >
> > https://www.pilotsofamerica.com/community/threads/aircraft-lithium-battery-fires.102016/
>
> I did not see any indication the burning battery had a BMS. Some builders put in
> the "starter" LiFe batteries that do not have a BMS, so perhaps that is the reason
> the battery burned. I think LiFe batteries from the usual suppliers (Bienno, K2,
> Stark - for example) with a BMS, used for instrument batteries, and charged with
> the recommended charger are as safe as a comparable capacity SLA.
>
>
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> - "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm
>
> http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

Several years ago I had a bad batch of batteries from one of the suppliers you mentioned in your post. 4 to 5 aH capacity in a 10 Ah battery. I quit selling them. I now sell LiFePO4 batteries that I personally test before shipping with a West Mountain Radio computer tester. Document is supplied with the battery.

http://www.craggyaero.com/lifepo4_battery.htm

Richard
www.craggyaero.com

[Eric Greenwell[_4_]]

Richard Pfiffner wrote on 11/17/2018 10:22 AM:
> On Friday, November 16, 2018 at 7:20:53 PM UTC-8, Eric Greenwell wrote:

>>> https://www.pilotsofamerica.com/community/threads/aircraft-lithium-battery-fires.102016/
>>
>>
>>>
I did not see any indication the burning battery had a BMS. Some builders put in
>> the "starter" LiFe batteries that do not have a BMS, so perhaps that is the
>> reason the battery burned. I think LiFe batteries from the usual suppliers
>> (Bienno, K2, Stark - for example) with a BMS, used for instrument batteries,
>> and charged with the recommended charger are as safe as a comparable capacity
>> SLA.
>>

>
> Several years ago I had a bad batch of batteries from one of the suppliers you
> mentioned in your post. 4 to 5 aH capacity in a 10 Ah battery. I quit
> selling them. I now sell LiFePO4 batteries that I personally test before
> shipping with a West Mountain Radio computer tester. Document is supplied with
> the battery.
>
> http://www.craggyaero.com/lifepo4_battery.htm

I test every battery before installing it, also using a West Mountain tester. Over
the years, I've had three SLA batteries that had half their rated capacity, and
returned them. I've only used one LiFe battery, and it had exactly the rated
capacity. Couldn't believe it - tested it again, and got the same answer.