Keeping lifepo4 batteries in a refrigerator

YerfYerf Registered Users Posts: 39 ✭✭
Do you think it's a good idea to keep my off grid lifepo4 batteries in a refrigerator while in use with a thermostat setting of 20c to prolong their life?

Comments

  • Raj174Raj174 Solar Expert Posts: 461 ✭✭✭✭
    For LFP life cycle, I think the difference in 20˚ and 25˚C is minuscule, and not worth the trouble. Although, colder temps would be recommended for storage, maybe 5˚ to 10˚C.
    12 x 300W Renogy PV, MNE175DR-TR epanel modified, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 195AH HI Power LiFePO4 no BMS, 4000W gen.
  • jonrjonr Solar Expert Posts: 858 ✭✭✭✭
    I'd do it if the ambient temperature commonly gets up to 35C.
  • mcgivormcgivor Registered Users Posts: 1,278 ✭✭✭✭
    If the refrigerator is powered by the battery it's cooling then the added load, if left on 24 hours, would probably have a negative effect greater than the benifits gained. If powered seperately, or using only excess energy during the day, then it may help.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • YerfYerf Registered Users Posts: 39 ✭✭
    Our temperatures can get upto 45 c outside. So I was thinking of putting them in the garage where it might be 35c at best, not good for the life of the batteries so I hear. So maybe I could use a small chest freezer and only switch it on when I have excess energy.
  • EstragonEstragon Registered Users Posts: 1,543 ✭✭✭✭
    I suspect having them in a fridge would be of some benefit even if the fridge is left turned off, as the insulation would keep the batteries at more like the daily mean temp rather instead of daily max temp. Putting them in a dugout or whatever might be even better, keeping them at more like seasonal or annual mean.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • YerfYerf Registered Users Posts: 39 ✭✭
    Do they need ventilation?
  • EstragonEstragon Registered Users Posts: 1,543 ✭✭✭✭
    I don't think so, but you'd want enough space for the batteries to disipate the bit of heat they'll generate in operation.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • BB.BB. Super Moderators Posts: 26,837 admin
    A good rule of thumb is for every -10C (-18F) decrease in temperature, a 2x longer life (storage life--Cycle life is probably not affected). At 0C, that would be 2x2=4x longer storage life... Conversely +10C increase, 1/2 storage life. Formula works for for just about anything.

    Used to try storing flashlight batteries in fridge decades ago (AAA-D cell alkaline). found that moisture/condensation ruined cells in fridge long before room temperature cells failed.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jonrjonr Solar Expert Posts: 858 ✭✭✭✭
    If you want battery cooling (more important with lead acid), consider using water that is only cooled while solar is available.
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