Measuring current usage in a wheelchair power assist device
The idea is good.
I think you should compare Energy consumption instead of current consumption.
You will need 2 recording digital multimeters.

In order to estimate the energy consumption you need to measure and log the battery voltage as well.
Plot in Excel the function V(n) * I(n) and sum it over n.
You will get the total energy consumed over the observation time.

There are plenty of recording DMM digital multimeters.
Use a recording time step of 0.1 seconds or greater.