Can AGMs and Gels be successfully mixed?

softdown
softdown Solar Expert Posts: 3,895 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
Charging recommendations are the same with Outback. That leads one to ponder the feasibility.

I have six good AlphaCell/Outback 109 Ah Gels. An unwieldy number in a 48 volt system. They currently want too much money for two more Gels.

I'm pretty sure that mixing them is not optimal. But is it possibly practical in some cases?
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
· Share on Twitter

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    IF you are going to mix... This is what I would try:

    Drop charging voltage down to 14.2 volts (or the lesser of AGM vs GEL charging voltages).

    Get a DC Current Clamp DMM (digital multi meter like this one from Sears, or better).

    Review the recommended charging voltage/current for the GEL batteries and use the current clamp meter to make sure that you do not exceed the maximum recommended charging current for the GELs.

    Most US GELs are listed for 14.2 volts and C20 (or 5%) maximum charging current.

    Did the GELs you have list a higher charging current (I forgot)?

    If your GEL+AGM play well together, and you can charge your system/batteries correctly (with available hours of solar and charging current)--I don't see why you cannot try it for a while and see how it works.

    Many GELs are designed for "float service" and do not like deep cycling or daily cycling... Review the specifications/talk with support department and make sure they are OK with your application.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • softdown
    softdown Solar Expert Posts: 3,895 ✭✭✭✭
    #3
    A few of us tried to find charging recommendations for my AlphaCell Gels....with no luck. I called AlphaCell and was transferred to Outback. Their rep informed me that a bank of four 109 Ah AlphaCell Gels could handle about 22 amps of charging power.

    I can't get any more AlphaCells via their web site information. Tried many times. No AlphaCells seem to be available in Colorado either. Tried a few times. Similar gels are very expensive. I'd rather just buy a couple big AGMs at Sams Club and try my luck I think.

    Or maybe the thick plate AGMs that were posted a couple days back? Don't know about shipping fees however.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
    · Share on Twitter

Categories