AGM EQ gassing noise vs. venting hiss?

PNjunction
PNjunction Solar Expert Posts: 762 ✭✭✭
in Off Grid Solar & Battery Systems #1
Before I invest in something like Lifeline agm's that allow for occasional eq, I wanted to know if they make any noise internally during the eq process?

To learn the difference, I have taken some non-critical Optima yellow tops to 15.5v for a period of about 30 minutes after a full charge, and witnessed light crackling and sometimes small popping, much like having the battery filled with breakfast cereal and milk poured into it, and have never been brave enough to to take it far enough for an outright blown vent, steam, or hissing. I could hear it from only about a foot away from the battery while wearing a welder's face-mask for safety.

Still, I wonder if I have blown a vent, even though nothing dramatic seems to have happened. The battery stayed cool too, only measuring about 5 degrees above ambient. While Optima doesn't seem to condone EQ, I did it anyway just for educational purposes.

Essentially I wanted my ears to know the difference between normal EQ sounds, and outright steaming/hissing which I'm too chicken to actually do. Does just light breakfast-cereal crackling sounds seem normal under an EQ for an agm that can actually do it?
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    Re: AGM EQ gassing noise vs. venting hiss?

    I think when AGM's "snap, crackle and pop" (or any sound,) you are doing something wrong. I also don't think AGM's are supposed to be "equalized" except as an emergency recovery effort before tossing them out as scrap.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    Re: AGM EQ gassing noise vs. venting hiss?

    Generally, "equalization" for AGM batteries is just normal absorb charging voltage carried on for a few hours longer than normal--As I understand (and should not be done often).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: AGM EQ gassing noise vs. venting hiss?
    Lifeline agm's that allow for occasional eq

    Three key segments to that: "Lifeline"; "allow for"; "occasional".
    Not: "Optima"; "do not EQ AGM's"; "purposefully cook at too high a Voltage". :p

    If Lifeline has a recommended EQ for their AGM's follow those instructions on those batteries. Whereas all lead-acid batteries are similar in nature, they are not identical.
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  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    #5
    Re: AGM EQ gassing noise vs. venting hiss?
    BB. wrote: »
    Generally, "equalization" for AGM batteries is just normal absorb charging voltage carried on for a few hours longer than normal--As I understand (and should not be done often).

    I think you convinced me. An extended absorb has worked well for me before, and was simple enough to do via solar by just setting my CC's absorb and float voltage to the same value, and letting it stay there for a few hours longer than the usual amount of time it takes to get down to .02C or thereabouts. (no load). I've even taken absorb a *tad* higher than the usual - say the manufacturer spec is for 14.6v normally, I'll run 14.8 with an extended absorb (temp compensated of course) and stop things manually. My Xantrex/Schneider C12 makes doing that easy.

    It sure seems a lot safer than the 15.5v treatment, and I just freak out when I hear the snap crackle and pop. :) And if I'm dealing with a hard-sulfated battery, then I'll just buy a new one, and try to treat it better.

    After hearing the Optima complain at 15.5v, I think I'll stick to the extended absorb technique if I feel it is really necessary.
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