Adding battery capacity

I recently bought two Revolutionworks 24V pedal assist units. Went to Burning Man and bolted them on to our junky old playa bikes. Worked very well for a couple of aging hippies. Problem is that they claimed 12 mile range with the 100wh model, but we got barely half that. They will sell me extra batteries, but only the small one will fit this unit. The charger is a fairly standard 29v brick and the charging port looks pretty standard. I am thinking of trying to get a larger battery and piggy backing it into the charger port. Revo says that won't work.

It could be made to work, but not simple, cheap or as safe / reliable as you'd want.

Just get a higher Ah capacity bank built that will fit on your frame, and figure out how to set it up to swap them out, or just make it your permanent battery.

The problem with using the charger port to parallel a battery thru is that if the current draw exceeds what that connector and wiring are capable of (probably very low amps, especially compared to the motor system's current draw), then it can damage the connector and wiring, potentially leading to a fire if the damage is the right kind (melted insulation leading to shorts).

Similarly, if there is a BMS on the battery, pulling that kind of current thru the charging port on it can cause the same kind of problem, with the additionall result that it can damage the port to where you can no longer charge the battery without replacing the BMS.


So I would recommend making a "Y-cable" to connect both batteries in parallel at the discharge connector.