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scott_fury View Drop Down
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    Posted: 08 July 2014 at 5:41pm
I left my box on accidentally and didn't realise for a couple of weeks. Now the 18ah SLA battery won't hold charge about 11.5V.

I have a charger that has a desulphator, which it uses when the battery charge is under 25%. It also has a top up feature for when the battery is on charge for extended periods.

I have read that one way to get a battery back to life is to attach a 20w light bulb to it and have the battery charger connected and on a timer so that you charge it up and run it down repeatedly for 24/48 hours and this helps to extend the life.

Does anyone have any advice or experience with this? Would be great to know if there's a chance of saving it, before I have to fork out for a new one. Cheers.

Edited by scott_fury - 08 July 2014 at 5:46pm
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Zed's dead, baby. Zed's dead.
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Shit negro, that's all you had to say
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Points: 2713 		Post Options Post Options   Thanks (0) Thanks(0)   Quote slaz Quote  Post ReplyReply Direct Link To This Post Posted: 08 July 2014 at 7:38pm
Originally posted by scott_fury scott_fury wrote:

I left my box on accidentally and didn't realise for a couple of weeks. Now the 18ah SLA battery won't hold charge about 11.5V.

I have a charger that has a desulphator, which it uses when the battery charge is under 25%. It also has a top up feature for when the battery is on charge for extended periods.

I have read that one way to get a battery back to life is to attach a 20w light bulb to it and have the battery charger connected and on a timer so that you charge it up and run it down repeatedly for 24/48 hours and this helps to extend the life.

Does anyone have any advice or experience with this? Would be great to know if there's a chance of saving it, before I have to fork out for a new one. Cheers.


..... dead Jim. Doorstop.
REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON
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Yep.
 
We use a lot of SLAs on portable floodlighting. If it will only hold 11.5 VDC off load then its dipped beyond the point of no return. We have "revived" a few over the years only for them to last 20 or 30 minutes and then die when back in the field.
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Points: 740 		Post Options Post Options   Thanks (0) Thanks(0)   Quote amlu Quote  Post ReplyReply Direct Link To This Post Posted: 09 July 2014 at 4:07pm
theres tricks involving zapping them up with a welder or something. or desulphating and so on. i got collection on more of less dead sla from alarms, one day when got bit of time will play with them and see, nothing to loose anyway
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scott_fury View Drop Down
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I need to get a power supply sorted by next weekend, so I'll have to get new one, but will still have a go with the method I listed above. I was reliably informed it would do something. If, by some slight miracle, it works I will post my results

Edited by scott_fury - 09 July 2014 at 5:02pm
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I've been told about forcing a massive current as a method of recovering normal lead-acids, and then topping off the acid as it can evaporate as a result.

Not sure how this would work for an SLA though, probably worth not being too close when putting large amounts of current through a sealed box...
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Points: 2295 		Post Options Post Options   Thanks (0) Thanks(0)   Quote bitSmasher Quote  Post ReplyReply Direct Link To This Post Posted: 09 July 2014 at 11:16pm
Originally posted by amlu amlu wrote:

theres tricks involving zapping them up with a welder or something
Originally posted by Blaize110 Blaize110 wrote:

probably worth not being too close when putting large amounts of current through a sealed box...
Sounds like something that'd be worth video'ing for YouTube Wink
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You will want to get a new battery. 
However, I wouldn't give up on the old one completely - try one of the many desulphation tricks, all of which are aimed at electro-mechanically breaking off the layer of solid lead sulphate that now covers your plates. You may be able to recover a useful amount of capacity.  I have seen a lot of Youtube videos of various rednecks having some measure of success with dead lead-acid batteries. It'll never be 100% again though. It might just boil itself to complete death.
I think in general desulphation works best on large flooded cells where you have the option of also draining and replacing the acid, which will be full of particles of sulphate after you've got it to fall off the plates. Then your plates are a bit thinner, and you've still lost some capacity, or at least cranking current. Considering SLA or gel cells, I am not sure where the detached sulphate would go - it's all semi-solid in there....
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Points: 517 		Post Options Post Options   Thanks (0) Thanks(0)   Quote lutkeveld Quote  Post ReplyReply Direct Link To This Post Posted: 10 July 2014 at 3:04pm
Why bother? Maybe you'll get 10% capacity back, but you still have to carry all the weight with you. 
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Points: 319 		Post Options Post Options   Thanks (0) Thanks(0)   Quote scott_fury Quote  Post ReplyReply Direct Link To This Post Posted: 10 July 2014 at 3:06pm
I've already bitten the bullet and I'm right now sat in my house waiting for UKMail to apparently deliver it by 2:15pm :(. I'll still try it out as it's always good to have a spare battery to test things on. I'm also a big believer in the power of YouTube as a tool for learning (and listening to rare vinyl), having rescued knackered belongings from laptops to 3-speed bicycle hubs. Not holding out on batteries though!
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