The real test is to make an extended drive in that electric DeLorean in very cold weather where you need to recharge the batteries.
Conversions like this are by default modular. Sodium ion cells are coming into bulk production. Sodium ion doesn’t lose power density at low temps at all and they have full discharge capacity st minus 40C very few places see that and the ones that do can insulate the case the self heating during charging and discharge is more than enough to keep the cells above minus 40C with a few inches of R30 or higher foam. Sodium cells also take 50,000 cycles to 80% SOH ten times LFP and fifty times NMC cells. The cathode and anode both are cobalt,nickel and rare metal free. They just now are getting to a energy density of 160wh/kg that’s LFP territory and plenty good for a run about conversion like this. Oh and sodium cells with Iron/manganese cathodes cannot burn they use water based electrolytes and sodium salts plus have massive 20C plus charge rates that’s 3 min from zero to 100% the only cells other than aluminum graphene to pass 20C and still keep 50K plus cycle life’s. Lithium ion is a stepping stone to better cells. Sodium cells are going to be the dominate cells in power tools, and personal electronic device market regardless of EVs they beat lithium in every metric possible other than energy density and they are closing that gap fast. The theoretical max for Na ion is in the 500wh/kg range and the cell tech is less than 5 years old lithium had a 30 year head start.