Lithium-ion batteries important safety message

[airtractor8]

https://www.atsb.gov.au/publications...n/ab-2018-124/

[rv8ch]

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.

[rmartingt]

Originally Posted by rv8ch

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.

[jliltd]

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".

[jcaplins]

Originally Posted by jliltd

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.

[isosceles]

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.

[ppilotmike]

Originally Posted by isosceles

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...?

[Finley Atherton]

May have been one of the older Deltran batteries that did not have any built-in protection?

Fin
9A

[Malndi]

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.

[sibriggs]

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