SLA batteries opinions?

[john firth]

Recently I tested two 12v SLA s which had been in use
sequentially for some years usually recharged before going
going flat, or at least within one day.
Both were run down to 10.5 v with a 10 ohm load and then recharged to 14v,

The Yuasa 7 AH bought 2005 was good for about 2.5 AH
the UB 1280 8AH 6 years old good for < 2AH.
On this showing the Yuasa look like the better battery.
Both were used as panel supplies running at < .5 A load.

Any opinions on competing SLA batteries?

John F

[krasw]

maanantai 2. huhtikuuta 2018 20.14.19 UTC+3 john firth kirjoitti:
> Recently I tested two 12v SLA s which had been in use
> sequentially for some years usually recharged before going
> going flat, or at least within one day.
> Both were run down to 10.5 v with a 10 ohm load and then recharged to 14v,
>
> The Yuasa 7 AH bought 2005 was good for about 2.5 AH
> the UB 1280 8AH 6 years old good for < 2AH.
> On this showing the Yuasa look like the better battery.
> Both were used as panel supplies running at < .5 A load.
>
> Any opinions on competing SLA batteries?
>
> John F

Most (incl. Yuasa) specify battery life as 3-5 years. Glider use (deep cycles, low temps) means 3 years max in our experience. To get any amperage from 13 years old battery is nothing short of miracle.

[[email protected]]

In your test, did you measure the AH capacity in the discharge or the recharge? The latter is of course generally an overestimate.

The Yuasa had to be really well made to last THAT long! Half the life at half the cost may be OK too though. 6 years is not bad.

The practical life of an SLA mostly depends on how it is treated, not the manufacturing quality. I've seen our club's batteries go dead in less than 2 years. I think that's in part due to sometimes being left in a glider that it tied out, where it gets quite hot. I left a spare battery in my glider trailer for one season, it was then dead, again perhaps due to heat. Other than keeping them cool (but not cold), make sure to fully charge right after use (within a day or two anyway), using a good "smart" charger that will not overcharge it.

[Martin Gregorie[_6_]]

On Mon, 02 Apr 2018 12:11:30 -0700, moshe.braner wrote:

> In your test, did you measure the AH capacity in the discharge or the
> recharge? The latter is of course generally an overestimate.
>
> The Yuasa had to be really well made to last THAT long! Half the life
> at half the cost may be OK too though. 6 years is not bad.
>
> The practical life of an SLA mostly depends on how it is treated, not
> the manufacturing quality. I've seen our club's batteries go dead in
> less than 2 years. I think that's in part due to sometimes being left
> in a glider that it tied out, where it gets quite hot. I left a spare
> battery in my glider trailer for one season, it was then dead, again
> perhaps due to heat. Other than keeping them cool (but not cold), make
> sure to fully charge right after use (within a day or two anyway), using
> a good "smart" charger that will not overcharge it.

I do a fully charged - discharge - recharge cycle once a year on my
batteries (Yuasa NP7-12 SLAs) and sling them when they drop below 2/3 of
the capacity measured when they are new.

I use a cheapish multi-chemistry charger of the type sold for charging
and monitoring RC model batteries, so its good for round 0.4 amp charge
and discharge rates. Mine is a Pro-Peak Prodigy II sold in the UK by
Ripmax and is now several years old (12 at a guess). Similar charge/
discharge units will be available almost anywhere.


--
Martin | martin at
Gregorie | gregorie dot org

[Darryl Ramm]

That test is unlikeky to tell you anythibg useful about the battery quality.. If anything it might tell you how they are stored/abused. And storage/use/abuse is likelyvthe thing to worry about with SLA batteries,... they often get killed more than dying of old age.

Buy a good brand name SLA battery from a trusted/high volume dealer so it hopefully has a fresh manufacturing date and should arrive with a decent charge on it. Fully charge and then discharge test and write that date and tested current/capacity on the battery and repeat at every annual. The West Mountain Radio Computerized Battery Tester is a great investment, especially for clubs, FBOs, A&Ps etc. . When capacity gets to about 80% of spec (not initial measured capacity, which is likely higher) I would replace.

You may be better off using LiFePO4 batteries.

[[email protected]]

On Monday, April 2, 2018 at 4:29:49 PM UTC-4, Darryl Ramm wrote:
> You may be better off using LiFePO4 batteries.

Well I've been wondering about that each time I buy a new SLA and still find that I cannot justify the much higher cost of the LiFePO4 batteries (5x to 10x, depending on size, brand, etc). The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.

This depends also on how much capacity you need vs. the weight and volume needed to hold the battery(ies) in the glider. In my case my modest needs, in warm weather, are usually met by one 4AH SLA, and I can also use a 12AH when I want spare capacity (or a bit of ballast :-). If I had a fancier computer, plus transponder and FLARM, then the picture might be different, since the LiFePO4 can be discharged more deeply without damage while the SLA should only be taken to about half-full (and even when I test them I stop at about 11.5V).

[Darryl Ramm]

On Monday, April 2, 2018 at 4:16:45 PM UTC-7, wrote:
> On Monday, April 2, 2018 at 4:29:49 PM UTC-4, Darryl Ramm wrote:
> > You may be better off using LiFePO4 batteries.
>
> Well I've been wondering about that each time I buy a new SLA and still find that I cannot justify the much higher cost of the LiFePO4 batteries (5x to 10x, depending on size, brand, etc). The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.
>
> This depends also on how much capacity you need vs. the weight and volume needed to hold the battery(ies) in the glider. In my case my modest needs, in warm weather, are usually met by one 4AH SLA, and I can also use a 12AH when I want spare capacity (or a bit of ballast :-). If I had a fancier computer, plus transponder and FLARM, then the picture might be different, since the LiFePO4 can be discharged more deeply without damage while the SLA should only be taken to about half-full (and even when I test them I stop at about 11.5V).

I did say "may be better off". :-)

[krasw]

tiistai 3. huhtikuuta 2018 2.16.45 UTC+3 kirjoitti:
>The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.
>

In my experience lifetime of LFP is not better than SLA. My first battery died completely in 6 months, second had much reduced capacity after 2 seasons. Idea that chinese LFPs last thousand cycles or decade is just false.

[[email protected]]

On Monday, April 2, 2018 at 11:14:19 AM UTC-6, john firth wrote:
> Recently I tested two 12v SLA s which had been in use
> sequentially for some years usually recharged before going
> going flat, or at least within one day.
> Both were run down to 10.5 v with a 10 ohm load and then recharged to 14v,
>
> The Yuasa 7 AH bought 2005 was good for about 2.5 AH
> the UB 1280 8AH 6 years old good for < 2AH.
> On this showing the Yuasa look like the better battery.
> Both were used as panel supplies running at < .5 A load.
>
> Any opinions on competing SLA batteries?
>
> John F

Just for reference, 4.5 hrs on Duracell 9AH to drop to 10.5V. This is running everything including PF and TX. No more than 2 seasons use. I buy one every season from local high volume outlet (Around 25 bucks). Will occasionally use a smaller tail battery as well.
The biggest determinant of longevity is the charger. I have been using SLA for decades for soaring and other applications and for some reason I have been having a hard time finding good chargers lately. Used the PowerSonic chargers for years (No longer made) but sold these with my last ship. Have fried more than one battery when the charger did not detect peak and shut of (Or float) before the battery got hot. I have never measured it but this always results in a noticeable reduction in capacity.
3 years max (With the right charger) sounds about right. We are only talking 20 some odd bucks.

[2G]

On Monday, April 2, 2018 at 4:40:35 PM UTC-7, Darryl Ramm wrote:
> On Monday, April 2, 2018 at 4:16:45 PM UTC-7, wrote:
> > On Monday, April 2, 2018 at 4:29:49 PM UTC-4, Darryl Ramm wrote:
> > > You may be better off using LiFePO4 batteries.
> >
> > Well I've been wondering about that each time I buy a new SLA and still find that I cannot justify the much higher cost of the LiFePO4 batteries (5x to 10x, depending on size, brand, etc). The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.
> >
> > This depends also on how much capacity you need vs. the weight and volume needed to hold the battery(ies) in the glider. In my case my modest needs, in warm weather, are usually met by one 4AH SLA, and I can also use a 12AH when I want spare capacity (or a bit of ballast :-). If I had a fancier computer, plus transponder and FLARM, then the picture might be different, since the LiFePO4 can be discharged more deeply without damage while the SLA should only be taken to about half-full (and even when I test them I stop at about 11.5V).
>
> I did say "may be better off". :-)

I am switching to Odyssey batteries that use thin pure lead plates (PC680). Virtually all other SLA batteries are made with recycled lead, which is not pure (they claim 99.9%, but I doubt that is realistic - Odyssey guarantees 99.99% pure). They are designed for long life and severe environments.
http://www.odysseybattery.com/design_advantages.aspx
They are rated for deep discharge.

That said, I have had good luck with the Panasonic batteries that I have used in my ASH26e for 4 years, and recommend them for people on a budget.

Tom

[Darryl Ramm]

On Monday, April 2, 2018 at 10:51:03 PM UTC-7, wrote:
> On Monday, April 2, 2018 at 11:14:19 AM UTC-6, john firth wrote:
> > Recently I tested two 12v SLA s which had been in use
> > sequentially for some years usually recharged before going
> > going flat, or at least within one day.
> > Both were run down to 10.5 v with a 10 ohm load and then recharged to 14v,
> >
> > The Yuasa 7 AH bought 2005 was good for about 2.5 AH
> > the UB 1280 8AH 6 years old good for < 2AH.
> > On this showing the Yuasa look like the better battery.
> > Both were used as panel supplies running at < .5 A load.
> >
> > Any opinions on competing SLA batteries?
> >
> > John F
>
> Just for reference, 4.5 hrs on Duracell 9AH to drop to 10.5V. This is running everything including PF and TX. No more than 2 seasons use. I buy one every season from local high volume outlet (Around 25 bucks). Will occasionally use a smaller tail battery as well.
> The biggest determinant of longevity is the charger. I have been using SLA for decades for soaring and other applications and for some reason I have been having a hard time finding good chargers lately. Used the PowerSonic chargers for years (No longer made) but sold these with my last ship. Have fried more than one battery when the charger did not detect peak and shut of (Or float) before the battery got hot. I have never measured it but this always results in a noticeable reduction in capacity.
> 3 years max (With the right charger) sounds about right. We are only talking 20 some odd bucks.

BTW if an SLA battery charger does not switch to float, the first thing to suspect is the battery is faulty, a cell shorted or partially shorted... and then the charger being in bulk charge mode across the other cells for a long time will tend to evaporate out the small amount of electrolyte in the battery and kill it pretty fast. If it's happening in multiple batteries then obviously suspect the charger.

---

To everybody/more generally: using missized SLA/VRLA chargers can cause problem, the charger needs to be an SLA/VRLA charger, and should say the battery capacity they are designed for, ...or use around C/5 to C/10 bulk charge charge current (where C is the battery capacity in A.h). Too large a charger can damage the battery, too low a charger may never get to float mode and might fry the charger. Some chargers have temp sensors... you want them and the battery near each other and well ventilated. Solar chargers might put a surface charge on the battery but not actually much charge capacity. it's important to hammer the nail in with the right screwdriver :-)

[Tango Eight]

On Tuesday, April 3, 2018 at 1:47:02 AM UTC-4, krasw wrote:
> tiistai 3. huhtikuuta 2018 2.16.45 UTC+3 kirjoitti:
> >The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.
> >
>
> In my experience lifetime of LFP is not better than SLA. My first battery died completely in 6 months, second had much reduced capacity after 2 seasons. Idea that chinese LFPs last thousand cycles or decade is just false.

5 full seasons on a bioenno 12 AH LFP battery. 30 or 40 cycles a year to around half charge. It tested last week at 11.5 AH. Just my experience. Quite happy with it.

T8

[Dan Marotta]

I really liked seeing "ASH26e" and "budget" in the same sentence! :-D

On 4/2/2018 11:59 PM, 2G wrote:
> On Monday, April 2, 2018 at 4:40:35 PM UTC-7, Darryl Ramm wrote:
>> On Monday, April 2, 2018 at 4:16:45 PM UTC-7, wrote:
>>> On Monday, April 2, 2018 at 4:29:49 PM UTC-4, Darryl Ramm wrote:
>>>> You may be better off using LiFePO4 batteries.
>>> Well I've been wondering about that each time I buy a new SLA and still find that I cannot justify the much higher cost of the LiFePO4 batteries (5x to 10x, depending on size, brand, etc). The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.
>>>
>>> This depends also on how much capacity you need vs. the weight and volume needed to hold the battery(ies) in the glider. In my case my modest needs, in warm weather, are usually met by one 4AH SLA, and I can also use a 12AH when I want spare capacity (or a bit of ballast :-). If I had a fancier computer, plus transponder and FLARM, then the picture might be different, since the LiFePO4 can be discharged more deeply without damage while the SLA should only be taken to about half-full (and even when I test them I stop at about 11.5V).
>> I did say "may be better off". :-)
> I am switching to Odyssey batteries that use thin pure lead plates (PC680). Virtually all other SLA batteries are made with recycled lead, which is not pure (they claim 99.9%, but I doubt that is realistic - Odyssey guarantees 99.99% pure). They are designed for long life and severe environments.
> http://www.odysseybattery.com/design_advantages.aspx
> They are rated for deep discharge.
>
> That said, I have had good luck with the Panasonic batteries that I have used in my ASH26e for 4 years, and recommend them for people on a budget.
>
> Tom

--
Dan, 5J

[[email protected]]

On Monday, April 2, 2018 at 7:16:45 PM UTC-4, wrote:
> On Monday, April 2, 2018 at 4:29:49 PM UTC-4, Darryl Ramm wrote:
> > You may be better off using LiFePO4 batteries.
>
> Well I've been wondering about that each time I buy a new SLA and still find that I cannot justify the much higher cost of the LiFePO4 batteries (5x to 10x, depending on size, brand, etc). The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.
>
> This depends also on how much capacity you need vs. the weight and volume needed to hold the battery(ies) in the glider. In my case my modest needs, in warm weather, are usually met by one 4AH SLA, and I can also use a 12AH when I want spare capacity (or a bit of ballast :-). If I had a fancier computer, plus transponder and FLARM, then the picture might be different, since the LiFePO4 can be discharged more deeply without damage while the SLA should only be taken to about half-full (and even when I test them I stop at about 11.5V).

I just switched to lifepo4, got tired of killing SLA's. 5 to 10 times more expensive? Do you include the predicted lifetimes in that estimate? I paid $65 for my last 14 ah SLA and replaced it with lifepo4 for $130. So next year, or the year after, when I don't have to buy another SLA I'll be even? And I don't really have to worry about storage, running out of battery on a long flight, and the charge time is much less. With the new prices lifepo4 seems a no brainer to me. But I just bought it so we'll see.

[[email protected]]

On Tuesday, April 3, 2018 at 1:51:03 AM UTC-4, wrote:
> ... Have fried more than one battery when the charger did not detect peak and shut of (Or float) before the battery got hot.

Yes any time the battery gets hot it's bad for it. I've had batteries get hot sometimes when using a supposedly "smart" charger that was too small. Such a charger maintains a constant current until the voltage rises to something like 14.5V, and with too small a charge current relative to the size of the battery that may never happen. Alternatively the problem may be in the second stage, when the charger maintains a fairly high constant voltage and looks for the current to drop to, say, 5% of its capacity - with a 0.7A charger and a 12AH battery that may never happen. Sometimes I use a "dumb" charger that maintains a constant voltage of about 14V, that's safe (for a couple of days) but slow.

[[email protected]]

On Tuesday, April 3, 2018 at 10:54:21 AM UTC-4, wrote:
> I just switched to lifepo4, got tired of killing SLA's. 5 to 10 times more expensive? Do you include the predicted lifetimes in that estimate? I paid $65 for my last 14 ah SLA and replaced it with lifepo4 for $130. So next year, or the year after, when I don't have to buy another SLA I'll be even? ...

- I paid under $30 for my 12AH SLA, shipped. And when I bought 3 smaller SLAs (about 4 or 5 AH each) it was about $27 total for the 3, shipped (from apexbattery.com). Money wise I'm way ahead relative to LiFePO4. Would be nice to have the other advantages of LiFePO4 (no damage from deep discharge, better low temperature operation), but the price would have to drop by another factor of 2 to make sense for me.

[jfitch]

On Monday, April 2, 2018 at 10:47:02 PM UTC-7, krasw wrote:
> tiistai 3. huhtikuuta 2018 2.16.45 UTC+3 kirjoitti:
> >The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.
> >
>
> In my experience lifetime of LFP is not better than SLA. My first battery died completely in 6 months, second had much reduced capacity after 2 seasons. Idea that chinese LFPs last thousand cycles or decade is just false.

I going on my 5th season on the instrument LFP, it currently tests the same capacity as the label says. I generally replaced the SLA at 2 - 3 years as they had lost significant capacity by then. It cost 4x as much, or about the cost of two tows. To me the benefit of holding the voltage higher throughout the discharge cycle is worth that alone.

All batteries have a self destruct clock built in, ticking from the moment they leave the factory. SLA batteries have a shorter clock, but the thing that kills them is the use: deep discharge, followed by late recharge, followed by 6 months of idle storage. LFP batteries deal with this sort of thing MUCH better than SLA.

It's too early to tell if "chinese LFPs last thousands of cycles", but I know for a fact that Chinese LiPo batteries do, as I have a large number of devices that have. Chances are near 100% that if you are buying any lithium battery it was made in China. Chances are pretty good that if you buy an SLA it was made in China, too.

[[email protected]]

On Tuesday, April 3, 2018 at 11:44:49 AM UTC-5, jfitch wrote:
> On Monday, April 2, 2018 at 10:47:02 PM UTC-7, krasw wrote:
> > tiistai 3. huhtikuuta 2018 2.16.45 UTC+3 kirjoitti:
> > >The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.
> > >
> >
> > In my experience lifetime of LFP is not better than SLA. My first battery died completely in 6 months, second had much reduced capacity after 2 seasons. Idea that chinese LFPs last thousand cycles or decade is just false.
>
> I going on my 5th season on the instrument LFP, it currently tests the same capacity as the label says. I generally replaced the SLA at 2 - 3 years as they had lost significant capacity by then. It cost 4x as much, or about the cost of two tows. To me the benefit of holding the voltage higher throughout the discharge cycle is worth that alone.
>
> All batteries have a self destruct clock built in, ticking from the moment they leave the factory. SLA batteries have a shorter clock, but the thing that kills them is the use: deep discharge, followed by late recharge, followed by 6 months of idle storage. LFP batteries deal with this sort of thing MUCH better than SLA.
>
> It's too early to tell if "chinese LFPs last thousands of cycles", but I know for a fact that Chinese LiPo batteries do, as I have a large number of devices that have. Chances are near 100% that if you are buying any lithium battery it was made in China. Chances are pretty good that if you buy an SLA it was made in China, too.

Here is my admittedly radical view-point: Just like the Imperial System of distance and temp measurements and downwind dashes in gliders, the SLA battery belongs on the scrap heap of history. Get over it, boys and girls.

[Dan Marotta]

Now what's wrong with downwind dashes, Herb?Â* Is it that, if we don't do
it your way, we're wrong?Â* Lighten up.

On 4/3/2018 11:33 AM, wrote:
> On Tuesday, April 3, 2018 at 11:44:49 AM UTC-5, jfitch wrote:
>> On Monday, April 2, 2018 at 10:47:02 PM UTC-7, krasw wrote:
>>> tiistai 3. huhtikuuta 2018 2.16.45 UTC+3 kirjoitti:
>>>> The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.
>>>>
>>> In my experience lifetime of LFP is not better than SLA. My first battery died completely in 6 months, second had much reduced capacity after 2 seasons. Idea that chinese LFPs last thousand cycles or decade is just false.
>> I going on my 5th season on the instrument LFP, it currently tests the same capacity as the label says. I generally replaced the SLA at 2 - 3 years as they had lost significant capacity by then. It cost 4x as much, or about the cost of two tows. To me the benefit of holding the voltage higher throughout the discharge cycle is worth that alone.
>>
>> All batteries have a self destruct clock built in, ticking from the moment they leave the factory. SLA batteries have a shorter clock, but the thing that kills them is the use: deep discharge, followed by late recharge, followed by 6 months of idle storage. LFP batteries deal with this sort of thing MUCH better than SLA.
>>
>> It's too early to tell if "chinese LFPs last thousands of cycles", but I know for a fact that Chinese LiPo batteries do, as I have a large number of devices that have. Chances are near 100% that if you are buying any lithium battery it was made in China. Chances are pretty good that if you buy an SLA it was made in China, too.
> Here is my admittedly radical view-point: Just like the Imperial System of distance and temp measurements and downwind dashes in gliders, the SLA battery belongs on the scrap heap of history. Get over it, boys and girls.

--
Dan, 5J

[MNLou]

Yeah Herb - WTF? (Tony paid me to post this:))

Lou

[[email protected]]

On Tuesday, April 3, 2018 at 8:24:03 PM UTC-5, MNLou wrote:
> Yeah Herb - WTF? (Tony paid me to post this:))
>
> Lou

Flying downwind is for hang and para-gliders. We haven't done that in contests since the early 70's. But I do enjoy looking at Tony's excellent adventures now and then. Take note: if you disagree with me, that's fine. Just exercising my right to an opinion, that's all.

[Richard Pfiffner[_2_]]

On Monday, April 2, 2018 at 10:47:02 PM UTC-7, krasw wrote:
> tiistai 3. huhtikuuta 2018 2.16.45 UTC+3 kirjoitti:
> >The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.
> >
>
> In my experience lifetime of LFP is not better than SLA. My first battery died completely in 6 months, second had much reduced capacity after 2 seasons. Idea that chinese LFPs last thousand cycles or decade is just false.

In my experience LFP batteries are much better than SLA and deliver close to the label AH for many cycles. And if you drop them on your foot is does not hurt as bad.

Richard

Richard

[[email protected]]

I have flown with both an LFP and SLA battery in my ship for 5 years. I alternate which one is primary and which one is secondary on each flight. A PowerSonic 12V14Ah SLA vs Powerizer 12V15Ah LFP. With all my instruments running the SLA voltage drops below the minimum requirements of my radio by 5 hours. My LFP has never failed to power everything up to a 7 hour flight.. The SLA gets replaced after 3 years. My LFP is six years old and still working perfectly.

When I fly in very cold conditions (0C) the SLA is usually not driving my radio by three hours. Again, the LFP has run up to six hours without any significant voltage drop.

[Duster[_2_]]

Would you use any of the lithium batteries for initial hi current demand tasks such as electric pylon deployment and self-starter motors?

[Dan Daly[_2_]]

On Tuesday, April 3, 2018 at 11:05:18 PM UTC-4, wrote:
> I have flown with both an LFP and SLA battery in my ship for 5 years. I alternate which one is primary and which one is secondary on each flight. A PowerSonic 12V14Ah SLA vs Powerizer 12V15Ah LFP. With all my instruments running the SLA voltage drops below the minimum requirements of my radio by 5 hours. My LFP has never failed to power everything up to a 7 hour flight. The SLA gets replaced after 3 years. My LFP is six years old and still working perfectly.
>
> When I fly in very cold conditions (0C) the SLA is usually not driving my radio by three hours. Again, the LFP has run up to six hours without any significant voltage drop.

My microair 760 likes the higher voltage of the LiFePo, and I needed two 12V9Ah SLAs for long flights; never had to switch to back-up with LiFePo. I also like the faster charge, and the way the new batteries maintain charge.

[[email protected]]

On Tuesday, April 3, 2018 at 10:12:41 PM UTC-4, Richard Pfiffner wrote:
> On Monday, April 2, 2018 at 10:47:02 PM UTC-7, krasw wrote:
> > tiistai 3. huhtikuuta 2018 2.16.45 UTC+3 kirjoitti:
> > >The theoretical number of times the batteries of each type can be cycled is irrelevant if they will die of old age in a number of years, even if that's 10+ years for LiFePO4 and only 3-4 years for SLA in my use.
> > >
> >
> > In my experience lifetime of LFP is not better than SLA. My first battery died completely in 6 months, second had much reduced capacity after 2 seasons. Idea that chinese LFPs last thousand cycles or decade is just false.
>
> In my experience LFP batteries are much better than SLA and deliver close to the label AH for many cycles. And if you drop them on your foot is does not hurt as bad.
>
> Richard
>
> Richard

What if we want to drop it on Herb's foot?
Chris

[JS[_5_]]

As seen on a late night TV talk show: The top reasons for using SLA/AGM batteries in gliders.
.. As tail ballast.
.. To maintain the "cheap" glider pilot stereotype.
.. Wir haben es immer so gemacht.
Jim

[Dan Marotta]

I have to ask, then:Â* Why keep putting SLA batteries in your glider?Â* Do
you need them for weight and balance?Â* Why not just two LiFePO4?

My experience with the lithium batteries was nothing short of terrific.Â*
Prior to the switch, I couldn't power everything with two SLA batteries
for 5 hours (15 AH combined).Â* After switching (10 AH LFP), I never had
a shortage of power.

On 4/3/2018 9:05 PM, wrote:
> I have flown with both an LFP and SLA battery in my ship for 5 years. I alternate which one is primary and which one is secondary on each flight. A PowerSonic 12V14Ah SLA vs Powerizer 12V15Ah LFP. With all my instruments running the SLA voltage drops below the minimum requirements of my radio by 5 hours. My LFP has never failed to power everything up to a 7 hour flight. The SLA gets replaced after 3 years. My LFP is six years old and still working perfectly.
>
> When I fly in very cold conditions (0C) the SLA is usually not driving my radio by three hours. Again, the LFP has run up to six hours without any significant voltage drop.
>
>
>

--
Dan, 5J

[jfitch]

On Tuesday, April 3, 2018 at 8:16:30 PM UTC-7, Duster wrote:
> Would you use any of the lithium batteries for initial hi current demand tasks such as electric pylon deployment and self-starter motors?

I would (and do) use a properly spec'd LFP for that purpose. However saying so will start an epic chit fight on this thread like the other ones. So it would be best to live in the past and use whatever your copyright 1995 flight manual says to use. Don't do so unless you are familiar with all the issues and able to make a proper engineering call.

[john firth]

On Monday, April 2, 2018 at 1:14:19 PM UTC-4, john firth wrote:
> Recently I tested two 12v SLA s which had been in use
> sequentially for some years usually recharged before going
> going flat, or at least within one day.
> Both were run down to 10.5 v with a 10 ohm load and then recharged to 14v,
>
> The Yuasa 7 AH bought 2005 was good for about 2.5 AH
> the UB 1280 8AH 6 years old good for < 2AH.
> On this showing the Yuasa look like the better battery.
> Both were used as panel supplies running at < .5 A load.
>
> Any opinions on competing SLA batteries?
>
> John

The specs on the Dakota 12v 10 ah ($99) bats look good
Any experiences?

JMF

[Chris Rowland[_2_]]

A few things about SLA batteries.

The capacity is usually defined when discharged at the C/20 rate - so for a
7Ah battery 350 mA for 20 hours. The capacity at higher rates is reduced.
If you try to take 1.4A out of a 7Ah battery it won't last 5 hours.

I have found that if you treat them well they last well. Treating them
well means not to over discharge them, or overcharge them, and to recharge
them as soon as possible.

I have had good results with a simple constant voltage charger, charging to
13.6V. This seems to be enough to recharge them overnight. I've had
batteries last for 5 years or more.

The trick is to look at your energy budget, how much current do you need?
For a fairly simple system, a LX7007 (260 mA), a radio (200 mA) and a nav
device (200 mA), that's about 7 Ah in 10 hours. That lot should run off 2
7Ah batteries with no trouble. If you have higher demands then install
enough capacity that you only use 50% on the average day's flying.

The reservation about Lithium based batteries I have is their tendency to
catch fire. I realise that this depends on the chemistry and manufacture
but there have been enough instances of this that I'd be inclined to be
cautious unless the reduced mass and increased energy density is
essential.

And regardless of what chemistry your batteries use and what other things
are in place put a fuse in the battery lead close to the battery. All
batteries have enough capacity to produce an entertaining amount of acrid
smoke in the cockpit if you get a short.

Chris


At 14:40 04 April 2018, Dan Marotta wrote:
>I have to ask, then:Â* Why keep putting SLA batteries in your glider?Â* Do

>you need them for weight and balance?Â* Why not just two LiFePO4?
>
>My experience with the lithium batteries was nothing short of terrific.Â*

>Prior to the switch, I couldn't power everything with two SLA batteries
>for 5 hours (15 AH combined).Â* After switching (10 AH LFP), I never had
>a shortage of power.
>
>On 4/3/2018 9:05 PM, wrote:
>> I have flown with both an LFP and SLA battery in my ship for 5 years.
I
>alternate which one is primary and which one is secondary on each flight.

>A PowerSonic 12V14Ah SLA vs Powerizer 12V15Ah LFP. With all my
instruments
>running the SLA voltage drops below the minimum requirements of my radio
by
>5 hours. My LFP has never failed to power everything up to a 7 hour
>flight. The SLA gets replaced after 3 years. My LFP is six years old
and
>still working perfectly.
>>
>> When I fly in very cold conditions (0C) the SLA is usually not driving
my
>radio by three hours. Again, the LFP has run up to six hours without any
>significant voltage drop.
>>
>>
>>
>
>--
>Dan, 5J
>

[Richard Pfiffner[_2_]]

On Wednesday, April 4, 2018 at 11:24:19 AM UTC-7, john firth wrote:
> On Monday, April 2, 2018 at 1:14:19 PM UTC-4, john firth wrote:
> > Recently I tested two 12v SLA s which had been in use
> > sequentially for some years usually recharged before going
> > going flat, or at least within one day.
> > Both were run down to 10.5 v with a 10 ohm load and then recharged to 14v,
> >
> > The Yuasa 7 AH bought 2005 was good for about 2.5 AH
> > the UB 1280 8AH 6 years old good for < 2AH.
> > On this showing the Yuasa look like the better battery.
> > Both were used as panel supplies running at < .5 A load.
> >
> > Any opinions on competing SLA batteries?
> >
> > John
>
> The specs on the Dakota 12v 10 ah ($99) bats look good
> Any experiences?
>
> JMF

They are like all the 10Ah Chinese LiFePO4 batteries.
They Claim 10Amp but when tested with deliver 8 or 9 aH.

I just tested 2 K2 12V10Ah batteries for a customer use for several years. Tests results with a West Mountain Radio CBA IV 7.3 aH and 8.5 aH. My conclusion is they are not any better than the $99 12V9Ah batteries

Richard
www.craggyaero.com

[jfitch]

On Wednesday, April 4, 2018 at 12:00:07 PM UTC-7, Chris Rowland wrote:
> A few things about SLA batteries.
>
> The capacity is usually defined when discharged at the C/20 rate - so for a
> 7Ah battery 350 mA for 20 hours. The capacity at higher rates is reduced..
> If you try to take 1.4A out of a 7Ah battery it won't last 5 hours.
>
> I have found that if you treat them well they last well. Treating them
> well means not to over discharge them, or overcharge them, and to recharge
> them as soon as possible.
>
> I have had good results with a simple constant voltage charger, charging to
> 13.6V. This seems to be enough to recharge them overnight. I've had
> batteries last for 5 years or more.
>
> The trick is to look at your energy budget, how much current do you need?
> For a fairly simple system, a LX7007 (260 mA), a radio (200 mA) and a nav
> device (200 mA), that's about 7 Ah in 10 hours. That lot should run off 2
> 7Ah batteries with no trouble. If you have higher demands then install
> enough capacity that you only use 50% on the average day's flying.
>
> The reservation about Lithium based batteries I have is their tendency to
> catch fire. I realise that this depends on the chemistry and manufacture
> but there have been enough instances of this that I'd be inclined to be
> cautious unless the reduced mass and increased energy density is
> essential.
>
> And regardless of what chemistry your batteries use and what other things
> are in place put a fuse in the battery lead close to the battery. All
> batteries have enough capacity to produce an entertaining amount of acrid
> smoke in the cockpit if you get a short.
>
> Chris
>
>
> At 14:40 04 April 2018, Dan Marotta wrote:
> >I have to ask, then:Â* Why keep putting SLA batteries in your glider?Â* Do
>
> >you need them for weight and balance?Â* Why not just two LiFePO4?
> >
> >My experience with the lithium batteries was nothing short of terrific.Â*
>
> >Prior to the switch, I couldn't power everything with two SLA batteries
> >for 5 hours (15 AH combined).Â* After switching (10 AH LFP), I never had
> >a shortage of power.
> >
> >On 4/3/2018 9:05 PM, wrote:
> >> I have flown with both an LFP and SLA battery in my ship for 5 years.
> I
> >alternate which one is primary and which one is secondary on each flight..
>
> >A PowerSonic 12V14Ah SLA vs Powerizer 12V15Ah LFP. With all my
> instruments
> >running the SLA voltage drops below the minimum requirements of my radio
> by
> >5 hours. My LFP has never failed to power everything up to a 7 hour
> >flight. The SLA gets replaced after 3 years. My LFP is six years old
> and
> >still working perfectly.
> >>
> >> When I fly in very cold conditions (0C) the SLA is usually not driving
> my
> >radio by three hours. Again, the LFP has run up to six hours without any
> >significant voltage drop.
> >>
> >>
> >>
> >
> >--
> >Dan, 5J
> >

Please relate to us the stories (with backup links) about - specifically - LiFePo4 batteries catching fire in gliders - or other similar applications.

[Richard Pfiffner[_2_]]

John,

My experiences with LiFePO4

I have never heard of a LiFePO4 battery catching fire. I have had some customers connect reverse polarity. It burnt up the internal positive wire but the battery did not burn. I also just shorted a LiFePO4 12V10Ah turned it upside down and placed on a metal plate. It got hot and distorted the case near the contacts for the cells. It did not burn and was cool when I looked at it 1/2 hour later.

I had one supplier that gave me 24 Volt chargers by mistake. I charged one battery overnight and it got very large but did not catch fire.

Richard
www.craggyaero.com

[kinsell]

Wow. Didn't these batteries have a battery management system to prevent
damage?



On 04/04/2018 03:22 PM, Richard Pfiffner wrote:
>
>
>
> John,
>
> My experiences with LiFePO4
>
> I have never heard of a LiFePO4 battery catching fire. I have had some customers connect reverse polarity. It burnt up the internal positive wire but the battery did not burn. I also just shorted a LiFePO4 12V10Ah turned it upside down and placed on a metal plate. It got hot and distorted the case near the contacts for the cells. It did not burn and was cool when I looked at it 1/2 hour later.
>
> I had one supplier that gave me 24 Volt chargers by mistake. I charged one battery overnight and it got very large but did not catch fire.
>
> Richard
> www.craggyaero.com
>

[Chris Rowland[_2_]]

At 20:25 04 April 2018, jfitch wrote:
>On Wednesday, April 4, 2018 at 12:00:07 PM UTC-7, Chris Rowland wrote:

>> The reservation about Lithium based batteries I have is their tendency
to
>> catch fire. I realise that this depends on the chemistry and
manufacture
>> but there have been enough instances of this that I'd be inclined to be
>> cautious unless the reduced mass and increased energy density is
>> essential.
>
>Please relate to us the stories (with backup links) about - specifically
-
>=
>LiFePo4 batteries catching fire in gliders - or other similar
applications.
>

The more literate members of this forum will notice that I said "Lithium
based" and "this depends on the chemistry and manufacture".

A couple of links are:
http://ul-segelflug.de/images/stories/Downloads/dokumente/LiPo-Fire_AAIB_S3-2017_G-GSGS.pdf

and

https://assets.publishing.service.gov.uk/media/55effcaeed915d14f1000007/AAR_2-2015_Boeing_B787-8_ET-AOP_09-15.pdf

and

https://www.caa.co.uk/Commercial-industry/Airports/Safety/Dangerous-goods/Lithium-batteries/

An experiment to try is to short out a fully charged battery and see what
happens. Wait until everything is cool and think if you want to be around
it.

Chris

[Richard Pfiffner[_2_]]

On Wednesday, April 4, 2018 at 2:31:07 PM UTC-7, kinsell wrote:
> Wow. Didn't these batteries have a battery management system to prevent
> damage?
>
>
>
> On 04/04/2018 03:22 PM, Richard Pfiffner wrote:
> >
> >
> >
> > John,
> >
> > My experiences with LiFePO4
> >
> > I have never heard of a LiFePO4 battery catching fire. I have had some customers connect reverse polarity. It burnt up the internal positive wire but the battery did not burn. I also just shorted a LiFePO4 12V10Ah turned it upside down and placed on a metal plate. It got hot and distorted the case near the contacts for the cells. It did not burn and was cool when I looked at it 1/2 hour later.
> >
> > I had one supplier that gave me 24 Volt chargers by mistake. I charged one battery overnight and it got very large but did not catch fire.
> >
> > Richard
> > www.craggyaero.com
> >

I have found that BMS will not save a short.

Richard
www.craggyaero.com

[Darryl Ramm]

On Wednesday, April 4, 2018 at 1:25:55 PM UTC-7, jfitch wrote:
> On Wednesday, April 4, 2018 at 12:00:07 PM UTC-7, Chris Rowland wrote:
> > A few things about SLA batteries.
> >
> > The capacity is usually defined when discharged at the C/20 rate - so for a
> > 7Ah battery 350 mA for 20 hours. The capacity at higher rates is reduced.
> > If you try to take 1.4A out of a 7Ah battery it won't last 5 hours.
> >
> > I have found that if you treat them well they last well. Treating them
> > well means not to over discharge them, or overcharge them, and to recharge
> > them as soon as possible.
> >
> > I have had good results with a simple constant voltage charger, charging to
> > 13.6V. This seems to be enough to recharge them overnight. I've had
> > batteries last for 5 years or more.
> >
> > The trick is to look at your energy budget, how much current do you need?
> > For a fairly simple system, a LX7007 (260 mA), a radio (200 mA) and a nav
> > device (200 mA), that's about 7 Ah in 10 hours. That lot should run off 2
> > 7Ah batteries with no trouble. If you have higher demands then install
> > enough capacity that you only use 50% on the average day's flying.
> >
> > The reservation about Lithium based batteries I have is their tendency to
> > catch fire. I realise that this depends on the chemistry and manufacture
> > but there have been enough instances of this that I'd be inclined to be
> > cautious unless the reduced mass and increased energy density is
> > essential.
> >
> > And regardless of what chemistry your batteries use and what other things
> > are in place put a fuse in the battery lead close to the battery. All
> > batteries have enough capacity to produce an entertaining amount of acrid
> > smoke in the cockpit if you get a short.
> >
> > Chris
> >
> >
> > At 14:40 04 April 2018, Dan Marotta wrote:
> > >I have to ask, then:Â* Why keep putting SLA batteries in your glider?Â* Do
> >
> > >you need them for weight and balance?Â* Why not just two LiFePO4?
> > >
> > >My experience with the lithium batteries was nothing short of terrific..Â*
> >
> > >Prior to the switch, I couldn't power everything with two SLA batteries
> > >for 5 hours (15 AH combined).Â* After switching (10 AH LFP), I never had
> > >a shortage of power.
> > >
> > >On 4/3/2018 9:05 PM, wrote:
> > >> I have flown with both an LFP and SLA battery in my ship for 5 years..
> > I
> > >alternate which one is primary and which one is secondary on each flight.
> >
> > >A PowerSonic 12V14Ah SLA vs Powerizer 12V15Ah LFP. With all my
> > instruments
> > >running the SLA voltage drops below the minimum requirements of my radio
> > by
> > >5 hours. My LFP has never failed to power everything up to a 7 hour
> > >flight. The SLA gets replaced after 3 years. My LFP is six years old
> > and
> > >still working perfectly.
> > >>
> > >> When I fly in very cold conditions (0C) the SLA is usually not driving
> > my
> > >radio by three hours. Again, the LFP has run up to six hours without any
> > >significant voltage drop.
> > >>
> > >>
> > >>
> > >
> > >--
> > >Dan, 5J
> > >
>
> Please relate to us the stories (with backup links) about - specifically - LiFePo4 batteries catching fire in gliders - or other similar applications.

r.a.s. is powered by lithium.

[[email protected]]

On Wednesday, April 4, 2018 at 7:16:02 PM UTC-4, Darryl Ramm wrote:
> r.a.s. is powered by lithium.

- you mean the type that comes in pills? :-)

Regarding the other messages, I am surprised that the BMS does not protect from a short, I thought that was one of the stated protections officially promised. And that BMS was one major advantage of the (better) LiFePO4 batteries over SLA.

[[email protected]]

The Gliding federation in Australia has approved the Fusion lithium 10ah battery for use in place of SLA.
http://doc.glidingaustralia.org/index.php?option=com_docman&view=download&alias=2295-mtar-lifepo4-batteries-2017-08-01&category_slug=mosp-part-3-airworthiness&Itemid=101
Ive just got one, and am very happy with it so far.

[Richard Pfiffner[_2_]]

On Wednesday, April 4, 2018 at 5:06:53 PM UTC-7, wrote:
> On Wednesday, April 4, 2018 at 7:16:02 PM UTC-4, Darryl Ramm wrote:
> > r.a.s. is powered by lithium.
>
> - you mean the type that comes in pills? :-)
>
> Regarding the other messages, I am surprised that the BMS does not protect from a short, I thought that was one of the stated protections officially promised. And that BMS was one major advantage of the (better) LiFePO4 batteries over SLA.

What happens is a short is way over the 15 amp max discharge current and the battery is damaged and gets hot but the BMS shuts it down at 10V before it burns.

12V 9Ah
Voltage: 12V
Capacity: 9Ah
Chemistry: LiFePO
Weight: 2.8lbs (1.3kg)
Dimensions: 5.9"(L) x 2.6"(W) x 3.7"(H), [151mm(L) x 65mm(W) x95mm(H)
Life Cycles: 2,000 @ 80% DOD
BMS YES (Internal)
Max Charge Voltage: 14.6V
Discharge Cut-off Voltage: 10V
Max Charge Current: 9A
Max Discharge Current: 15A
Operating Temperature: -22°F to +140°F, (-30°C to +60°C)


Richard
www.craggyaero.com









Richard

[Eric Greenwell[_4_]]

Chris Rowland wrote on 4/4/2018 2:30 PM:
> An experiment to try is to short out a fully charged battery and see what
> happens. Wait until everything is cool and think if you want to be around
> it.
For a complete study of battery chemistries, you could also try shorting an SLA
battery. They can also cause problems, and that is one reason a fuse at the
terminals is so useful.

Anyone that intends to try the "short" should probably do a YouTube search first:
all the excitement without the fire, smoke, and destroyed battery.

--
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

[kinsell]

On 04/04/2018 04:04 PM, Richard Pfiffner wrote:
> On Wednesday, April 4, 2018 at 2:31:07 PM UTC-7, kinsell wrote:
>> Wow. Didn't these batteries have a battery management system to prevent
>> damage?
>>
>>
>>
>> On 04/04/2018 03:22 PM, Richard Pfiffner wrote:
>>>
>>>
>>>
>>> John,
>>>
>>> My experiences with LiFePO4
>>>
>>> I have never heard of a LiFePO4 battery catching fire. I have had some customers connect reverse polarity. It burnt up the internal positive wire but the battery did not burn. I also just shorted a LiFePO4 12V10Ah turned it upside down and placed on a metal plate. It got hot and distorted the case near the contacts for the cells. It did not burn and was cool when I looked at it 1/2 hour later.
>>>
>>> I had one supplier that gave me 24 Volt chargers by mistake. I charged one battery overnight and it got very large but did not catch fire.
>>>
>>> Richard
>>> www.craggyaero.com
>>>
>
> I have found that BMS will not save a short.
>
> Richard
> www.craggyaero.com
>

A good short should bring the terminal voltage below 10 volts instantly,
strange the BMS didn't kick in before damage occured.

Also a bood BMS ought to prevent overcharging , which clearly didn't
happen with the 24 volt chargers. If I had a battery swell in my
ASH-26E, it would cause some significant damage.

[jfitch]

On Wednesday, April 4, 2018 at 2:45:06 PM UTC-7, Chris Rowland wrote:
> At 20:25 04 April 2018, jfitch wrote:
> >On Wednesday, April 4, 2018 at 12:00:07 PM UTC-7, Chris Rowland wrote:
>
> >> The reservation about Lithium based batteries I have is their tendency
> to
> >> catch fire. I realise that this depends on the chemistry and
> manufacture
> >> but there have been enough instances of this that I'd be inclined to be
> >> cautious unless the reduced mass and increased energy density is
> >> essential.
> >
> >Please relate to us the stories (with backup links) about - specifically
> -
> >=
> >LiFePo4 batteries catching fire in gliders - or other similar
> applications.
> >
>
> The more literate members of this forum will notice that I said "Lithium
> based" and "this depends on the chemistry and manufacture".
>
> A couple of links are:
> http://ul-segelflug.de/images/stories/Downloads/dokumente/LiPo-Fire_AAIB_S3-2017_G-GSGS.pdf
>
> and
>
> https://assets.publishing.service.gov.uk/media/55effcaeed915d14f1000007/AAR_2-2015_Boeing_B787-8_ET-AOP_09-15.pdf
>
> and
>
> https://www.caa.co.uk/Commercial-industry/Airports/Safety/Dangerous-goods/Lithium-batteries/
>
> An experiment to try is to short out a fully charged battery and see what
> happens. Wait until everything is cool and think if you want to be around
> it.
>
> Chris

These incidents have nothing to do with LiFePo4 batteries. Plenty of fires from SLA batteries as well, which also have different chemistry.

Regarding a BMS - this is similar to saying "lithium battery". There is a wide variety of things called a BMS, some have overcharge and/or undercharge protection, some have cell balancing, some have high current disconnects, some have more than one, or all of these facilities.

Technology is getting more complicated these days folks. Let's not throw the baby out with the bathwater by terming it all "washing".

[Dan Marotta]

A fuse at the terminals is a necessary item, but that's not enough. Make
sure that the terminals are completely insulated against tossing
something metallic into the vicinity of the battery and having it fall
directly across the terminals.Â* The fuse won't help against that.

On 4/4/2018 9:36 PM, Eric Greenwell wrote:
> Chris Rowland wrote on 4/4/2018 2:30 PM:
>> An experiment to try is to short out a fully charged battery and see
>> what
>> happens.Â* Wait until everything is cool and think if you want to be
>> around
>> it.
> For a complete study of battery chemistries, you could also try
> shorting an SLA battery. They can also cause problems, and that is one
> reason a fuse at the terminals is so useful.
>
> Anyone that intends to try the "short" should probably do a YouTube
> search first: all the excitement without the fire, smoke, and
> destroyed battery.
>

--
Dan, 5J

[Richard Pfiffner[_2_]]

On Wednesday, April 4, 2018 at 10:16:45 PM UTC-7, kinsell wrote:
> On 04/04/2018 04:04 PM, Richard Pfiffner wrote:
> > On Wednesday, April 4, 2018 at 2:31:07 PM UTC-7, kinsell wrote:
> >> Wow. Didn't these batteries have a battery management system to prevent
> >> damage?
> >>
> >>
> >>
> >> On 04/04/2018 03:22 PM, Richard Pfiffner wrote:
> >>>
> >>>
> >>>
> >>> John,
> >>>
> >>> My experiences with LiFePO4
> >>>
> >>> I have never heard of a LiFePO4 battery catching fire. I have had some customers connect reverse polarity. It burnt up the internal positive wire but the battery did not burn. I also just shorted a LiFePO4 12V10Ah turned it upside down and placed on a metal plate. It got hot and distorted the case near the contacts for the cells. It did not burn and was cool when I looked at it 1/2 hour later.
> >>>
> >>> I had one supplier that gave me 24 Volt chargers by mistake. I charged one battery overnight and it got very large but did not catch fire.
> >>>
> >>> Richard
> >>> www.craggyaero.com
> >>>
> >
> > I have found that BMS will not save a short.
> >
> > Richard
> > www.craggyaero.com
> >
>
> A good short should bring the terminal voltage below 10 volts instantly,
> strange the BMS didn't kick in before damage occured.
>
> Also a bood BMS ought to prevent overcharging , which clearly didn't
> happen with the 24 volt chargers. If I had a battery swell in my
> ASH-26E, it would cause some significant damage.

The overcharging was a Stark Battery.

I will try the short on the famously expensive K2 battery today.

Standby for results.

Richard
www.craggyaero.com

[Tango Eight]

On Thursday, April 5, 2018 at 10:52:17 AM UTC-4, Richard Pfiffner wrote:
> On Wednesday, April 4, 2018 at 10:16:45 PM UTC-7, kinsell wrote:
> > On 04/04/2018 04:04 PM, Richard Pfiffner wrote:
> > > On Wednesday, April 4, 2018 at 2:31:07 PM UTC-7, kinsell wrote:
> > >> Wow. Didn't these batteries have a battery management system to prevent
> > >> damage?
> > >>
> > >>
> > >>
> > >> On 04/04/2018 03:22 PM, Richard Pfiffner wrote:
> > >>>
> > >>>
> > >>>
> > >>> John,
> > >>>
> > >>> My experiences with LiFePO4
> > >>>
> > >>> I have never heard of a LiFePO4 battery catching fire. I have had some customers connect reverse polarity. It burnt up the internal positive wire but the battery did not burn. I also just shorted a LiFePO4 12V10Ah turned it upside down and placed on a metal plate. It got hot and distorted the case near the contacts for the cells. It did not burn and was cool when I looked at it 1/2 hour later.
> > >>>
> > >>> I had one supplier that gave me 24 Volt chargers by mistake. I charged one battery overnight and it got very large but did not catch fire.
> > >>>
> > >>> Richard
> > >>> www.craggyaero.com
> > >>>
> > >
> > > I have found that BMS will not save a short.
> > >
> > > Richard
> > > www.craggyaero.com
> > >
> >
> > A good short should bring the terminal voltage below 10 volts instantly,
> > strange the BMS didn't kick in before damage occured.
> >
> > Also a bood BMS ought to prevent overcharging , which clearly didn't
> > happen with the 24 volt chargers. If I had a battery swell in my
> > ASH-26E, it would cause some significant damage.
>
> The overcharging was a Stark Battery.
>
> I will try the short on the famously expensive K2 battery today.
>
> Standby for results.
>
> Richard
> www.craggyaero.com

Need video :-).

T8

[Charlie M. (UH & 002 owner/pilot)]

Ohhhh......lots of videos online for RC types that had an issue. Many thousands of dollars (US) went up in smoke.

Most BMS protect for charge issues, most won't prevent direct shorts at the battery or battery to load. That is why we do other fuses.
Breakers are "fine", but you typically melt/burn stuff just before they trip.

Yes, some radios play dead before hurting a LA battery, thus some add a single cell to boost voltage.
Yes, LiFe batteries tend to have a flat curve until the end, thus radios (especially when transmitting) work until the ragged end.

Your radio may be dead, other electronics may still work....at least....until you key your mic.

[Richard Pfiffner[_2_]]

On Thursday, April 5, 2018 at 8:04:40 AM UTC-7, Tango Eight wrote:
> On Thursday, April 5, 2018 at 10:52:17 AM UTC-4, Richard Pfiffner wrote:
> > On Wednesday, April 4, 2018 at 10:16:45 PM UTC-7, kinsell wrote:
> > > On 04/04/2018 04:04 PM, Richard Pfiffner wrote:
> > > > On Wednesday, April 4, 2018 at 2:31:07 PM UTC-7, kinsell wrote:
> > > >> Wow. Didn't these batteries have a battery management system to prevent
> > > >> damage?
> > > >>
> > > >>
> > > >>
> > > >> On 04/04/2018 03:22 PM, Richard Pfiffner wrote:
> > > >>>
> > > >>>
> > > >>>
> > > >>> John,
> > > >>>
> > > >>> My experiences with LiFePO4
> > > >>>
> > > >>> I have never heard of a LiFePO4 battery catching fire. I have had some customers connect reverse polarity. It burnt up the internal positive wire but the battery did not burn. I also just shorted a LiFePO4 12V10Ah turned it upside down and placed on a metal plate. It got hot and distorted the case near the contacts for the cells. It did not burn and was cool when I looked at it 1/2 hour later.
> > > >>>
> > > >>> I had one supplier that gave me 24 Volt chargers by mistake. I charged one battery overnight and it got very large but did not catch fire.
> > > >>>
> > > >>> Richard
> > > >>> www.craggyaero.com
> > > >>>
> > > >
> > > > I have found that BMS will not save a short.
> > > >
> > > > Richard
> > > > www.craggyaero.com
> > > >
> > >
> > > A good short should bring the terminal voltage below 10 volts instantly,
> > > strange the BMS didn't kick in before damage occured.
> > >
> > > Also a bood BMS ought to prevent overcharging , which clearly didn't
> > > happen with the 24 volt chargers. If I had a battery swell in my
> > > ASH-26E, it would cause some significant damage.
> >
> > The overcharging was a Stark Battery.
> >
> > I will try the short on the famously expensive K2 battery today.
> >
> > Standby for results.
> >
> > Richard
> > www.craggyaero.com
>
> Need video :-).
>
> T8

Video shows nothing battery gets hot and cuts out at I suspect about 10V.

Richard
www.craggyaero.com

[kinsell]

On 04/04/2018 06:06 PM, wrote:
> On Wednesday, April 4, 2018 at 7:16:02 PM UTC-4, Darryl Ramm wrote:
>> r.a.s. is powered by lithium.
>
> - you mean the type that comes in pills? :-)
>
> Regarding the other messages, I am surprised that the BMS does not protect from a short, I thought that was one of the stated protections officially promised. And that BMS was one major advantage of the (better) LiFePO4 batteries over SLA.
>
>
The reason lithium batteries in all their flavors tend to have BMS
boards is that they are more sensitive to overcharge and overdischarge
problems. It's not good for SLA's to have that done to them, but but
they tolerate it much better than lithiums. Lithiums also generally
have problems with cell balancing, which is another task typically done
by the BMS. But you can't assume all bMS boards offer full protection,
RIchard's experiences tend to indicate otherwise.

For high-current batteries, disconnecting the terminals from the
internal cells is a tough problem, generally power transistors are used
to do the switching. Would you trust transistors to reliably handle the
current and voltage spikes created by a starter motor? I wouldn't.

[[email protected]]

You are confusing Lipo with with li ion, the modellers problems were with lithium polymer batteries, not the type we are discussing.

[jfitch]

On Thursday, April 5, 2018 at 10:20:48 AM UTC-7, Richard Pfiffner wrote:
> On Thursday, April 5, 2018 at 8:04:40 AM UTC-7, Tango Eight wrote:
> > On Thursday, April 5, 2018 at 10:52:17 AM UTC-4, Richard Pfiffner wrote:
> > > On Wednesday, April 4, 2018 at 10:16:45 PM UTC-7, kinsell wrote:
> > > > On 04/04/2018 04:04 PM, Richard Pfiffner wrote:
> > > > > On Wednesday, April 4, 2018 at 2:31:07 PM UTC-7, kinsell wrote:
> > > > >> Wow. Didn't these batteries have a battery management system to prevent
> > > > >> damage?
> > > > >>
> > > > >>
> > > > >>
> > > > >> On 04/04/2018 03:22 PM, Richard Pfiffner wrote:
> > > > >>>
> > > > >>>
> > > > >>>
> > > > >>> John,
> > > > >>>
> > > > >>> My experiences with LiFePO4
> > > > >>>
> > > > >>> I have never heard of a LiFePO4 battery catching fire. I have had some customers connect reverse polarity. It burnt up the internal positive wire but the battery did not burn. I also just shorted a LiFePO4 12V10Ah turned it upside down and placed on a metal plate. It got hot and distorted the case near the contacts for the cells. It did not burn and was cool when I looked at it 1/2 hour later.
> > > > >>>
> > > > >>> I had one supplier that gave me 24 Volt chargers by mistake. I charged one battery overnight and it got very large but did not catch fire..
> > > > >>>
> > > > >>> Richard
> > > > >>> www.craggyaero.com
> > > > >>>
> > > > >
> > > > > I have found that BMS will not save a short.
> > > > >
> > > > > Richard
> > > > > www.craggyaero.com
> > > > >
> > > >
> > > > A good short should bring the terminal voltage below 10 volts instantly,
> > > > strange the BMS didn't kick in before damage occured.
> > > >
> > > > Also a bood BMS ought to prevent overcharging , which clearly didn't
> > > > happen with the 24 volt chargers. If I had a battery swell in my
> > > > ASH-26E, it would cause some significant damage.
> > >
> > > The overcharging was a Stark Battery.
> > >
> > > I will try the short on the famously expensive K2 battery today.
> > >
> > > Standby for results.
> > >
> > > Richard
> > > www.craggyaero.com
> >
> > Need video :-).
> >
> > T8
>
> Video shows nothing battery gets hot and cuts out at I suspect about 10V.
>
> Richard
> www.craggyaero.com

Richard, try dropping a similar sized SLA on a metal plate.

[Richard Pfiffner[_2_]]

On Thursday, April 5, 2018 at 8:14:21 PM UTC-7, jfitch wrote:
> On Thursday, April 5, 2018 at 10:20:48 AM UTC-7, Richard Pfiffner wrote:
> > On Thursday, April 5, 2018 at 8:04:40 AM UTC-7, Tango Eight wrote:
> > > On Thursday, April 5, 2018 at 10:52:17 AM UTC-4, Richard Pfiffner wrote:
> > > > On Wednesday, April 4, 2018 at 10:16:45 PM UTC-7, kinsell wrote:
> > > > > On 04/04/2018 04:04 PM, Richard Pfiffner wrote:
> > > > > > On Wednesday, April 4, 2018 at 2:31:07 PM UTC-7, kinsell wrote:
> > > > > >> Wow. Didn't these batteries have a battery management system to prevent
> > > > > >> damage?
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> On 04/04/2018 03:22 PM, Richard Pfiffner wrote:
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> John,
> > > > > >>>
> > > > > >>> My experiences with LiFePO4
> > > > > >>>
> > > > > >>> I have never heard of a LiFePO4 battery catching fire. I have had some customers connect reverse polarity. It burnt up the internal positive wire but the battery did not burn. I also just shorted a LiFePO4 12V10Ah turned it upside down and placed on a metal plate. It got hot and distorted the case near the contacts for the cells. It did not burn and was cool when I looked at it 1/2 hour later.
> > > > > >>>
> > > > > >>> I had one supplier that gave me 24 Volt chargers by mistake. I charged one battery overnight and it got very large but did not catch fire.
> > > > > >>>
> > > > > >>> Richard
> > > > > >>> www.craggyaero.com
> > > > > >>>
> > > > > >
> > > > > > I have found that BMS will not save a short.
> > > > > >
> > > > > > Richard
> > > > > > www.craggyaero.com
> > > > > >
> > > > >
> > > > > A good short should bring the terminal voltage below 10 volts instantly,
> > > > > strange the BMS didn't kick in before damage occured.
> > > > >
> > > > > Also a bood BMS ought to prevent overcharging , which clearly didn't
> > > > > happen with the 24 volt chargers. If I had a battery swell in my
> > > > > ASH-26E, it would cause some significant damage.
> > > >
> > > > The overcharging was a Stark Battery.
> > > >
> > > > I will try the short on the famously expensive K2 battery today.
> > > >
> > > > Standby for results.
> > > >
> > > > Richard
> > > > www.craggyaero.com
> > >
> > > Need video :-).
> > >
> > > T8
> >
> > Video shows nothing battery gets hot and cuts out at I suspect about 10V.
> >
> > Richard
> > www.craggyaero.com
>
> Richard, try dropping a similar sized SLA on a metal plate.

I suspect a fire or at least a lot hotter.

Richard.