Help! Giant Prime motor cuts out after a few seconds

[kevin30b]

I have a Giant Prime + of circa 2015 vintage with an oblong display mounted centrally. The long side of the display is parallel to the handle bars. The motor is made by Yamaha.

When I turn it on the display comes on normally. The throttle works normally and the motor assists whilst pushing the bike.

When I try to pedal the bike the torque bar shows increasing torque, then the battery state of charge bar graph starts to flash. After a number of flashes the display becomes stable apart from the second segment in the bar graph, which continues to flash.

Does anyone know what this means? There are no error code numbers on this display (I don't think it has any?) and Giant are unable to supply any information.

I was hoping to change the display for one with more diagnostics but have been struggling to find any information on compatibility.

 

[cyclebuddy]

My guess would be a knackered battery. At 7/8 years old it'll be well past it's prime, and what you say about pedaling/applying torque suggests the voltage is sagging to the point of cutting out when you're demanding high current from it. The battery may well behave better if you only pedal gently without demanding too much. If it were my bike I'd have the battery tested and/or be looking to replace it at that age.