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Registered Member #3883
Joined: Fri May 13 2011, 06:30PM
Location: Norway
Posts: 87
Steve Conner wrote ... you're not supposed to add acid to a battery.
Actually you can. If the acid concentration after charging is too low it is possible to readjust it, but lost acid indicates a serious problem with the cells. So chances are that anything other than a minor adjustment will be a waste of time and acid.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Try to put the battery through a few charge/discharge cycles, the capacity may increase. Charge to 15 volts current limited to 0.7A, after reaching 15V wait for the current to fall to some 0.1A then disconnect the battery. If the bat doesn't draw any current at 15V, let it sit there for a while, the same applies for discharging, even when there's 0V on it when loaded, let the load connected for some minutes.
These sealed batteries are specially designed so they don't gas at 15V and you're not supposed to add any electrolyte. From what I've heard, this usually doesn't help and may kill a half-good battery.
Registered Member #607
Joined: Tue Mar 27 2007, 10:39AM
Location:
Posts: 64
Also be aware that a lot of SLA batteries no longer use a liquid, but a jelly or paste. It allows them to be used "any way up." Unsealing and adding a liquid electrolyte may be messy and explosive. Cheers.
Registered Member #3943
Joined: Sun Jun 12 2011, 05:24PM
Location: The Shire, UK
Posts: 552
Mark-H wrote ...
Also be aware that a lot of SLA batteries no longer use a liquid, but a jelly or paste. It allows them to be used "any way up." Unsealing and adding a liquid electrolyte may be messy and explosive. Cheers.
Are you talking about the AGM types? arn't they usually more expensive than standard sealed lead acid types?
Registered Member #607
Joined: Tue Mar 27 2007, 10:39AM
Location:
Posts: 64
Most likely... I use them on motorcycles where they have to be put in awkward places. The price depends on the "manufacturer." Read: Whoever puts their name on it. Cheers.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
SLAs are designed to have a specific quantity of electrolyte, with negligible water content. So-called "starved electrolyte". if you add anything to these, they break, permanently.
About the only fix I've found is to leave a solar panel connected for a week or so, with voltage limited to 15V max. Normally this works, but if the unloaded voltage is less than 10V then it is likely not to recover.
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Restoring a sealed 12v 7ah rechargeable battery?
