Overcharged SLA battery

[Ridders897]

Hi all, hopefully someone can help.
I have a campervan with a SLA battery. Last night I plugged into the mains as the voltage was down to 12.2v. I left it plugged in overnight until my sterling b2b/ solar mppt started beeping at 0630 and the voltage meter read 16v. I unplugged the mains and the voltage dropped to 13.1v but i disconnected the terminals as there was a mild odour and I could hear a fizzing sound which is still audible with my ear upto the unit 2.5 hours later.
Any advice on weather the battery is still safe to use or not will be greatly appreciated as i am currently travelling and have a rapidly warming up fridge!

[smac999]

If it has water caps I would refill and try it. If it’s a sealed battery it may have lost a bunch of water with no way to refill it.

[StuM]

Do not use that battery. It has undergone thermal runaway. Here's a good reference to the subject:
https://www.cdtechno.com/pdf/ref/41_7944_0712.pdf

Note the conclusion:
Should severe thermal runaway occur, it will be evidenced by permanent container distortion due to the heat and eventual emission of trace amounts of hydrogen sulfide gas (rotten egg odor) as the electrolyte is completely gassed off. Should this situation be encountered, the charging voltage to the battery should be immediately removed to stop the thermal runaway reactions and the area should be ventilated. When thermal runaway has occurred, the damage to the battery is permanent and it must be replaced.

[StuM]

Originally Posted by smac999

If it has water caps I would refill and try it. If it’s a sealed battery it may have lost a bunch of water with no way to refill it.

The OP said SLA (= sealed lead acid)

[Malabarista]

Does it feel hot? I have 9 VRLA batteries and the fizzling sound is constant. None of them are hot and they are regularly checked for water (monthly) and with a hydrometer for specific gravity bi-monthly ( as it’s a pain). All are within specifications. I am not an expert so please feel free to ignore me.

[StuM]

Originally Posted by Malabarista

Does it feel hot? I have 9 VRLA batteries and the fizzling sound is constant. None of them are hot and they are regularly checked for water (monthly) and with a hydrometer for specific gravity bi-monthly ( as it’s a pain). All are within specifications. I am not an expert so please feel free to ignore me.

If your batteries are constantly fizzing, you have a problem regardless of construction.

Huh? How do you check a VRLA battery for water level and with a hydrometer?

https://microtexindia.com/what-is-a-vrla-battery/

[GordMay]

Greetings and welcome aboard the CF, Ridders.

Originally Posted by StuM

The OP said SLA (= sealed lead acid)

“SLA” usually stands for 'Sealed Lead Acid' battery, or Valve Regulated Lead Acid battery [VRLA].
However, I’ve occasionally heard SLA used to mean 'Starting, Lighting, Accessory' battery [as opposed to deep cycle, house type].

[StuM]

Originally Posted by GordMay

Greetings and welcome aboard the CF, Ridders.

“SLA” usually stands for 'Sealed Lead Acid' battery, or Valve Regulated Lead Acid battery [VRLA].
However, I’ve occasionally heard SLA used to mean 'Starting, Lighting, Accessory' battery [as opposed to deep cycle, house type].

First time I've ever heard that!
(Very few hits on google for that phrase either - only 14 results in total as opposed to 4,900,000 for "Sealed Lead Acid)


Something tells me it may be a backronym by people who don't know much about battery construction.

[GordMay]

Originally Posted by StuM

First time I've ever heard that!
(Very few hits on google for that phrase either - only 14 results in total as opposed to 4,900,000 for "Sealed Lead Acid)
Something tells me it may be a backronym by people who don't know much about battery construction.

I first heard that usage, from a technical representative [Siggy] of the Douglas Battery Manufacturing Co. [now defunct]. He lived in Winston-Salem, NC, and I took care of his sailboat, in Ft. Lauderdale [1990s].
I agree, as previously noted, that SLA usually stands for 'Sealed Lead Acid' battery, and was surprised at Siggy's usage.