Author Topic: Sealed Lead Acid Battery Short  (Read 723 times)

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Offline minibutmany

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Sealed Lead Acid Battery Short
« on: March 25, 2013, 09:57:04 AM »
Today we had a bit of a scare with a sealed lead acid battery as the leads being used to connect it to the circuit we were testing shorted out. There was a ton of smoke but we were able to disconnect it fairly quickly before anything insane happened. The leads are now completely melted through. My question was on if this battery is at all usable now. I tested it and it is surprisingly still at nominal voltage. The seal seems to be broken so I thought it might not be safe to run indoors.
Thanks,
Kelly

Offline houdini

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Re: Sealed Lead Acid Battery Short
« Reply #1 on: March 25, 2013, 12:09:31 PM »
yes it most likely fine.

Offline A Hellene

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Re: Sealed Lead Acid Battery Short
« Reply #2 on: March 25, 2013, 01:34:10 PM »
If the battery vent seals are broken, this is a result of pressurised gas («??????? ?????»* in Greek, i.e. oxygen and hydrogen in perfect burning analogies, which explodes violently when ignited) escaping the battery compartments. This usually happens during overcharging, and the vent valves protect against explosion from the gaseous pressure being built within the sealed battery compartment.

In your case, I think that the extended short circuit overheated the plates, resulting in the vaporisation of some of the electrolyte and the permanent destruction of a part the battery plates coating material.

Anyway, if the electrolyte has lost water (in the form of escaped gasses) the battery needs to be replaced because the electrolyte acid concentration is not right anymore, directly affecting the battery capacity and life.


-George


[ * ] Transliterated: "crotoun aerio" (since the forum software database does not seem to support Greek characters...)
« Last Edit: March 25, 2013, 01:37:00 PM by A Hellene »

Offline G7PSK

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Re: Sealed Lead Acid Battery Short
« Reply #3 on: March 25, 2013, 11:35:18 PM »
What size was battery and what size were the leads as it is more than likely that with a large battery and not to big leads that the battery did not even grunt in order to burn the leads out.

vlf3

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Re: Sealed Lead Acid Battery Short
« Reply #4 on: March 26, 2013, 12:34:08 AM »
The vent seal has poped due the short terminals, however brief the short, gasing has occured...  :o
if the the battery takes a re-charge ! and not showing a high current reading at the start, then it has survived
the short.  However, if the charge current starts high and shows no sign of reducing within 10 minuits of charging,
then the damage has been done, and the plates are damaged... that being the case, replace the battery.

Offline knarf.be

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Re: Re: Sealed Lead Acid Battery Short
« Reply #5 on: March 27, 2013, 11:52:11 PM »
The vent seal has poped due the short terminals, however brief the short, gasing has occured...  :o
if the the battery takes a re-charge ! and not showing a high current reading at the start, then it has survived
the short.  However, if the charge current starts high and shows no sign of reducing within 10 minuits of charging,
then the damage has been done, and the plates are damaged... that being the case, replace the battery.
Thats true, I once tried to charge an old lead-acid battery but it was just drawing current, and not charging.

Maybe it's a good idea to just solder a fuse between the wires, to prevent it from happening again.



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