Thread: 7Ah sealed lead acid current draw

  1. #1
    Join Date
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    Default 7Ah sealed lead acid current draw

    is there a table or chart that shows how much current can be safely drawn from small sealed lead acid batteries.

    trying to figure out how many i can put in parallel before having issues from the tiny connection posts on the batteries.
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  2. #2
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    Remember that this type of battery is rated at a 20hr rate. That is to say you will get 7Ah if you drain it to dead over 20hrs (7Ah/20H=0.35A). If you start pulling more amps the discharge efficiency goes down. As you can see in the typical graph below if you pull 1C(7A in your case) the battery would be dead in about 30min.



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    I am using some similar 9Ah batteries (UB1290) and putting 6 of them in parallel. I'm not worried about the 1/4" tabs since I will be pulling less than 50A from the pack (8.3A each battery). Each battery will have it's own 15A fuse and connected with 12 gauge wire. The 6 12GA wires will be ganged together to a larger conductor.

    So to answer your original question you can put as many as you want in parallel and not have to worry about the tabs. There are other issues like keeping the batteries ballanced.
    Last edited by Ted_Z; 01-25-2012 at 10:59 PM.
    -Ted Z
    '97 Grand Cherokee Laredo w/ stuff
    '07 Patriot Sport

  3. #3
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    Remember that the life of your batteries will be shortened if you discharge them beyond about 50% for captive electrolyte batteries (AGMs, gel cells) or 70% for flooded cells. Perhaps even more important is the fact that flooded cells can only withstand a few total discharges without becoming useless. (Perhaps the biggest reason AGM/gels are usually worth the extra money is that they'll come back from several hundred deep total discharges.)
    Mike Hiscox

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  4. #4
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    thanks for the info Ted.
    we used to use these in underwater equipment and used to cycle them a crazy amount of times from charge to max drain and did not have to many issues with premature failure.
    Bombardier Iltis, 1/4 ton M101CDN trailer, Hannibal 1.6 RTT
    http://www.iltisforum.com/
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