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Forum Index : Electronics : Batteries

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readyakira

Senior Member

Joined: 17/07/2008
Location: United States
Posts: 114
Posted: 02:01pm 18 May 2010
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I have a few deep cycle batteries that were given to me. They have been sitting a long time and have a sitting voltage of about 8.2v How do I go about checking these to make sure cells arent shorted and maybe bringing these to life? I am guessing I need to use a gravity meter? and desulphator then maybe b e able to try a charge?
Don't you think Free/Renewable energy should be mandatory in new buildings?
 
Tinker

Guru

Joined: 07/11/2007
Location: Australia
Posts: 1904
Posted: 03:13pm 18 May 2010
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The first thing I would do is connect them to a charger and see what happens. If they do not accept a charge in a reasonable time I see little reason to pursue other than a trip to the battery recycle place.
Klaus
 
Downwind

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Joined: 09/09/2009
Location: Australia
Posts: 2333
Posted: 04:13pm 18 May 2010
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As Klaus said, charge them first as you have the procedure backwards.

At this point a gravity meter will only tell you they are flat and at 8.2 volts i can tell you they are flat from the other side of the world.

Give them a go on the charger as you have little to loose.

Pete.
Sometimes it just works
 
Bub73

Senior Member

Joined: 10/12/2009
Location: United States
Posts: 116
Posted: 09:55pm 18 May 2010
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Deep cycle batteries like to be charged slowly; if they respond at all then consider pulse charging and/or a desulphator .
It takes a lot of time to bring a battery back the flatter they are the less the chance to recover them.
As Pete said above give them a try on the charger; I always do.......

Bob
 
VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 03:08am 19 May 2010
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Hi Ready

I have brought batteries back from the dead with a desulphator and a trickle charge as long as there is no mechanical faults or shorted cells. trickle charge for a week and if the voltage is still the same or below 12 volts may be no good, if the off charge voltage stays around 12 volts then desulphate for a couple of weeks, after that the voltage should be around 13.2 volts off charge if they are any good. If you can get them to 13.2 volts or above it is worth leaving the desulphator on them for a few weeks as it takes time for them to regain capacity.

All the best

Bob

PS" If they are heavily sulphated the specific gravity measured by the hydrometer isn't much of an indication as it will read low because a lot of the acid is in sulphate form.Edited by VK4AYQ 2010-05-20
Foolin Around
 
readyakira

Senior Member

Joined: 17/07/2008
Location: United States
Posts: 114
Posted: 12:21pm 19 May 2010
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well, after leaving it on a 1amp solar charge for 24hrs the low voltage light is on on the charger. I didn't have any of my DMM's to check the actual resting voltage but I will check that after work today. These were used in an RV and from my understanding something kept tripping a breaker so the guy thought it was the battery. He said the genny would come on for no appearent reason sometimes when he wasn't using any power. I suspect these to be bad, but hate to throw anything away if possible to salvage it.
Don't you think Free/Renewable energy should be mandatory in new buildings?
 
VK4AYQ
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Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 03:21pm 19 May 2010
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Hi Ready

It is worth a try, because there could have been a fault somewhere in the system causing them to discharge. I would suggest you use a charger with a few more amps initially as a 1 amp charge is dissipated very easily in a flat battery. On the power plant batteries 32 volt and 48 volt I used 100amp charge for a few minuets to get initial conductivity going in badly sulphated batteries, a good rule of thumb is 20% of the rated amp hr of the battery, not enough to do damage but enough to get the process going.

All the best

Bob
Foolin Around
 
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