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AGM Batteries - Making The Choice

Discussion in 'Musings With Maine Sail' started by Maine Sail, Dec 6, 2010. Add this thread to a FAQ

  1. JimInPB


    Joined Aug 22, 2017
    696 posts, 199 likes
    Hunter 212 & 170
    us West Palm Beach
  2. JimInPB


    Joined Aug 22, 2017
    696 posts, 199 likes
    Hunter 212 & 170
    us West Palm Beach
    Wow, TONS of good info in that write up. Thank you for posting.

    The above paragraph does leave me with a question. It's been my experience that after a battery has sat at PSOC for more than a day or two, the self discharge rate tends to go up noticeably. I have always assumed that this comes from sulfate bridging, but I have no real proof of that. If the battery (especially a cheap one) is left to sit for a longer period of time, the effect seems to accelerate.

    Have you noticed similar increases in self discharge rate?

  3. Rick


    Joined Oct 5, 2004
    991 posts, 1 likes
    Hunter 420 Passage
    US San Diego
    And then there is Lithium. Maine Sail does not consult on lithium, but he can "water your eyes" with um "stuff" about them. Also a plug. He has a lot of stuff that all of us need for sale electrically on his site.
    Great article! I dont have AGMs but I read every word.

  4. Bob S

    Bob S

    Joined Sep 27, 2007
    1,361 posts, 27 likes
    Beneteau 393
    US New Bedford
    I just purchased a Northstar Group 27 AGM for a start/reserve battery and six GC2's for the house.
    1. Do you do anything to commission the AGM? This battery will most likely never be needed and will be fed by an echo charger (I am following your advise for the 6V in parallel from another thread)
    2. Is it recommended to use a battery box for a single AGM? I was thinking of fabricating an aluminum base that can be fastened down and use two stainless steel threaded rods and a bracket to hold it down similar to that used in cars.

  5. JimInPB


    Joined Aug 22, 2017
    696 posts, 199 likes
    Hunter 212 & 170
    us West Palm Beach
    Yea, Lithium, can be a great performer with a great power to weight ratio, but you need to have the right guy keeping an eye on the system & you need the right kind of cell-level monitoring as well as the right kind of charger. When bad things happen with Lithium systems, the results can be catastrophic.

  6. Gunni


    Joined Mar 16, 2010
    4,913 posts, 861 likes
    Beneteau 411 Oceanis
    US Annapolis
    An AGM does not require a battery box, BUT I have my starter battery in a box because it is in my engine bay where falling wrenches, tools and miscellaneous engine parts could possibly contact the battery cables and cause a catastrophic short. It was also easy to grab one off the shelf and strap it in.

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