Author Topic: 12v battery @5 volts  (Read 4684 times)

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electrondady1

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12v battery @5 volts
« on: April 04, 2010, 12:27:19 PM »
i brought some seldom used marine batteries into the house last fall so they would not discharge in there vehicles and freeze  over the winter.

(i hate when that happens)

i trickle charged them up to proper voltage and then left them on a wooden floor.

i just went to check them.

two are fine but one had an oily looking residue on the top and reads 5 volts

i carefully washed the top with a baking soda solution to neutralize this residue and pulled the caps of the cells.

the solution level is even in all cells, not down very much if at all.

it's back on the charger.

when a marine type battery discharges this much can it be brought back ?
« Last Edit: April 04, 2010, 12:27:19 PM by (unknown) »

bob g

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Re: 12v battery @5 volts
« Reply #1 on: April 05, 2010, 12:32:51 AM »
can it be brought back?


i am betting no...


in my experience flooded cells are very unforgiving when it come to sitting in a discharged state, even a day or two seems to kick their butts real hard.


i feel your pain


bob g

« Last Edit: April 05, 2010, 12:32:51 AM by bob g »
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Flux

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Re: 12v battery @5 volts
« Reply #2 on: April 05, 2010, 01:09:10 AM »
I agree. I can't help feeling that that battery had some serious problems before you put it into storage.


Sealed lead acid do in fact store better than flooded ones, but a decent working flooded cell should still survive many months if fully charged before leaving. If it is in a poor state with high self discharge then it may expire unless more or less constantly being charged, it was probably near the end of it's life.


Much depends on what has happened, if all cells are flat then it will be badly sulphated and probably won't recover. More likely I suspect one cell is faulty and near open circuit but unless you have external link bars you can't work out where it is wrong.


If one cell is duff it may respond to charging and come back to limited life but it will never be something to rely on.


Flux

« Last Edit: April 05, 2010, 01:09:10 AM by Flux »

electrondady1

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Re: 12v battery @5 volts
« Reply #3 on: April 05, 2010, 09:04:21 AM »
thanks so much for your replies

after 24 hrs on a one amp charger the battery reads 15 volts.

i beleave thats what you call a surface charge.

so to find the real health  of this battery i will monitor the discharge rate.

« Last Edit: April 05, 2010, 09:04:21 AM by electrondady1 »

ghurd

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Re: 12v battery @5 volts
« Reply #4 on: April 05, 2010, 09:28:14 AM »
It sounds like it is toast to me.

Try connecting a 1 or 2.2A bulb (ie #1156 tail light bulb) while reading the voltage.

I have a feeling the voltage will fall like a rock.

G-

« Last Edit: April 05, 2010, 09:28:14 AM by ghurd »
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bob g

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Re: 12v battery @5 volts
« Reply #5 on: April 05, 2010, 10:20:51 AM »
you might have to keep it at 15 or 16 volts for several days, at very low amperage

and it might come back some...


probably not worth it for a battery of questionable history and value.


bob g

« Last Edit: April 05, 2010, 10:20:51 AM by bob g »
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electrondady1

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Re: 12v battery @5 volts
« Reply #6 on: April 05, 2010, 02:42:15 PM »
chapter two

after sitting about 7 hrs the battery is down to 13.5 volts.

i'll put it back on life support for another night and try Gurds test in the morning.
« Last Edit: April 05, 2010, 02:42:15 PM by electrondady1 »

Rover

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Re: 12v battery @5 volts
« Reply #7 on: April 05, 2010, 02:56:13 PM »
I'm kinda curious, from your post you said there was an oily residure on top, that you then neutralized (I assume thinking it was batter electrolyte)


how do you think it got there?

« Last Edit: April 05, 2010, 02:56:13 PM by Rover »
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Norm

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Re: 12v battery @5 volts
« Reply #8 on: April 06, 2010, 04:54:59 AM »
I agree with the others....they are more or less

telling you to forget it and move on....it's not

part of a battery bank so the vehicle that it

came from will be the better off by springing for

a new battery.....only one other thing you might

consider.....maybe it was the vehicle that caused

it to go bad?

 
« Last Edit: April 06, 2010, 04:54:59 AM by Norm »

hydrosun

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Re: 12v battery @5 volts
« Reply #9 on: April 06, 2010, 01:30:25 PM »
When I check batteries at the recycle center for candidates for use I reject anything that is less than 10 volts. Unless a cell is shorted it should be above that. I've also put the tip of a voltmeter probe into the battery acid and checked individual cells that way. If the difference between two cells is close to zero it's toast.

Chris
« Last Edit: April 06, 2010, 01:30:25 PM by hydrosun »

ghurd

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Re: 12v battery @5 volts
« Reply #10 on: April 06, 2010, 02:28:10 PM »
If it quickly runs down to about 10.5 or 8.4V, or less, then it is toast.

G-

« Last Edit: April 06, 2010, 02:28:10 PM by ghurd »
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Ungrounded Lightning Rod

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Re: 12v battery @5 volts
« Reply #11 on: April 06, 2010, 04:31:48 PM »
The classic way to do that is to clamp onto two lead rods to stick into the electrolyte.  They model the negative electrode of a fully-charged cell.  You do pairs of holes and at the negative end put one in a hole and probe the post with the other.
« Last Edit: April 06, 2010, 04:31:48 PM by Ungrounded Lightning Rod »

Ungrounded Lightning Rod

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Re: 12v battery @5 volts
« Reply #12 on: April 06, 2010, 04:32:29 PM »
Make that "at the positive end".
« Last Edit: April 06, 2010, 04:32:29 PM by Ungrounded Lightning Rod »

XeonPony

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Re: 12v battery @5 volts
« Reply #13 on: April 29, 2010, 12:14:53 PM »
5V indicates shorted cell, you can drive the volts up and it will "pretend" to be good but being in a group of robotic engineers we can all assure you it is toast and not to waste time, 8v or so I'd say give it a shot, but at 5v it is terminaly dead!

Late comming into the thread I know but for futur persons referance any thing under 8v move along and get a new bat.
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