The EM100 was upgraded to an EM150. This was simple, basically a straight swap for the old EM100 motor controller. However, in an attempt to program the new controller the parameters for the old EM100 controller were lost. I emailed QS Motor to try and obtain software for changing these parameters to ensure a smooth motor control system could be implemented. I was only given a poor-quality version of the software I could already find deep in an emoto forum (, so determining how the program worked was time-consuming and not fruitful.

This new speed controller worked at low accelerations. However, when the throttle was rapidly changed the acceleration showed a visible drop in the battery voltage and the whole bike would not function until recharged. What was happening? Likely an overcurrent or brown-out event occurred causing a shutdown of the whole system. This was more likely to occur after discharging the battery (by riding) so is more likely to be a brownout type event due to limited battery capacity or battery amperage delivery potential.

The next step is to upgrade the battery, BMS, and battery charging system to ensure this isn't a bottleneck for the rest of the system. 144pcs 18650 batteries have been purchased to add to the existing pack of cells... TBC