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Tuesday, September 8, 2009

Pop Goes the Breaker

I'd installed a 25-amp circuit breaker between battery pack positive and the rest of the system, as I thought it would be helpful to prevent potential short circuits, given my jury-rigged wiring and stuff. It turned out to not be nearly enough for the startup-from-complete-stop power demands of this motor.

Having the breaker pop as I pull out into traffic to make a lefthand turn is very bad. :( Can still pedal but it's really hard without the motor, unless I have time to flip the clutch lever to disengage the gearbox! Like going up a REALLY steep hill. One reason I still keep considering a shift-lever cable-actuated clutch disconnect. (Another reason is possible motor runaway should a controller fail short circuit).

So I took the breaker out. I'll have to live with the risk of wire harness shorts, and just minimize them as usual. Better that than getting hit by a car!

I suppose I could put two or three breakers in parallel, but I'm not sure how well that will work if something *does* short.

I would use one of the 100A fuses out of the UPS, but I prefer something resettable, so I don't have to dink around with wiring around it if it gets blown on the road somewhere, either because of a short or because of a motor overcurrent, that I can fix.


  1. Eek!

    I did that on Jobike2. I had two 40amp breakers in parallel.

  2. That was eek! about the breaker poping when pulling out in traffic! 0_0


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