This design makes it easier to replace golf cart batteries, wheel chair batteries, trolling motor batteries, solar storage, etc. with a long lasting lithium chemistry. The finished battery is robust and attractive and can be used without a case.
The 26650 size is readily available in the LiFePo4 chemistry.
This means that when you put four in series you get the voltage of a 12 volt lead acid battery.
Shop BatteryHookup for 26650 LiFePo4 cells. You’ll need 120 of them.
This battery with these cells has 96 amp hours and 12.8 volts for 1,228 watt hours. and costs around $450 with cells.
You get all the pieces you need to assemble the battery as shown.