48V to 60V diagram. Need some advice

Hello all,

I'm new here, so apologize if a similar topic had been already discussed.

I recently bought myself a new "project". It's an older Chinese electric scooter with only 70km on it. It has 4 dead 12v 17ah batteries, 700w brush motor and an unidentified controller. Looking at the wiring, it looks like one battery is used only for lights and switches, while the other 3 actually provide 36v and 700w to the motor. Now, my questions is, what if I use all 4 batteries in series and create 48v at 20ah (i just ordered 4 12v 20ah sla) and add a smaller battery for the lights? I'm assuming that the motor and possibly even the controller should be able to handle it and I would only need to replace the charger with 60v one? Also, the smaller battery could probably be 10AH? Please see two schematic pictures in the attachment.

Thanks!

It would be very unusual to not simply already have all four in series.

If it actually uses one 12v system and one 36v system, that means it also probably has two charger ports, one for a 12v charger, and one for a 36v charger. (because the batteries would be used at different rates, so they cannot be charged as a single 48v pack and discharged as two separate ones, without damaging the less-used battery from overcharging, or never fully charging the more-used battery).

If it does not have two charging ports, then it is probably actually wired as a single 48v system.

Then there is probably a 12v dc-dc for the lights, if they are 12v, or else they just run off the main pack directly if they are 48v lights. (both systems exist).


Can you post photos of the actual wiring on the top of the batteries? (rather than the drawn diagram)

Does the controller itself have any markings on it?