More Nickel Iron battery questions.

SaggysSaggys Solar Expert Posts: 173 ✭✭✭
Will be upping battery voltage this spring from 12 volt to 48 volt. Was going to go to 24 volt 250 amp hour Beutilityfree NiFe battery bank but came across a 24 volt 200 amp hour Iron Edison battery bank, both used but operational and holding a good charge voltage. Both of these battery bank jars are the same physical size, same amount of electrolyte according to the Changhong spec sheet. The only difference I can find is the 250 amp hour jar is slightly heavier. The question I have is how to series these up? I am thinking alternate them 200, 250, 200 etc.
and the bank will be held at 200 amp hour rating due to the higher internal resistance of the 200 amp hour jar. Or would it be better to go 20 in a row of 200 amp hour and 20 in a row of 250 amp hour? Or groups of 10? Or maybe it does not matter, I know it is advised to use all the same amp hour rating in a series string but I think I am going to try this anyway. I will keep my 24 volt inverter if it does not work out.


  • PhotowhitPhotowhit Solar Expert Posts: 5,989 ✭✭✭✭✭
    Why keep your inverter? Doubt it will handle the wide voltage range required.

    Posted this photo of the lie at Iron Edison about efficiency. Their charging range and nominal volt would indicate a max 72% efficency.

    So a 20 cell bank would charge at 33.3volts out of range for most inverters. So adjustable will work, but many will shut down, If you are still planning on using the PC250 charge controller, I think it's out of range too.

    I wouldn't mix to different age and capacity batteries in a bank, but please post your findings.

    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.
  • SaggysSaggys Solar Expert Posts: 173 ✭✭✭
    I am pretty sure my Trace PS 2524 is good to 33 volts, for sure 32 volts. The PC250 is good for 110 volts input. I will use a Blue Sky 6024H if I remain at 24 volt. Going to 48 volt will be a new inverter and charge controller, this point undecided. 
    Any way, back to original question,  would it matter how the series string is wired with mismatched amp hour batteries? I don't think it is going to be that big of a deal. 
  • SaggysSaggys Solar Expert Posts: 173 ✭✭✭
    I have the SWRC for the PS 2524 so it is adjustable. 
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