Nickel-Iron Battery/User's Manual

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  • Dead discharge for years does not hurt the battery? [1]


  • From a Russian patent - It appears that carbonate crystals form on the electrodes, but these can be shaken off by draining electrolyte and filling with distilled water, then going through electrolysis which heats the water and gas bubbles shake the carbonates off [2]
  • Where does carbonate come from in nickel iron batteries?
    • From the atmosphere - carbon dioxide in the air dissolves to make carbonic acid, and the basic electrolyte reacts with the carbonate to make KCO3? - U. Chicago - [3]
  • Video on how to replace electrolyte - [4]


From [5]

  • Water top-ups once every 1 to 2 years
  • Full electrolyte change every 10 years
  • A "de-carbonating charge" (by shorting out the + and - electrodes and using that metal case as the new negative electrode for 1x full charge cycle) every 20-25 years


  • They electrolyze water, so water must be replaced.
  • Add a little LiOH to reduce gassing by reducing internal resistance, increase life and capacity? - [6]
  • Refilling period - 3 times per year in this one - [7]

Electrolyte Replacement

  • KOH is $2/lb - this should not be expensive.
  • Lithium Hydroxide is added?

Are they really good?

  • Encell data, cost per kWhr over life is 3x better than LiIon and Pb acid - [8]
  • Good jar experiment that one can try - [9] - mentions nickel (II) hydroxide and rust (Fe3O4 - Magnetite.)
  • Comment from user - the Chinese versions suck - [10]
  • P. II-27 says Lithium Hydroxide is used in small part in electrolyte [11]
  • Cost of LiIon is down to $100/kwhr [12]
  • Under deep discharge of 60-80%- Westinghouse is getting only 1600 cycles. So do they degrade like lead acid? Maybe not as bad, but nowhere near the 30 years of deep discharge. Note - new tech showed 3000 cycles at 100% dod, see main page on NiFe. -II-28

Cold Temp

  • See performance curves - [13]


  • 3.2kg of nickel per 1 kwhr p. II-32 [14]