SLA batteries opinions?

You are confusing Lipo with with li ion, the modellers problems were with lithium polymer batteries, not the type we are discussing.

On Thursday, April 5, 2018 at 10:20:48 AM UTC-7, Richard Pfiffner wrote:
On Thursday, April 5, 2018 at 8:04:40 AM UTC-7, Tango Eight wrote:
On Thursday, April 5, 2018 at 10:52:17 AM UTC-4, Richard Pfiffner wrote:
On Wednesday, April 4, 2018 at 10:16:45 PM UTC-7, kinsell wrote:
On 04/04/2018 04:04 PM, Richard Pfiffner wrote:
On Wednesday, April 4, 2018 at 2:31:07 PM UTC-7, kinsell wrote:
Wow. Didn't these batteries have a battery management system to prevent
damage?



On 04/04/2018 03:22 PM, Richard Pfiffner wrote:



John,

My experiences with LiFePO4

I have never heard of a LiFePO4 battery catching fire. I have had some customers connect reverse polarity. It burnt up the internal positive wire but the battery did not burn. I also just shorted a LiFePO4 12V10Ah turned it upside down and placed on a metal plate. It got hot and distorted the case near the contacts for the cells. It did not burn and was cool when I looked at it 1/2 hour later.

I had one supplier that gave me 24 Volt chargers by mistake. I charged one battery overnight and it got very large but did not catch fire..

Richard
www.craggyaero.com


I have found that BMS will not save a short.

Richard
www.craggyaero.com


A good short should bring the terminal voltage below 10 volts instantly,
strange the BMS didn't kick in before damage occured.

Also a bood BMS ought to prevent overcharging , which clearly didn't
happen with the 24 volt chargers. If I had a battery swell in my
ASH-26E, it would cause some significant damage.

The overcharging was a Stark Battery.

I will try the short on the famously expensive K2 battery today.

Standby for results.

Richard
www.craggyaero.com

Need video :-).

T8

Video shows nothing battery gets hot and cuts out at I suspect about 10V.

Richard
www.craggyaero.com

Richard, try dropping a similar sized SLA on a metal plate.

On Thursday, April 5, 2018 at 8:14:21 PM UTC-7, jfitch wrote:
On Thursday, April 5, 2018 at 10:20:48 AM UTC-7, Richard Pfiffner wrote:
On Thursday, April 5, 2018 at 8:04:40 AM UTC-7, Tango Eight wrote:
On Thursday, April 5, 2018 at 10:52:17 AM UTC-4, Richard Pfiffner wrote:
On Wednesday, April 4, 2018 at 10:16:45 PM UTC-7, kinsell wrote:
On 04/04/2018 04:04 PM, Richard Pfiffner wrote:
On Wednesday, April 4, 2018 at 2:31:07 PM UTC-7, kinsell wrote:
Wow. Didn't these batteries have a battery management system to prevent
damage?



On 04/04/2018 03:22 PM, Richard Pfiffner wrote:



John,

My experiences with LiFePO4

I have never heard of a LiFePO4 battery catching fire. I have had some customers connect reverse polarity. It burnt up the internal positive wire but the battery did not burn. I also just shorted a LiFePO4 12V10Ah turned it upside down and placed on a metal plate. It got hot and distorted the case near the contacts for the cells. It did not burn and was cool when I looked at it 1/2 hour later.

I had one supplier that gave me 24 Volt chargers by mistake. I charged one battery overnight and it got very large but did not catch fire.

Richard
www.craggyaero.com


I have found that BMS will not save a short.

Richard
www.craggyaero.com


A good short should bring the terminal voltage below 10 volts instantly,
strange the BMS didn't kick in before damage occured.

Also a bood BMS ought to prevent overcharging , which clearly didn't
happen with the 24 volt chargers. If I had a battery swell in my
ASH-26E, it would cause some significant damage.

The overcharging was a Stark Battery.

I will try the short on the famously expensive K2 battery today.

Standby for results.

Richard
www.craggyaero.com

Need video :-).

T8

Video shows nothing battery gets hot and cuts out at I suspect about 10V.

Richard
www.craggyaero.com

Richard, try dropping a similar sized SLA on a metal plate.

I suspect a fire or at least a lot hotter.

Richard.