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Old June 2nd 20, 03:40 PM posted to rec.aviation.soaring
2G
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Default K2 battery endurance

On Monday, June 1, 2020 at 9:46:09 PM UTC-7, kinsell wrote:
On 5/25/20 9:47 PM, Eric Greenwell wrote:
2G wrote on 5/25/2020 2:20 PM:
On Wednesday, May 13, 2020 at 8:00:09 PM UTC-7, kinsell wrote:

...

The BMS in all LFPs may not have the same functionality regarding
balancing but at the very least they should start/stop accepting
charge appropriately.


It matters not what you think should happen, the truth is not all LFP
batteries have a BMS, and of those that do, not all of them protect from
over and under voltage.

Which LFP batteries don't have a BMS?

Tom


The "powersports" (ie, for engine starting) LFP don't always have a BMS.
A motorglider pilot might be tempted to use one for the engine, for
example.


StarkPower had a series of batteries aimed at motorcycles that they were
quite open about not having a BMS. Unfortunately they're in Chapter 7
now and the website is gone.

More commonly, some batteries with BMS don't have over and under voltage
protection. Richard Pfiffner one time was testing batteries, and his
vendor shipped 24 volt chargers accidentally for 12 volt batteries. All
the white stuff leaked out of the battery. Some electrical genius on
R.A.S. (don't remember which one) declared that they really had
overvoltage protection, but 24 volts just wasn't enough to trigger it.

One of our fellow Schleicher motorglider pilots had an LFP, left the
transponder on, and ruined the battery. A 15-20 AH battery intended as
a starter battery can easily find it's way into other applications. You
may have read about the ASG 32 mi that got fried when the solar
controller malfunctioned, drained the battery, and got quite hot when
charged from another charger. Did it have a BMS? Doesn't really matter.

Dave


I think it matters: what kind of battery was it?

Tom