I’m in the process of upgrading the electric go-kart I built last summer to a beefier motor and using some salvage-but-in-good-condition battery modules (each module is a 12S pack of 20Ah Lithium Titanate cells). I have six such modules so combining them in two parallel strings of three modules would give me a 36S2P arrangement allowing for a nominal 72v (92.5-ish open circuit at full charge down to 54v when it is close to empty) with a 40Ah capacity.
This is, I realize, vast overkill for a go-kart as it would give me a full hour of pedal-to-the-metal operation up a fairly steep hill so I may just use one string and reserve the other for a different project.
My question is this: does anyone have a recommendation for a 36S Lithium Titanate charger? Each 12S module has a monitoring board that reports the cell voltage of each individual cell over CAN every few milliseconds (along with some other data I have yet to decide). The board in each module clearly contains the balancing circuit but short of deliberately unbalancing a pack to see what it does I can’t be sure whether each pack autonomously balances when being charged or if it merely reports status up to the donor wreck’s main computer and the main computer sends it back messages telling it which balancing action to take on which cell and when.
The upshot is that even if they don’t auto balance I can at least take control by programming a microcontroller to watch the CAN output and shut the charger down when the first cell reaches full charge (and, of course, tell me which one so I can bleed some charge off it and the finish charging the rest) so I don’t strictly need a balancing charger nor do I need one that’s capable of quick charging them (a 10A or 20A charger for 36S would meet my needs quite well). Any recommendations?