Irving wrote:https://pushevs.com/2019/08/16/the-comeback-of-lfp-batteries/
I checked the link titled 2nd gen batteries 190 euros perkWh.
Price seemed quite low. Must have really come down since BM did his 1st build.
One thing though is they are sold in groups 4,8,12,48 as needed for ~12v groups of 4 lifepo4 3.3v cells BUT when you click on the specification these cells are shown to be Li-ion cells which would be 3.7v or a 3 cells group for ~12v.
They probably really are lithium IRON phosphate but the spec link gives me pause as usual.