LiFePO4 chargers

On Tuesday, November 13, 2018 at 10:19:34 PM UTC-6, kinsell wrote:
On 11/11/18 7:02 AM, wrote:
On Saturday, November 10, 2018 at 12:03:42 AM UTC-6, kinsell wrote:
On 11/4/18 3:51 PM, wrote:
On Monday, November 5, 2018 at 8:02:04 AM UTC+10, wrote:
I also have heard the stories about fires while charging, but, as far as I know, most involved a different Lithium chemistry (Li-ion, Li-Polymer etc.) LiFePO4 is supposed to be safer, but by how much I do not know. At any rate, I am pretty much stuck with charging them in the plane, as they are mounted well behind the spar, and it takes a good 20-30 minutes to get them out and put them back in.

Here is an FAA report that supports the assertion that LiFePO4 cells are safer: https://www.fire.tc.faa.gov/pdf/TC-16-17.pdf

In their testing, which they admit had quite variable results, they did not get any thermal runaway with LiFePO4 cells, but did with all the other Li chemistries they tested. Note that the graphs in the above article show 1 cell out of 5 consumed by "thermal runaway" but that was the cell that they were heating externally to try and initiate the runaway.

Not to say that you shouldn't take precautions, all battery chemistries store enough energy to start an electrical fire, even if they are relatively immune to thermal runaway and overcharging.


I would hope they're safer than something like a li-po, model airplanes
using those things routinely put on a fireworks display during a crash..
Fascinating videos on YouTube.

However, "safer" isn't actually the same as "safe", LFP's are quite
capable of burning, despite what the scholarly articles say. There have
been a number of fires, particularly when they're used as starter
batteries. High charge rates and very high discharge rates seem to
cause problems, as homebuilders of small power planes have discovered.
There was also that LFP battery fire in an EB-28 in Finland this summer.

kinsell wrote on 11/13/2018 9:18 PM:
scinating videos on YouTube.

However, "safer" isn't actually the same as "safe", LFP's are quite
capable of burning, despite what the scholarly articles say.* There have
been a number of fires, particularly when they're used as starter
batteries.* High charge rates and very high discharge rates seem to
cause problems, as homebuilders of small power planes have discovered.
There was also that LFP battery fire in an EB-28 in Finland this summer.

-Dave

Dave, if you look around youtube long enough, you will find that a AAA battery
can make a fire. Certainly a 12V lead-acid has enough juice to do that if
circumstances are right. The overwhelming evidence of many years of usage of
LiFePo4 chemistry in glider batteries suggests that they are as safe as the old
gel-cells. Give progress a chance, I'm not saying be a Progressive.
Herb

If you come across a YouTube video of an AAA battery filling a cockpit with toxic
smoke, you be sure to post the link, OK?

Meanwhile, this is the sort of progress I can live without:

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

I did not see any indication the burning battery had a BMS. Some builders put in
the "starter" LiFe batteries that do not have a BMS, so perhaps that is the reason
the battery burned. I think LiFe batteries from the usual suppliers (Bienno, K2,
Stark - for example) with a BMS, used for instrument batteries, and charged with
the recommended charger are as safe as a comparable capacity SLA.


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

On Friday, November 16, 2018 at 7:20:53 PM UTC-8, Eric Greenwell wrote:
kinsell wrote on 11/13/2018 9:18 PM:
scinating videos on YouTube.

However, "safer" isn't actually the same as "safe", LFP's are quite
capable of burning, despite what the scholarly articles say.Â* There have
been a number of fires, particularly when they're used as starter
batteries.Â* High charge rates and very high discharge rates seem to
cause problems, as homebuilders of small power planes have discovered..
There was also that LFP battery fire in an EB-28 in Finland this summer.

-Dave

Dave, if you look around youtube long enough, you will find that a AAA battery
can make a fire. Certainly a 12V lead-acid has enough juice to do that if
circumstances are right. The overwhelming evidence of many years of usage of
LiFePo4 chemistry in glider batteries suggests that they are as safe as the old
gel-cells. Give progress a chance, I'm not saying be a Progressive.
Herb

If you come across a YouTube video of an AAA battery filling a cockpit with toxic
smoke, you be sure to post the link, OK?

Meanwhile, this is the sort of progress I can live without:

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

I did not see any indication the burning battery had a BMS. Some builders put in
the "starter" LiFe batteries that do not have a BMS, so perhaps that is the reason
the battery burned. I think LiFe batteries from the usual suppliers (Bienno, K2,
Stark - for example) with a BMS, used for instrument batteries, and charged with
the recommended charger are as safe as a comparable capacity SLA.


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

Several years ago I had a bad batch of batteries from one of the suppliers you mentioned in your post. 4 to 5 aH capacity in a 10 Ah battery. I quit selling them. I now sell LiFePO4 batteries that I personally test before shipping with a West Mountain Radio computer tester. Document is supplied with the battery.

http://www.craggyaero.com/lifepo4_battery.htm

Richard
www.craggyaero.com

Richard Pfiffner wrote on 11/17/2018 10:22 AM:
On Friday, November 16, 2018 at 7:20:53 PM UTC-8, Eric Greenwell wrote:

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



I did not see any indication the burning battery had a BMS. Some builders put in
the "starter" LiFe batteries that do not have a BMS, so perhaps that is the
reason the battery burned. I think LiFe batteries from the usual suppliers
(Bienno, K2, Stark - for example) with a BMS, used for instrument batteries,
and charged with the recommended charger are as safe as a comparable capacity
SLA.



Several years ago I had a bad batch of batteries from one of the suppliers you
mentioned in your post. 4 to 5 aH capacity in a 10 Ah battery. I quit
selling them. I now sell LiFePO4 batteries that I personally test before
shipping with a West Mountain Radio computer tester. Document is supplied with
the battery.

http://www.craggyaero.com/lifepo4_battery.htm

I test every battery before installing it, also using a West Mountain tester. Over
the years, I've had three SLA batteries that had half their rated capacity, and
returned them. I've only used one LiFe battery, and it had exactly the rated
capacity. Couldn't believe it - tested it again, and got the same answer.