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Lithium-ion batteries important safety message

LiFePo4 batteries are good when maintained

LiFePo4 batteries are good when maintained properly. We're very used to "abusing" our lead-acid batteries. We can't treat the LiFePo4 batteries the same. They are very light, but need more attention than the old technology.

According to what I read in this report, this guy lost his aircraft, and almost his life, due to not maintaining his battery correctly.
 
LiFePo4 batteries are good when maintained properly. We're very used to "abusing" our lead-acid batteries. We can't treat the LiFePo4 batteries the same. They are very light, but need more attention than the old technology.

According to what I read in this report, this guy lost his aircraft, and almost his life, due to not maintaining his battery correctly.

By my initial read, it looks like he ran the battery to nothing (which these batteries don't like). He had continual problems with the battery after that, but did not address them. And then, in flight he experienced a high voltage (and presumably high current) alarm, but ignored it until he noticed fire.

I don't think the battery chemistry is the one to blame here.
 
That investigation was on "Lithium-ion" batteries. Which are a bad idea. But NOT "Lithium-iron" batteries which are the type gnerally sold for aircraft use. It is important to carefully read the last word of the description as they both begin with an "i".
 
That investigation was on "Lithium-ion" batteries. Which are a bad idea. But NOT "Lithium-iron" batteries which are the type gnerally sold for aircraft use. It is important to carefully read the last word of the description as they both begin with an "i".

This may be a problem with the report writer. Report says "lithium-ion phosphate" battery; which is not really a thing. "lithium-iron phosphate" is and I believe that is what Deltran lithium batteries are.
 
Looks like all Deltrain batteries sold today are "smart" batteries with overvoltage and overdrain built-in protection. No amount of abuse should have caused a thermal run-away.
 
Looks like all Deltrain batteries sold today are "smart" batteries with overvoltage and overdrain built-in protection. No amount of abuse should have caused a thermal run-away.

I seem to remember, in the article, that he had hooked up some kind of external charger (presumably a battery-powered jumpstarter of some sort) and left it hooked up to the aircraft battery to prevent it from "losing charge" during the flight. Perhaps it was hooked up in a way that prevented the battery's over-voltage protections from working...?
 
The pilot in this case was an experienced aviator, aircraft builder and senior police officer - I can sympathise with his predicament, particularly given that alternative chemistry batteries are so often portrayed as a ?direct replacement? for lead acid, with little emphasis on the safety risk. We are still learning the hard way that that?s not entirely true and you really do need to read the fine print and do some things differently.
 
EarthX batteries

I'm posting this info with permission from my son who posted this message on the canard/vari-eze forum and got the response shown at the end....

So....

I will no longer be using EarthX batteries in the foreseeable future in any of my aircraft.

I've purchased 4 batteries (about $2,000 in total). Of those 4, only the one currently installed in my VariEze is in actual use and I'm planning to remove and replace it at the next major inspection if not sooner.

Why?
Unreliable: I've had three failures in 4 batteries, all different types of failures, all with less than a year of service.
Expensive: The value to cost ratio isn't there. They are at least 10-20 times the cost of functionally equivalent batteries with the only benefit being a 7-9 lb weight savings.
Dangerous: The materials these batteries are made of can potentially ignite in-flight. They are considered hazmat so shipping is more expensive and one-way only. You can't send them back in the mail, only ground freight with hazmat labeling (gouge $$$ opportunity). If the post office won't take them, why should I carry one in my plane??!
Factory support: EarthX wasn't interested in analyzing the failures of my batteries. They blamed the failures on my improper handling. In once case, I can say I charged it with an improper charger. But one battery was lightly used for a month, then stored fully charged and in less than a year it was a useless poundcake when I tried to bring it back into service.
Cold weather limitations: In my experience, these batteries perform poorly at low temps and capacity is 10%-15% lower when cold. It's similar to leadacid batteries, but circut protection prevents deep discharge, which can leave you stranded on a cold ramp. The manual provides detailed specifications on cold weather operations, but I have suspicions the documented numbers are not consistent with real-world performance.
Complexity of Operation: These batteries are picky about what charging system is used and come with a 32 page operators manual. ETX hundred series variants require a special monitoring circuit to be installed (increased complexity of installation).
Premature power cutoff - These batteries have a protection circuit that cuts the power before the cells are completely depleted. If I'm in an emergency situation, this safety system cannot be overridden therefore the energy cannot be tapped. Not acceptable for me since I'm totally ok sacrificing a battery in an emergency situation. If my alternator fails, then I'm on battery only. If the battery shuts off because it's getting low, then I lose ignition. I therefore have to install a secondary battery to protect my ignition...and all the complexity that comes with that....I simply can't trust the battery to operate when the plane loses the alternator.
I'm not opening a debate, I'm simply sharing my opinion and my decision. I think these batteries are ok for some other applications, like motorcycles or perhaps less electrically dependent aircraft that can have the battery installed on the engine side of the firewall, but I'm ready to ditch them for the old lead acid batteries. I don't want this little bomb at my feet anymore ready to burn my canard in half.

Subject: Re: [c-a] EarthX - Final Report

?...if you're comfortable enough holding a cordless 18V drill in your hand without worrying about your arm being blown to pieces, you shouldn't be that scared about putting these in a Long-EZ....?

You can put the screwdriver down if it catches fire. When the battery is at your feet and up under the Canard and your cruising at 10,000? when it ?goes off? things will get a little more intimate...so I gotta disagree with that statement.



Izzy
 
Once you hit either the melting temperature of the plate separators, or the melting temperature of the lithium, the demons come out and no external fuse or other gizmo will stop it. If you've ever seen a thermal runaway, you certainly come away "impressed".

Only way I would have a lithium based main battery in my plane would be if it was in a stainless steel box with a vent pipe to the outside large enough to handle the volume of gas generated in a thermal runaway.

I have seen two "oh they won't TR" battery tests that resulted in the lab being closed afterward for a couple weeks while they cleaned up and installed armored glass to protect the test technicians, and another that blew the video camera tripod over in the test cell due to an "energetic event". (overpressue due to inadequate vent because "it can't happen"). Uh huh... kind of like Elon Musk's comment about "an unplanned disassembly of parts..."
 
Good to See New Technology, Always a Price to Pay!

Messed around with LI-PO batteries before they became LI-ion etc.. (RC electric aircraft models.)

This was before charging protection was available. Only way to charge back then was when they were inside a "Battery Bunker". Ceramic urn designed to handle the runaway fire. Back then it was said the fire reached over 2600 deg C.

There is now way I would have one in an airplane, bad enough carrying a cell phone around.

When I fly, I have a homemade battery bunker. Bought ceramic fabric from Mcmaster Carr, used stainless steel wire to "sew" the edges. The fabric has an 800 deg F per hour burn through rating. So I doubled the fabric.

Always like seeing new technology, however, will not use a LI-anything where I can't physically control the device. Recently going through some of my RC stuff, found the bunker I used to use. Now it is kept in my Rv for cell phones.

Best regards,
Mike Bauer
 
Surprising you only have cell phones on board that have Li-Ion batteries. Most folks probably have more. If I'm flying solo, I have these Li-Ion devices (of whatever chemistry) on board. The first four are connected to ship's power, so I'm hoping the built-in charging protection safeguards always work.

- Dynon backup battery
- Garmin AERA 660
- Garmin GDL 50
- iPad Mini 4
- iPhone 7
- Canon camera

If a passenger comes along, then there are usually additional Li-Ion powered devices.

The risks are low, but the consequences are high. But, so far so good.

I am not really sure what the real risk potential is with the newer technology. However, the chemical energy potential of your lithium battery for the aircraft is MANY orders greater than a cell phone. Think of dropping a cigarette in a small saucer filled with gasoline vs dropping one in your gas tank. Further, your cell phone isn't connect to a charging device capable of producing 60 amps and device drains exceeding 200 amps. Cell phone batteries are protected by sophisticated electronic circuits that simply don't exist in your plane. Now, some of these batteries are beginning to incorporate that circuitry. However, I believe there is still a ways to go in perfecting them. Just ask the guy here, who lost a LOT of electronics when he had an overvoltage and the lihium battery cut it self off from the circuit, causing a massive voltage spike.

Larry
 
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Risk management

The fuel we carry in our aircraft has a lot more energy than the battery, and we manage and accept that risk. What's wonderful is that we can each make the right choice for our aircraft.
 
Don't put your battery in the cockpit side of Firewall

I've been trying to keep my nose out of this for 3 years now and haven't said much about it, certainly never posted about it. I'm still not going to bad mouth any company or their products. I'm simply going to post this and let you make your own decisions. Buy the battery you think is right for your mission but for God sakes, place it on the engine side of the firewall. 3 years ago on a flight back from purchasing a different airplane, one of my dearest friends had a very close call because this happened on take-off about 200 feet in the air. There was an immediate turn around, landed on the grass and evacuated. The purple smoke was unbearable, certainly not breathable. The battery literally melted, dripping goo but thankfully no fire because he shut down all power immediately. If he had been another 1000 feet or higher, he doesn't know if he would have made it down alive.

Again, buy the cool new technology, I'm all about that but in the case of a battery, don't put them in the cabin.


 
I've been trying to keep my nose out of this for 3 years now and haven't said much about it, certainly never posted about it. I'm still not going to bad mouth any company or their products. I'm simply going to post this and let you make your own decisions. Buy the battery you think is right for your mission but for God sakes, place it on the engine side of the firewall. 3 years ago on a flight back from purchasing a different airplane, one of my dearest friends had a very close call because this happened on take-off about 200 feet in the air. There was an immediate turn around, landed on the grass and evacuated. The purple smoke was unbearable, certainly not breathable. The battery literally melted, dripping goo but thankfully no fire because he shut down all power immediately. If he had been another 1000 feet or higher, he doesn't know if he would have made it down alive.

Again, buy the cool new technology, I'm all about that but in the case of a battery, don't put them in the cabin.



Do you know which model Earth X battery this was? Did it have the BMS?
 
Mark, I don't know the exact model and I don't think it had BMS. Again, for those reading this post, I'm NOT saying don't buy one brand over another. I'm simply saying that when you put your battery in the cabin, know that something like this may happen. Who's to say that an electronic board designed to control overcharging doesn't get fried. In the 30+ years that I've been in the technology field, ALL manufactures have had some sort of failure. I've seen Computers melt, I've seen switches and routers cause massive datacenter fires, I've seen cell phones combust for no reason, I've seen RC LIPO batteries burn homes to the ground, I've seen $120K Teslas catch on fire and many many more examples. My point here is that ANY technology can fail. I'm not picking on any of them. We are all taking risks on a daily basis and if we can mitigate risk just a little, we should certainly think about it. Even my own plane with the new upgraded panel, I have a backup battery that can combust but I'm accepting that risk. Do I want to put another battery in the cabin? No, I personally don't.
 
...and

...and consider the fact that placing the battery on the hot side of the firewall may become a contributing factor to lithium battery failure.

They are great batteries, as long as they are properly cared for. Can a properly cared for lithium battery fail? Absolutely, but as a previous posts has stated, all things cans fail...I have personal experience with a Lead-acid battery that exploded and sprayed acid all over the place...
 
NASA has spent a lot of time analyzing ways to mitigate risks associated with Lithium ion batteries. I don?t have access to those links now but they should be available to those interested in finding them.
 
.
... Buy the battery you think is right for your mission but for God sakes, place it on the engine side of the firewall. ...
...Again, buy the cool new technology, I'm all about that but in the case of a battery, don't put them in the cabin....

Sorry, but I could not agree less with these sentiments- placing any battery forward of the firewall is a bad idea, and a LiFePo battery would be no happier there than you would.

An intelligent response to potential and experiential problems by EarthX has resulted in exactly one battery so far, the EXT900-VNT, specifically designed for installation in the passenger cabin, being available for exprimentals now and hopefully soon for certified aircraft as well. It includes a sophisticated BMS, a sealed containment vessel, and dual vents for overboarding noxious gasses in the event of a thermal runaway. Yes, it costs significantly more than any among the plethora of bargain-basement offerrings now available. Get over it- do the right thing and budget for it. This technology has compelling benefits, but it is NOT a good place to economize.

I’m installing two of them in the cabin of my RV now, configured as a symmetrical, twin-redundant system, fed by a single spline-drive B&C BC462-H alternator with a crowbar-protected B&C regulator capable of 45Amps output, custom installed for its own protection(see:
http://www.vansairforce.com/community/showthread.php?t=159331&highlight=Spline-drive ) This is another bad place for economizing. Fault-LED’s and dedicated volt-meters for both batteries will be prominantly located front and center above my EFIS, and an OV warning light for the charging system not far away.

Inexpensive mass-marketed miracle devices have led us to expect all technology to be cheap. Don’t fall into that expectations trap for critical aircraft systems. -Otis
 
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I understand that one thing regarding lithium batteries and their installation in our airplanes is universally agreed now is that external overvoltage (crowbar) protection is required regardless of absence or presence of a built-in BMS. The built-in BMS will fail at higher voltages and cannot be relied on.
 
I understand that one thing regarding lithium batteries and their installation in our airplanes is universally agreed now is that external overvoltage (crowbar) protection is required regardless of absence or presence of a built-in BMS. The built-in BMS will fail at higher voltages and cannot be relied on.

That is not an absolute truth. The built-in BMS in EarthX batteries, for example, is designed to disconnect incoming voltages at 16 volts. Saying it "will fail at higher voltages" is an assumption on your part, not supportable as a blanket statement.

EarthX has come out publicly making some sort of external voltage regulation a requirement, and for good reason. As they say, one should never solely rely on the BMS to protect your battery, and that BMS voltage protection was never meant to protect the other aircraft components (avionics, etc).
 
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Let's back up a moment...

This conversation is spiraling into directions that simply aren’t supported by the original report, which itself has some problems. In the defense of actual LiFePo4 Lithium Iron Phosphate batteries, and our good friends at EarthX (who are on the road and can’t respond), I ask everyone to consider the following:

1) The report said the battery was a Deltran 330 Lithium-ion Phosphate battery. The Deltran 330 is not a lithium battery. It’s constructed with lead calcium alloy and absorbed glass mat technology. By the way, this isn’t even an aircraft battery: It’s for motorcycles, go-carts, and the like. http://products.batterytender.com/Batteries/12V-20Ah-330CCA-AGM-Engine-Start-Battery.html

2) For some reason, the report also discusses Lithium Ion Phosphate and Lithium Ion batteries. Folks, every “lithium” battery of every chemistry type is some sort of lithium ion battery, but which one? Saying you have a lithium battery is like simply saying you fly an airplane. There are so many different types on the market.

3) NOWHERE in the report do they mention the phrase “Lithium Iron Phosphate” or LiFePo4, or EarthX for that matter. How did that get into this discussion? The EarthX is a LiFePO4 battery, a state-of-the-art aircraft battery that is hugely trustworthy, even about to get FAA certification if it hasn’t happened already.

4) LiFePo4 batteries are like EVERY OTHER form of battery produced, including lead-based and NiCad batteries: If you overheat it, you’ll have some sort of thermal event. However, LiFePO4 batteries are not the type of “lithium ion batteries” that explode in our iPhones, vape Ecigs, or other newsworthy consumer items: Those are Lithium Cobalt Oxide (see? another ion). If overheated, LiFePo4 batteries can smoke A LOT, but they don’t explode, and certainly don’t shower the area with lead acid.

5) In addition, most anyone who has actually bought and installed an EarthX battery (or any other lithium type) will have read in the documentation that depleting the battery’s charge RUINS the battery. Then, continued attempts to charge it can induce this sort of thermal event. That’s why the EarthX has dual battery management system (BMS) computers that disconnect the battery internally at around 95% depletion, preventing this very sort of hazard while preserving the battery. Cheaper non-aviation non-EarthX lithium batteries don’t have this protection. You get what you paid for.

6) The report clearly describes a pilot/owner who had no idea what was on his aircraft, and just as clearly had brutally abused his battery and charging system. I hardly fault the poor Lead Calcium Alloy battery for the resulting fire, but I also acknowledge he probably would have had a similar event if he had flown a non-aviation lithium battery. No wonder he suffered this event. He’s lucky to be alive.

I urge y’all to go to EarthX’s site and read up: https://earthxbatteries.com/ . I absolutely love my EarthX ETX900 battery. I have it mounted on the firewall forward, with EarthX’s thermal battery box and a scat blast tube carrying cool air from the engine baffle back wall (keeps it cool). Yes, my warning light is installed. It is a POWERFUL and dependable battery. I currently charge it inflight with a PlanePower internally-regulated alternator, but am switching to a B&C 60amp and external voltage regulator.

With all the cost-savings measures we RV builders try to employ, DO NOT SKIMP on your battery choice. For all the reasons discussed in this thread, be sure to select a real battery for real aviation purposes. Please look past the boogey man: EarthX LiFePo4 is a safe and solid choice if you install it right and treat it right.
 
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That is not an absolute truth. The built-in BMS in EarthX batteries, for example, is designed to disconnect incoming voltages at 15.9 volts. Saying it "will fail at higher voltages" is an assumption on your part, not supportable as a blanket statement.

EarthX has come out publicly making some sort of external voltage regulation a requirement, and for good reason. As they say, one should never solely rely on the BMS to protect your battery, and that BMS voltage protection was never meant to protect the other aircraft components (avionics, etc).

Please read what EarthX rep admitted in the above referenced threat ? the BMS overvoltage protection will fail at around 60 volts and that is what apparently happened at the failure that was discussed there. When they say that the BMS kicks in at 15.9 volts is misleading at best... So, at 15.9V the battery takes itself offline and let the alternator fry everything else, including, once 60V is reached, its BMS, the the battery goes up in smoke.... Hence, you absolutely need real OV protection. So, I call this BMS a marketing BS and nothing else. You may as well go with a lithium battery wih no BMS, if you insist on going with a lithium battery.
 
Please read what EarthX rep admitted in the above referenced threat — the BMS overvoltage protection will fail at around 60 volts and that is what apparently happened at the failure that was discussed there. When they say that the BMS kicks in at 15.9 volts is misleading at best... So, at 15.9V the battery takes itself offline and let the alternator fry everything else, including, once 60V is reached, its BMS, the the battery goes up in smoke.... Hence, you absolutely need real OV protection. So, I call this BMS a marketing BS and nothing else. You may as well go with a lithium battery wih no BMS, if you insist on going with a lithium battery.

Kalibr,
You are correct, and I acknowledge that my comment was incomplete regarding the 60V BMS failure point. You and I agree with the absolute need for real overvoltage protection.

However, the 16V initial BMS disconnect comes straight from the EarthX folks and manual (I incorrectly cited this as a 15.9V limit). If incoming voltage hits/exceeds 16V, the BMS is designed to disconnect. Then, as you said, if voltage continues to climb to at/above 60V, BMS basically gets overwhelmed.

From the EarthX manual:
"In the event of a charging system failure where the voltage increases to above 15.5V, the resistance to charging current increases, and above 16V the charging current is completely blocked. The time delay for this feature is 1 second to allow the aircraft alternator’s over voltage protection (crowbar circuit) to activate first. This design offers charge voltage protection greater than 40V. The discharge current (current out of battery) is unaffected in this situation. EarthX requires having automatic over-voltage protection (crowbar) for alternator type charging systems (not required for <20 Amp pad mount standby alternators)."

These conditions are beautifully discussed in Kathy's thread: www.vansairforce.com/community/showthread.php?t=154137
 
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Scroll, thank you for the precise reference and the link to the more specific thread on the subject matter. In that thread, unfortunately, one issue remained unanswered ? why the EarthX?s position that OV protection is not required for systems with alternators rated for less than 20 amps. I had an impression that a small alternator may very well make more than 60v with a faulty regulator and will be just as deadly.
 
Good question. That?s not my setup, so I don?t know.
I do know that Kathy and her EarthX gang will respond soon: I?ll leave it up to the experts to answer.
 
Over Voltage Protection

If you want to make sure you have a good additional way to protect any overvoltage situation from happening instead of only relying on a BMS system then using these units used with the best alternators,IMO, http://www.bandc.aero/alternatorcontrollerregulator14vhomebuilt.aspx provide a good alternative. That’s what I now use due to the issues some of my customers have had with another brand ;)
 
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This may answer the question:

http://www.vansairforce.com/community/showpost.php?p=1210545&postcount=27

"Q: So what's different about lithium iron chemistry that makes it able to handle a 20 amp alternator in an overvoltage situation, but not handle a 30 amp alternator in the same situation, meaning the same level of over-*voltage*?

A: Our manual may be causing the confusion when we say over-voltage protection is not required on ?<20 Amp pad mount standby alternators?. The confusion is that it has nothing to do with it being a < 20 amp alternator. The real reason is the ?pad mount standby alternator?, for a pad mount alternator RPM is much lower and as such the unregulated voltage (in the event of a regulator failure) will be much lower. Low enough that Earth?x BMS can block any charge current at those voltages.
"

I missed that explanation, sorry.

As noted earlier, we?d still want crowbar OV protection regardless as the BMS would only protect the battery between 16-60v overvoltage event, not the other voltage sensitive things in the system.
 
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