Can AGM batteries be reconditioned?

Discussion in 'The Garage' started by ass mysore, Jun 15, 2011.

  1. ass mysore

    ass mysore Been here awhile

    Jun 7, 2009
    Can AGM (aka dry cell, maintainance free) batteries be reconditioned? By recondition I mean using the "Recondition" mode on smart battery chargers that have this function. Mostly it's to break down the lead sulphate crystals by applying a higher current when the battery is fully charged, either in constant or pulse mode.

    Some articles I read on the net warn against trying to recondition AGM batteries, saying that it will lead to battery damage because the electrolyte is held in the glass mat, and overcharging disassociates the water from the acid, which cannot be replaced.

    Others say it's ok.

    So does someone know something about this subject who can advise me? Thanks.
  2. ttpete

    ttpete Rectum Non Bustibus Supporter

    May 13, 2009
    Dearborn, MI
    Just get a new battery and save yourself a lot of grief. Use a battery tender to keep it topped off anytime you're not riding it. Motorcycle batteries don't tolerate being deep cycled.
  3. johnjen

    johnjen Now, even more NOW!…

    Nov 28, 2001
    I have used the recondition mode in my 'smart' charger on my 10 year old odyssey. It still measures at 100% SoC is still in the bike and I see no reason to replace it, yet.

  4. Langanobob

    Langanobob Been here awhile

    Dec 23, 2006
    Well, if it's sulphated it's already damaged so there no harm that I can see by trying the recondition mode on a charger. I've never had any luck reconditioning any kind of battery but the chargers I've tried are kind of low end.
  5. alfred02

    alfred02 Adventurer

    Jul 9, 2011
    Australia N,S,W Mid North Coast

    I have worked with batteries for 30+ years, anything from NiCADS, NiMh, LiIon, LiPo, Gel, Flooded....
    Anything from car to hobby chargers to serious UPS's and now RF Equipment P.Supply/Chargers which cost thousands of dollars.

    Simple facts:
    1) ANY of the above batteries will loose major capacity and performance when cold
    2) No such thing as reconditioning......cycling a battery that might have become "lazy" can restore some or all of it's performance. You can do this simply by a few charge/discharge cycle...or simply charge and install in vehicle then drive it.
    This will create a charge/discharge cycle anyway.
    3) If you overcharge a's damaged, end of story. How much damage depends of by how much and how long it's been overcharged. So this could be a few percent loss to it's stuffed.
    4) Every battery has a finite life and two batteries of the same make and model, worked under the exact same condition can exhibit completely different life spans.
    4) Discharge a battery or let a battery self discharge below a given voltage and now is damaged.

    I have seen very expensive Deep cycle Gel Cells charged and discharged across some top of the line P.Supplies who cut off/disconnect the batteries at a minimum (adjustable) voltage fail, when the Cells in front of it and next to it would keep on going for twice the life span, i.e 3~6 years. Note this cells were hooked up in parallel, so each saw the exact same load and charge/discharge condition.

    So what does it come down to in simple terms for us, without getting too scientific and stay practical?

    1) Buy AGM Batteries. For the simple reason that they pack more capacity and cranking power for any given size.
    As they are built at a higher price, they also seem to be better build and more consistent in their performance from battery to battery.
    2) Don't keep cranking are dragging the battery voltage down and damaging the battery. 4~5 cranks and stop. If after 3 goes the car/bike doesn't's not going to happen and all you are doing is killing the battery.
    3) Don't leave your battery hooked up to a charger for days. The average charger is there to "charge" the battery and not to "maintain" the battery. Their final voltage/current is too high and will end up damaging the battery.
    All you are doing is making the electricity and battery supplier happy.

    What's a simple test for the none technical person to find out if the battery has had it?
    Easy...charge the battery then leave it for a week, if the bike/car after a week has slow cranking/short time cranking before the battery's toast... I don't care what type of battery it is or how old it is.

    Average battery life is around 3 years (if not abused) and everything else is a bonus.
  6. Wuwei

    Wuwei Long timer

    May 19, 2008
    New York
    Excellent short summary! Thanks.