On Saturday, March 23, 2019 at 7:42:49 AM UTC-7, kinsell wrote:
On 3/22/19 11:23 PM, 2G wrote:
On Friday, March 22, 2019 at 9:23:17 PM UTC-7, kinsell wrote:
On 3/22/19 8:23 PM, 2G wrote:
On Tuesday, March 19, 2019 at 10:04:00 PM UTC-7, kinsell wrote:
On 3/17/19 9:54 PM, Eric Greenwell wrote:
kinsell wrote on 3/16/2019 9:46 PM:


Many of us are flying with multi-cell LiFePO4 batteries that have
internal wiring and are not filled with resin.Â* Is that a problem?
Or is the location of the batteries in this specific glider such that
the resin is advisable?Â* A battery fire anywhere in a glider (even
without a fuel tank) is catastrophic. OTOH I havn't heard of any
fires with this type of battery.Â* It's the lithium-polymer battery
pack (also much larger, with many more cells) in the FES systems that
has had fires.


Well, the service bulletin talks about an LFP that burned.Â* There was
a fire in an EB-28 in Finland last year with a 10 A-H LFP.Â* Here's a
video of an LFP burning:

https://www.pilotsofamerica.com/comm...-fires.102016/


There have been claims that LFP's don't burn, but that's simply not true.

The Aerovoltz battery that burned did not have a BMS; in fact, none of
the Aerovoltz batteries have a BMS (battery management system). I would
not want to use one, even though the short engine runs typical of
self-launchers means problems would be less likely than in airplanes.
The Earth-X batteries all have a BMS, seem better characterized, and I
would trust them a lot more.


Yes, EarthX is well regarded in the homebuilt powerplane world. Dual
redundant BMS boards to make you feel good. Here's a greatpicture of one:

http://www.avidfoxflyers.com/index.p...ttery-warning/

If you poke around, there's a nice video from the Director of
Engineering at EarthX, he talks about the requirement to have a
gas-tight battery box vented to the outside, to use only a three-phase
alternator to charge it, and to add a crowbar circuit to prevent
over-voltage. Wonder how many glider pilots go to all this trouble?

I think I'll stick to SLA, just press the button and the engine starts
in about a second.


-Dave

P.S. That StewartB in the original thread was a real hoot. Said he
worried more about getting mad cow disease than having trouble with his
EarthX battery. Until his battery went bad. Don't know if he still
eats hamburgers or not.

Dave,

Perhaps you could post a link to this video - I could not find it. To the contrary, the video I could find extolled the safety of their batteries in aircraft:
https://earthxbatteries.com/product-...ental-aircraft


That video was in an EAA seminar:

http://go.eaa.org/UVqR00U0BE0SOs03oK000hV


Some good info on charging systems he

https://earthxbatteries.com/engine-c...hium-batteries

I am confused, is EarthX saying you have to enclose your lithium battery in a sealed box or not? If so, then why don't they say so on their website?


Websites are intended to sell product. You put too much truth on them,
they become less effective. It's like the Aerovoltz guy admitting that
the products are "smokebombs", you're not going to find that on the website.

Dave,

Did you actually watch this video? I ask because your link was a registration by someone else to the webinar, and doesn't work even if you put in your own email. I did find the webinar he
https://video.eaa.org/detail/video/5...%20E xplained
I watched the whole thing and didn't find reference to a gas-tight box with venting. He did say that EarthX has done a lot of testing of their lithium batteries and haven't seen one go into thermal runaway. He also said that thermal runaway occurs at temperatures starting at 270 C, the highest of all lithium chemistry's.

You wrote:
"Dual
redundant BMS boards to make you feel good. Here's a greatpicture of one:

http://www.avidfoxflyers.com/index.p...ttery-warning/ "

If you had gone to the next page, you would have learned that the battery pictured is an ETX12A, which DOES NOT have a BMS. Furthermore, it was used on an engine w/o a starter, contrary to the direct warnings by EarthX:
http://www.avidfoxflyers.com/index.p...arning/&page=2
In other words, this incident has absolutely nothing to do with our application.

Finally, you say I put "too much truth" on company websites. I have said this befo I DO NOT vouch for the accuracy of any company's literature or video, whether it is printed or online; I merely make reference to it so you can make your own decision. But, if you do not believe what they are presenting, DO NOT USE THEIR PRODUCTS!