12v 17aH SLA battery is at 9v - is it dead?

MikeHunt79

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Nov 28, 2005
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Bristol, UK
My only car charger is an automatic one, and when it is connected, it keeps turning itself on and off... you can hear the relay clicking...

Is this battery dead, or is there a way or reviving it?

It's from a UPS... I left is unplugged for too long. :(
 

Illum

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a 12V battery, if drained below 10V, its pretty much totaled, I know 'cause I've destroyed a few...including one I drained to about 7V...[cooling fan proto set in the shed, 200ma current draw, but forgot about it]:ohgeez:
 

Fallingwater

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I drained my scooter's battery to 5v by letting it stay unused for more than a year.
A few days with a desulfator and charger connected in parallel, and it's now as good as new.

I don't know if a desulfator will run right on SLA cells, though, but it's cheap to try.
 

BatteryCharger

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a 12V battery, if drained below 10V, its pretty much totaled
Not really. They shouldn't be drained that far, but it won't kill one, unless it's already on it's way out.

I have a 19ah SLA that came out of a portable jump starter. I've had it around 8 years I think. I used to think you had to drain it all the way before you charge it, so I turned on it's built in light and drained it until the light went out. I often left it that way for months at a time before charging it. I did this many, many times.

That poor abused battery still lasted about 7 years of constant abuse before it's capacity dropped to 3ah. Recently I left it connected to a "Battery Minder" desulphating charger for about two weeks. It now holds 14ah, and will jump start my huge old 454 V8 engine. I HIGHLY recommend the Battery Minder, it pays for itself, and makes an all around good automatic charger.
 

TorchBoy

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I HIGHLY recommend the Battery Minder, it pays for itself, and makes an all around good automatic charger.
Some years from now I'll probably say to myself "Now, what was that think for fixing SLAs?" and not be able to find this thread. Do you have a link handy?
 

Fallingwater

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5V? wow....
Yes, I too was impressed. It's quite possible that it's not completely restored; I haven't measured amps carefully, and the battery is not marked with its original capacity so I wouldn't know anyway.
It has more than enough juice to start the engine without the starter motor slowing down after a few seconds of activity, though (yes, I need to clean the carburetor), so I'm not worried.

desulphating
[grammar_nazi]It's actually spelled "desulfating", as the phenomenon it fights is called "sulfation".[/grammar_nazi]
 

Illum

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I was told of not draining below 10V as a general rule of battery use and maintainence....I guess I should've kept a few of those SLA/gel cells I thought I had totalled:shakehead
 

BatteryCharger

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TorchBoy

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Fallingwater, since your location isn't in the United States I'm surprised at your insistence on the American spelling of sulfur. The British spelling of sulphur is quite accepted - even normal - in many other parts of the world, and it would be wrong to say either is wrong, especially in an international setting like this forum. Having said all that, while sulphur is the normal spelling in this country, I personally prefer to use sulfur because the International Union of Pure and Applied Chemistry and the Royal Society of Chemistry both use that version. (I note they also use aluminium.)

:grouphug:
 

Thujone

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I guess these rules dont apply to all sla batts, many times i have left the key on in my motorcycle droping the batter as low as 4v once and 6v another time, on times it is too low for my battery tender to recover it I just hook up my titan. Still working just fine for me, and it has only lost about 1ah capacity.
 

Fallingwater

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Fallingwater, since your location isn't in the United States I'm surprised at your insistence on the American spelling of sulfur. The British spelling of sulphur is quite accepted - even normal - in many other parts of the world, and it would be wrong to say either is wrong, especially in an international setting like this forum. Having said all that, while sulphur is the normal spelling in this country, I personally prefer to use sulfur because the International Union of Pure and Applied Chemistry and the Royal Society of Chemistry both use that version. (I note they also use aluminium.)
I'm not completely serious, in case it wasn't clear. :p

Oh, yeah, wikipedia is always right.
You have a point.
However, you can't beat Google Fight for accuracy :p
 

KevinL

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I'm not completely serious, in case it wasn't clear. :p


You have a point.
However, you can't beat Google Fight for accuracy :p

ROTFL!!!!!!!!

That is brilliant!!

On a slightly-more-serious note (not that we ever are :nana:), remember it's just words. And words are a frail, fallible tool. We only use them because they're the best we have.. as long as everybody 'gets' what each other means, it's all good :)

I personally tend to use US English (because teh speel chekr werks tht waay ;) and I'm too lazy to change it to UK English) but I read and accept both spellings. But that's just me. :D
 
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