One 'large bank or two 'small banks

freecrfreecr Registered Users Posts: 1
Hi all, brand spanking new to the site. I want to set up a solar system for an RV. My question should be simple enough in essence. Am I better off to use one battery bank while the 2nd one charges, and then after a while (when at say 50% or whatever) switch it the other way, or is it better to combine the two halves into one larger bank and use and charge at the same time. Is there pros and cons for either. I can easily set up a controller to make before break to switch 'em back and forth. I would think giving batteries a little time off might extend their life plus if ever something bad happens only half the system suffers, but this seems uncommon so there's probably a reason.

Also to make it more difficult, one reason to ask is because I have some 75AH optimas that are 2 months old, and if I add more storage I'd like to buy and use some 125AH. Both battery types would be AGM. I know the difference isn't enough to prevent linking them. It's not optimal but should be OK.



  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    I seem to remember a similar thread over in the RV section about having 2 sets of batteries and one 21V and the other 24V, and ended up with one set ..have a look...

    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • lipetslipets Solar Expert Posts: 61 ✭✭
    KISS one bank
  • PhotowhitPhotowhit Solar Expert Posts: 5,658 ✭✭✭✭✭
    One bank, but a separator starter battery!
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former, 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • Alaska ManAlaska Man Solar Expert Posts: 252 ✭✭
    That's what I was thinking, one bank is enough to worry about. Why double the things that could bother?
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