When troubleshooting your electric bike battery, the first thing that comes to mind is usually an ohm meter or a load cell. These are electrical devices that measure the resistance that is created in the circuit when current is applied. Simple enough, but unfortunately they are not very useful for troubleshooting your electric bike battery. The reason is that they are designed to measure only the resistance, which is present both while the electric motor is running and also after the motor has shut down. The reason that they are used in this way is that they do not measure the power that the battery develops during operation.
How do you use these two measurements to measure the current of your e-bikes battery? Simple, just take the Ohm measurement and multiply it by the measured battery’s amp hours (AH). For instance, if your battery’s Ah rating is 24, and its amps hours is 10, you get 240V / 10 Ah = 12V / 2.8A = 8.4 volts per cycle. This means that the battery can produce up to 8.4 volts per cycle if it is charged and discharged properly, so if the Ohm meter reads either low or high, it is probably just the amp hour that is low and not the actual current. To measure the current, connect a load cell or an ohm meter to the input of the charging unit and use the load line to see the output, which should read zero.
The final measure that we will discuss here is the output of your charging unit itself. You can monitor this by connecting a multimeter to the input of the charging system and using the potentiometer to adjust the charging rate. If you notice a gradual decrease in the output as the charging progresses, this means that the battery’s capacity is slowly decreasing. You might want to consider increasing the charge rate until you notice a maximum in the output. If you’re unsure about which is the correct setting, then simply set your multimeter to measure the resistance of the charging system rather than the current, since resistance has nothing to do with battery capacity.