Known Problems with the C5

1. Commutation diode failure. If the vehicle is pushed backwards at anything other than a very slow rate, the motor which is rotating as a generator forces a high current through its commutation diode which then blows open circuit. Without this component, bad arcing will occur at the relay contacts during switching leading to rapid failure.

2. Relay contact failure. Generally due to the above. Contacts can weld closed causing a "run away". The emergency battery cut-out is essential to prevent this hazard.

3. Electronic component failures in the control box. The LM358 dual OpAmp in the control box can fail, probably due to large voltage transients on the 12 volt battery supply during accidental disconnect.

4. Electronic component failures in the pod. Virtually all the circuitry is provided by a single integrated circuit. This chip obviously cannot be repaired. The robustness of the pod can be increased by fitting a resistor of value 10 K Ohms in the lead feeding pin 6.

5. If corrosion of contacts in the electronics is noticed then reliability and function could well be compromised.

6. The front wheel being plastic can absorb very little braking heat. Softening of the rim followed by inner tube burst out is known. If a steel rim can be found this provides the best solution.

7. Rear brake. A tendency to lock on (digital breaks) is obvious. I'm not sure of a cause as I've seen it happen straight after a new brake assembly was fitted. This cannot be due to pin wear and must therefore be some sort of self servo action due to the geometry of the parts.

8. Drive belt and pinion wear. Due to slackness or excessive tension. The latter causes the motor to tilt slightly loading one edge of the belt very heavily. Never start the C5 under power but always pedal a little first. The stall torque of the motor is very high and strains the transmission significantly.

Contributed by Perran Newman.