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Re: [EVDL] Sugarcoating and cell photography (WAS: Floodies/Batt.murder mystery)

Hi Lee,

Lee Hart writes:
> The cloudiness you get in the electrolyte is from microscopic bits of
> this lead sulfate that fell off the plate due to vibration or heavy
> gassing. It usually settles out at the bottom as "sludge". If it gets
> deep enough, it can short the plates together at the bottom. At that
> point the battery is basically shot.

I was wondering whether this always results in a benign failure (ie. dead battery), or if it can also lead to more catastrophic failures?

Cheers,
Claudio

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Discussion Starter #2
Re: [EVDL] Sugarcoating and cell photography (WAS: Floodies/Batt.murder mystery)

>> The cloudiness you get in the electrolyte is from microscopic bits
>> of this lead sulfate that fell off the plate due to vibration or
>> heavy gassing. It usually settles out at the bottom as "sludge".
>> If it gets deep enough, it can short the plates together at the
>> bottom. At that point the battery is basically shot.

From: Claudio Natoli
> I was wondering whether this always results in a benign failure
> (ie. dead battery), or if it can also lead to more catastrophic
> failures?

The sludge will typically build up slowly, and so slowly short out the cell. Externally, you have a battery that self-discharges itself in a short time.

It's possible for some catastrophic event to cause a lot of material to be shed all at once. It could be a very deep discharge or drastic overcharge, or extreme vibration, or flipping a flooded battery on its side, etc. If the sludge causes too good a short, it can cause the cell to get hot, and even boil the electrolyte or melt the plates. Depending on the circumstances (is it on charge at the time? Are there other batteries in parallel?) things can get really bad fast!

--
"Excellence does not require perfection." -- Henry James
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net

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