The thing is that even if batteries’ voltages are equalized, later during riding, under load, due to different internal resistance, the voltages will become a little different, which can cause current to flow between the batteries from the extra battery to the original one, so the original bms wrongly detects that a charger is plugged, sending a corresponding signal to the main controller, which will stop the motor until the battery voltages are equalized again after a few minutes so there is no more charging current. It is a real fail to suddenly find yourself in such “charging mode” at a traffic light.
This problem is solved by flashing a custom scooter firmware, where the charging mode is totally disabled. But there are 2 annoying things:
1. Actually, you have to flash the scooter. It’s not too easy for dummies, and also newest versions of the scooter are getting harder and harder to be flashed due to manufacturer limitations.
2. After disabling the charging mode, the scooter stops responding visually to the charger connection. It doesn’t beep, doesn’t show the percentage of charge on the screen, and doesn’t flicker with the tail light.
The supressor is a hardware solution which sorts out the “charging mode” issue. It joins the data exchange between the battery and the main controller, analyzing the battery current. The device checks if the current is similar to typical charging current and emulates zero value otherwise, so the controller does not enter the charging mode. On the other hand, if it looks like a charger is plugged – the emulator doesn’t change the data exchange, so the scooter gets charged as usual, displaying percentages on the screen and blinking by the tail-light.
Please remember, with this emulator you still have to match batteries voltage before joining them, it just makes it possible to avoid flashing the scooter.