I got a price list for 20 1.2VDC nickel iron batteries for my 24VDC system;
300Ah is $5,100 before the cost of heavy wire connections and before the 40% Federal Tax Credit–if you qualify in income.(I don’t qualify)
The price goes to $14,000 before wires for a 700 Ah total set for 24VDC.
My 8 L-16S with two desulfators for two banks of 24VDC, 820Ah total. For a lower discharge figure (max discharge 30%) this is equivalent to the nickel iron 300 AH @ 85% discharge.
Total for my battery change with new desulfators was $2K, using the old cables. So if the desulfators double my battery life to 16 years, I am coming out well ahead of nickel iron with lead acid. Plus, I remember my book on lead acid batteries, that if I limit discharge to 20%, it triples battery life, too. Something to consider when designing systems is keeping the discharge at 20% instead of 50% as usual with system sizing for lead acid. And of course, the desulfators and equalization once a month and keeping distilled water fluid level well above the plates and near full all the time.
The nickel iron is advantageous if you qualify for the 40% tax write off, and if they are lower maintenance.
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