Just about this time last year, I took delivery of a couple of SOK 12-volt, 206-amp/hour, LiFePO4 batteries in metal enclosures. I’d ordered them well before the van arrived, as SOK had none in stock, and no one knew when more would be available. They arrived a few months later, and are untouched, still in their sealed shipping cartons.

Our design has changed to use 24-volt batteries (sticking w/SOK, just more volts), so now these are extra. One has been sold, the other is available. I paid $1029 apiece a year ago. One year later, still brand new and unused, I'm selling it for $900, shipping included.

You can get a full run-down on them here.