I had a 200 watt geared mini-motor with a 36V 30Ah LiFePO4 battery installed on my modest road bike. The kit was installed by Solar Bike and had the battery attached along the crossbar (part of a research and development project). I was informed that deep discharge of the battery can cause serious damage and added a cycle computer ($50) so that I I could gauge the battery level from distance travelled. I also added an isolation “heavy duty” 24V@38amp truck switch ($20) to prevent deep discharge if the bike was left on for a long period of time.
After two weeks of immense enjoyment, never having to break a sweat or pedal hard up a hill and telling everyone who was interested about the joys of electric bikes I had a bit of bad luck; unfortunately, the motor failed. I returned the bike to Solar Bike who were extremely happy to help. When I explained that I had been assisting/pushing my girlfriend up a hill to avoid her needing to pedal by providing “powerpacks”, we agreed that I had probably over-heated the system and burnt out a hall sensor in the motor. Having being totally satisfied with my kit until then and willing to purchase a new motor, Solar Bike insisted on replacing the burnt out 200w motor free of charge as they assured me that the motor shouldn’t have burnt out and it may have been faulty.
I upgraded to a 350w motor and have been riding this new combination for over a month now and am extremely impressed and satisfied with its performance. The 350w motor produces a top speed of about 30km/h which is only 10% faster that the previous 200w, but most of the power is transmitted as torque which means it can push or pull harder. This gives me more comfort that I won’t burn a motor out again. However, I have set myself a rule to stick to keep it running in its intended torque range and under heavy load conditions (uphill/into wind/ pushing another cyclist) on full throttle, to ensure a constant velocity of 20km/h or greater is maintained by pedalling. I have been sticking to this and have had no problems to date. I have been able to achieve a range of 45km from a single charge and have already travelled hundreds of kilometres since it was recently installed.
Emil Taylor B.Eng. (Hons)