Mixing Batteries

System
System Posts: 2,511 admin
in General Solar Power Topics #1
Hello
The existing lead-acid batteries(type 27, 90ah/175min)) in the system were never allowed to discharge more than 10-15% (3 of them) and used for approx 6 months, then stored and maintained with h2o and trickle for approx 18 months. I would like to add ($$ reasons, never enough) 2-4 new type 29 marine/rv batteries( 125ah/215min). I know that mixing and matching is a no-no but i am close on everything i was wondering if i could get away with this? The delta is 25ah/40min
I will be replacing these in the near future with AGM's (all the same, lol).
Thank you and happy trails to all.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    Re: Mixing Batteries

    Sure you can do it, but why. Run the tired set into the ground (but they don't sound all that tired, they may last you a good while) See what flaws you discover with them (after 2 days of wind, they overcharge and boil) and apply that knowledge to your new AGM's.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • System2
    System2 Posts: 6,290 admin
    #3
    Re: Mixing Batteries

    Hi

    I am no expert by any means on hybrid power system. What did you mean by 2 days of wind and boiling and such?

    thanks

    jerimiah
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #4
    Re: Mixing Batteries
    jerimiah_jetson wrote:
    I am no expert by any means on hybrid power system. What did you mean by 2 days of wind and boiling and such?

    It's a failure mode, say if you have a wind charger, and a couple of real windy days, it's been cranking out 1KW for 48 hours, and the batteries are full - 100%. Put anymore juice in, and they start to boil. When it's intentional, like an equalization charge, it's not a big deal, but if something unintentionally happens while you are gone for a weekend, or just sleeping, it can become a expensive mess. Until you "learn your system" I'd suggest you use the batteries you have, and work with it, as it exists, for a while, and then see where the weak spots are, rather than just tossing some $$ in the form of new, unmatched batteries, which never works well.

    Mixing batteries, never works well. Sometimes, it will just work. Often it's a way to ruin the new batteries.

    We here in cyber space, have no idea what your setup is. Solar, Wind, Hydro? How long you need to run with out recharging, etc......
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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