Battery Bank Basics: Lead-Acid vs. Lithium

Your battery bank decides how much of your solar production you actually get to use. The two chemistries home builders choose between are flooded or sealed lead-acid, and lithium iron phosphate.

Lead-acid is cheap up front and forgiving of over-discharge if you watch it. The trade-off is usable capacity: you only get about half the rated amp-hours before sulfation starts.

Lithium iron phosphate costs more per amp-hour but lets you use 80 to 90 percent of the rated capacity, weighs a third as much, and lasts far longer in daily cycling.

Match the chemistry to the charge controller. Lithium needs a controller with a lithium profile; a lead-acid setting will undercharge it and shorten its life.

Temperature matters. Lead-acid survives freezing; lithium should not be charged below freezing without a heater.

For a full bank sizing worksheet and parts lists sized to your loads, the Energy Revolution System is the guide we recommend.