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

On 3/23/2018 5:35 PM, Jonathan St. Cloud wrote:
I have no idea why is was "bad". I just knew that every time I took glider
out of box fuse was melted. We checked the trailer top solar chargers with
controllers, they were fine as was solar charger and controller in glider.
One bad one out of bunch, replaced it no further problems.


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

On Friday, March 23, 2018 at 12:56:41 PM UTC-4, Jonathan St. Cloud
wrote:
Not a direct reply, but I took delivery of a brand new glider from
Schleicher that had one (out of four) bad LFP battery. All the
batteries are fused at the battery with circuit breaker on panel for
each instrument. Kept blowing fuses. Schleicher told me they had not
heard of a battery going bad, but quickly refunded monies to purchase a
new battery. No problems with new battery... Snip
Since this thread has drifted already...

....on the subject of "explaining battery 'badness'," ~2012 I encountered a
wet-cell SLA starter battery in a friend's car; it/she was suffering from
'intermittent/sudden deadness,' in the 'car won't start/suddenly quits
running' sense of things. Got lucky while troubleshooting, and noted the
battery's voltage suddenly halve (12.6-6.3V as I recall)...to eventually
return to 12.6V. Ultimately confirmed it started/ran-fine when DVM-showing
12.6V, and was 'quite silent' when the battery showed 6.3V (big surprise).
Since the battery was ~1yr-old from A-zone, I advised her to return it for a
new one (and don't take, "But it checks out OK on our tester," as an
acceptable - though quite possibly true - return-outcome).

Return accomplished; problem hasn't recurred in the years since then.

An EE brother said he'd never heard of such a failure (nor had AE-degreed I).

If it happens, it must be possible. 'Weird internal shorts,' weird internal
opens,' I wouldn't bet agin' either of 'em being possible...

Bob W.

---
This email has been checked for viruses by AVG.
http://www.avg.com

The point is batteries can burn, explode, catch fire... (even if there has never been a problem before) Keep that in mind if you change batteries and want to take a long flight on unproven batteries. From the MD500 POH, the only event you land immediately (even if over a forest according to factory pilots) is a battery run away (the only red button on the warning panel), I had one of those while flying. Ended up getting stalked by mountain lion. My batteries are double fused and each instrument has a breaker.


On Friday, March 23, 2018 at 5:00:00 PM UTC-7, BobW wrote:
On 3/23/2018 5:35 PM, Jonathan St. Cloud wrote:
I have no idea why is was "bad". I just knew that every time I took glider
out of box fuse was melted. We checked the trailer top solar chargers with
controllers, they were fine as was solar charger and controller in glider.
One bad one out of bunch, replaced it no further problems.


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

On Friday, March 23, 2018 at 12:56:41 PM UTC-4, Jonathan St. Cloud
wrote:
Not a direct reply, but I took delivery of a brand new glider from
Schleicher that had one (out of four) bad LFP battery. All the
batteries are fused at the battery with circuit breaker on panel for
each instrument. Kept blowing fuses. Schleicher told me they had not
heard of a battery going bad, but quickly refunded monies to purchase a
new battery. No problems with new battery... Snip
Since this thread has drifted already...

...on the subject of "explaining battery 'badness'," ~2012 I encountered a
wet-cell SLA starter battery in a friend's car; it/she was suffering from
'intermittent/sudden deadness,' in the 'car won't start/suddenly quits
running' sense of things. Got lucky while troubleshooting, and noted the
battery's voltage suddenly halve (12.6-6.3V as I recall)...to eventually
return to 12.6V. Ultimately confirmed it started/ran-fine when DVM-showing
12.6V, and was 'quite silent' when the battery showed 6.3V (big surprise)..
Since the battery was ~1yr-old from A-zone, I advised her to return it for a
new one (and don't take, "But it checks out OK on our tester," as an
acceptable - though quite possibly true - return-outcome).

Return accomplished; problem hasn't recurred in the years since then.

An EE brother said he'd never heard of such a failure (nor had AE-degreed I).

If it happens, it must be possible. 'Weird internal shorts,' weird internal
opens,' I wouldn't bet agin' either of 'em being possible...

Bob W.

---
This email has been checked for viruses by AVG.
http://www.avg.com

On Friday, March 23, 2018 at 8:48:40 AM UTC-7, jfitch wrote:
On Friday, March 23, 2018 at 3:43:18 AM UTC-7, Andrzej Kobus wrote:
On Friday, March 23, 2018 at 1:03:01 AM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 7:21:37 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 10:04:02 PM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 3:37:31 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 1:09:13 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 5:00:32 PM UTC-7, Andrzej Kobus wrote:
On Wednesday, March 21, 2018 at 7:18:52 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 12:12:31 PM UTC-7, Tango Eight wrote:
On Wednesday, March 21, 2018 at 2:15:26 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 10:22:48 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
While I usually don't disagree with you, if you READ what Tango8 posted, he is saying the same thing as you.
"Lithium in the name does make it the same", as I read it.

Your thoughts?!

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Let me remind you that most Apple products are produced in China, and they generally of high quality (maybe higher than they deserve, but that is a design issue, not a manufacturing one).

The ASH26e Maintenance Manual, section 2.8 states that EITHER the YUASA (or similar) or the Sonnenshein Dryfit A212 may be used. Nowhere does it say ONLY a gel cell battery is permissible. Speaking as an electrical engineer, I consider the Odyssey PC680 to be "similar" to the YUASA in form and function. The LiFePO4 definitely is not and should necessitate a 337 STC for certificated gliders like mine, not to say that it can't be done.

Tom

On Friday, March 23, 2018 at 12:34:11 PM UTC-7, Andrzej Kobus wrote:
On Friday, March 23, 2018 at 11:48:40 AM UTC-4, jfitch wrote:
On Friday, March 23, 2018 at 3:43:18 AM UTC-7, Andrzej Kobus wrote:
On Friday, March 23, 2018 at 1:03:01 AM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 7:21:37 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 10:04:02 PM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 3:37:31 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 1:09:13 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 5:00:32 PM UTC-7, Andrzej Kobus wrote:
On Wednesday, March 21, 2018 at 7:18:52 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 12:12:31 PM UTC-7, Tango Eight wrote:
On Wednesday, March 21, 2018 at 2:15:26 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 10:22:48 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
While I usually don't disagree with you, if you READ what Tango8 posted, he is saying the same thing as you.
"Lithium in the name does make it the same", as I read it.

Your thoughts?!

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

John, treat yourself to the last word on this subject because that what you need to feel better. You wore me out...

*** Exactly what failure mode are you concerned about?*** I'd like to know.....

A "cheap circuit getting overloaded" isn't very exact. I'm not sure what you are on about Chinese mass produced electronics, for example every modern commercial airliner has them saturated throughout all of their safety systems. Your own 31 has plenty of them running the fuel injection and ignition systems. The one you seem most concerned about is the high current disconnect, this can either fail open (engine won't start, never an emergency or a panic) or closed (exactly the state your SLA battery is stuck in).

Apparently you don't understand the physics of DC starter motors, which have a direct and inverse relationship between voltage applied and current drawn. As I said in the post you quote, the LPF battery held the voltage 3 volts higher at the starter than the SLA (11 vs. 8) and the current is proportionately less.

I have never advocated anyone using any battery they don't understand or are uncomfortable with - not in that thread and not in this one. I didn't bring it up in either thread. Particularly if you don't understand the issues or characteristics of different kinds of batteries, you should stick to what the book says, and let them do the thinking for you.

On Friday, March 23, 2018 at 10:21:56 PM UTC-7, 2G wrote:
On Friday, March 23, 2018 at 8:48:40 AM UTC-7, jfitch wrote:
On Friday, March 23, 2018 at 3:43:18 AM UTC-7, Andrzej Kobus wrote:
On Friday, March 23, 2018 at 1:03:01 AM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 7:21:37 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 10:04:02 PM UTC-4, jfitch wrote:
On Thursday, March 22, 2018 at 3:37:31 PM UTC-7, Andrzej Kobus wrote:
On Thursday, March 22, 2018 at 1:09:13 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 5:00:32 PM UTC-7, Andrzej Kobus wrote:
On Wednesday, March 21, 2018 at 7:18:52 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 12:12:31 PM UTC-7, Tango Eight wrote:
On Wednesday, March 21, 2018 at 2:15:26 PM UTC-4, jfitch wrote:
On Wednesday, March 21, 2018 at 10:22:48 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
While I usually don't disagree with you, if you READ what Tango8 posted, he is saying the same thing as you.
"Lithium in the name does make it the same", as I read it.

Your thoughts?!

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Let me remind you that most Apple products are produced in China, and they generally of high quality (maybe higher than they deserve, but that is a design issue, not a manufacturing one).

The ASH26e Maintenance Manual, section 2.8 states that EITHER the YUASA (or similar) or the Sonnenshein Dryfit A212 may be used. Nowhere does it say ONLY a gel cell battery is permissible. Speaking as an electrical engineer, I consider the Odyssey PC680 to be "similar" to the YUASA in form and function. The LiFePO4 definitely is not and should necessitate a 337 STC for certificated gliders like mine, not to say that it can't be done.

Tom

Tom, I can't post pictures but please read the sentence in the maintenance manual just above Types of Batteries. I quote it here directly and in its entirety: "Only mainentence-free lead-dry-gel batteries must be used as a power supply." The manual could hardly consider LiFePo4 batteries as they were invented after the manual was written.

Speaking as an electrical engineer, I consider the Odyssey PC680 to be significantly different than the Yuasa (short circuit current is twice as large for one, far greater than the capacity of any component in the circuit). But I'd have no problem using one even so. The battery I use is similar in form and function to the Yuasa, closer is specs than the PC680.

When I wanted to install LiFeP04 batteries in my 27, I asked the factory
and Uli Kramer's response was as follows:

"in principle we have approved these batteries with TN 2-2008 (attached):

“3. Parts not belonging to the Minimum Equipment

• Electric equipment and its aerials may neither in themselves nor by
their mode of operation
or by their effect upon the operating characteristics of the sailplane and
its equipment
constitute a hazard to safe operation.
Every electric equipment has to be checked for reciprocal influence by
systematically
turning off and on and operating all other instruments.
The equipment and its control and monitoring devices must be arranged so as
to be easily
controllable. Their installation must be such that they are sufficiently
ventilated to prevent
overheating.“


So a battery is also an electric equipment…..

Kind regards

Uli"

TN 2-2008 applies to all Schleicher gliders.

Jim

The ASH26e Maintenance Manual, section 2.8 states that EITHER the YUASA
(or=
similar) or the Sonnenshein Dryfit A212 may be used. Nowhere does it say
O=
NLY a gel cell battery is permissible. Speaking as an electrical
engineer,
=
I consider the Odyssey PC680 to be "similar" to the YUASA in form and
funct=
ion. The LiFePO4 definitely is not and should necessitate a 337 STC for
cer=
tificated gliders like mine, not to say that it can't be done.

Tom

You're too specific, ANY circuit will draw less current at a higher nominal voltage everything else being the same. Does not matter if AC, DC, single phase, multi phase.

As to battery rating, a marginally sized battery, when new, will age and give less ampacity. As the ampacity (sometimes shown as CA-cranking amps for starter batteries) the voltage will drop more causing more heating of wires.

As to wiring, the current rating (ampacity) is based on continuous current in free air, momentary higher amperages can be handled with no ill effects.
Enclosing the wire reduces the continuous current rating since it is no longer in free air.
This part of why a smaller wire can be used for starting and yet deal with the short term inrush current as the circuit is energized. Multiple start attempts WILL start to heat the wire.

No, I'm not an EE, many years in facilities doing wiring and 15 years working with large UPS batteries.

I did stay at a Holiday Inn Express a few times though. ;-)

On 3/23/2018 6:21 PM, Jonathan St. Cloud wrote:
Ended up getting stalked by mountain lion. My batteries are double fused and each instrument has a breaker.
Just another reason for always being armed while flying, as was required
by state law when I lived in Alaska.Â* And how do you double fuse a
battery, a switch to select one or the other?

I recall that the Saberliner 40 had the NiCd battery mounted in a lower
aft compartment which had the elevator control cables passing through.Â*
A battery overheat warning (read thermal runaway) was a no-****, get it
on the ground now, situation, or death would soon follow...
--
Dan, 5J

On 3/23/2018 6:21 PM, Jonathan St. Cloud wrote:
Ended up getting stalked by mountain lion.

Note to Tom... please add 'Catamount Evasion' to pre-solo training syllabus.

On Saturday, March 24, 2018 at 5:41:30 AM UTC-7, Charlie M. (UH & 002 owner/pilot) wrote:
You're too specific, ANY circuit will draw less current at a higher nominal voltage everything else being the same. Does not matter if AC, DC, single phase, multi phase.

As to battery rating, a marginally sized battery, when new, will age and give less ampacity. As the ampacity (sometimes shown as CA-cranking amps for starter batteries) the voltage will drop more causing more heating of wires.

As to wiring, the current rating (ampacity) is based on continuous current in free air, momentary higher amperages can be handled with no ill effects.
Enclosing the wire reduces the continuous current rating since it is no longer in free air.
This part of why a smaller wire can be used for starting and yet deal with the short term inrush current as the circuit is energized. Multiple start attempts WILL start to heat the wire.

No, I'm not an EE, many years in facilities doing wiring and 15 years working with large UPS batteries.

I did stay at a Holiday Inn Express a few times though. ;-)

Charlie, you are little too general . A resistor (or any resistive circuit such as light bulbs, etc.) WILL draw more current at higher voltage. Most electronics these days have internal switching supplies, and will draw less current as input voltage increases, i.e., constant power. A DC motor similarly does due to back EMF, except at stall where it is (mostly) a resistive device.

The thermal constant of the wire is greatly depended on by Schleicher and others for their starter wires. They are using PVC insulated wires (not Tezel) so 100 or perhaps 120 deg (it does not say). The wires run for several feet in a very tight bundle with a bunch of others, not free air. In the engine compartment, they may be operating at elevated ambient as well. All of these affect ampacity. But they are typically energized for only a few seconds. Ampacity for wire is stated for both free and bundled cases. "Momentary higher amperages can be handled" - yes, depending. If you short circuit a #6 with 1000 amps, "momentary" is going to be very momentary, one way or another! That is one of the advantages of a proper BMS in and LPF: it will disconnect the load if shorted to protect itself, protecting the wiring as a collateral benefit.

I am a degree carrying EE, that and $5 will get me a latte at Starbucks......