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Marine battery issues

Discussion in 'Renewable Energy' started by Bach On, Apr 22, 2013.

  1. Bach On

    Bach On New Member

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    I was in a canoe that got swamped on a river. Both of my 12 volt lead acid batteries were completely underwater for almost two hours. They have vented caps. So fresh river water got into them. Afterwards, they wouldn't hold a charge very well. In desperation, I ended up pouring out the fluid and refilling them with fresh battery acid. (And Yes. I disposed of the old fluids in a responsible manner, thank you very much!)

    Now, they lose 10-20% of their power (according to my smart charger) in just a about five minutes of running a trolling motor. And we're not talking about some monster of a motor. These came from the local Walmart and were something like $100 each, with tax and exhange.

    I haven't put a hygrometer to each cell. Not real sure what the best approach is and just what I should be looking for.

    I've also read that the battery acid I got for a standard car battery may be a different formula from what is used in deep-cycle/marine batteries.

    Any sage advice from any experts here. This batteries were less than three months old. I hate to scrap them if they can be salvaged. But they don't seem reliable for their full 125 AH of reserve. I used them in parallel so I'd get 250 AH. I was trying to use no more than 20% of their reserve capacity before recharging.

    I also use these occasionally for running emergency lights.

    Any thoughts, ideas, hallucinations or wise suggestions will be appreciated.

    Bach On
     
  2. mvs sarma

    mvs sarma Well-Known Member

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    perhaps empty each cell by 40% of so called acid (could be 1.200 sp gravity dilution), add distilled water and charge the batteries at constant current , lower rate say 3amps until sp Gr reaches 1210 or so.

    this is with a thought that the plates are having sulphor in the form of lead sulphate, having partially discharged while last use before they fell into waters.

    Let you take 4 days no issue. i hope they would recover well
     
  3. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    Walmart and 3 months old: Aren't they still under warranty? I have exchanged failed batteries at Walmart. Walmart will test whatever you return to be sure it is failed. Your batteries are not quite failed yet, but it is an option worth considering for the future.

    1) Are you sure that exposure to river water caused the effects you now see? Yes, water could get in through a vented plug, but how much really got in? Moreover, you have flushed the cells. Did you use the smart charger to test capacity just before the incident? I would not assume they were any better before the incident than what you see now.

    2) As mvs sarma points out, the cells were partially discharged when they got flooded, so using full strength battery acid to flush may give too high a specific gravity when fully charged. Slow charging to a fully charged state, then flushing with acid of the correct specific gravity would address that concern.

    3) As I recall, the main difference between deep cycle batteries and starting batteries is in the plate construction, not the electrolyte. I would recommend using the electrolyte recommended by the manufacturer and/or dealer.

    John


    .
     
  4. dave

    Dave New Member

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  5. Bach On

    Bach On New Member

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    Thanks guys. This event happened over a year ago. So exchange at Walmart is no longer an option. And having them underwater for over an hour would probably be classified as abuse outside the terms of the warranty. They were working fine before this accident.

    I'll measure the specific gravity in each cell and see what - if anything - I can do. I also assumed the electrolyte was the same as a standard car battery. Otherwise, I wouldn't have tried this rather drastic step. I have a desulfanator that I've used on the things. It often helps breakup the coating that can get on the plates. It sometimes takes several weeks to accomplish any

    Bach On
     
  6. mvs sarma

    mvs sarma Well-Known Member

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    perhaps your trial is late by a life time of the battery itself.
    better forget., COOL
     
  7. RCinFLA

    RCinFLA Well-Known Member

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    Depends on state of charge when they got soaked.

    You must reestablish the plates to proper full charge before replacing electrolyte. Empty polluted electrolyte, replace with distilled water then place on charge at about 5% to 10% AH rating in current. This converts any sulfate on plates (partial discharge state) back into electrolyte acid. Then drain distilled water (actually weak acid) and replace with new electrolyte.

    As you did it you likely have too high specific gravity (too high acid concentration).
     
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