Ebike Motor Cutting out under load

[Endless squarer]

A few months ago I was riding my bike (36V 500W kit, Dillenger) up a relatively steep incline when it just suddenly cut off. It turns out I had blown the controller, one of the FETs to be exact, and I did not know this at the time. I ended up having to push the bike the rest of the way and there was a strong resistance in the motor (blown FET) but I did not realise. After some research and diagnosing the problem, I replaced the controller to a 48V 1000W controller, but in the course of adapting the connectors, and trying to see why this new controller wouldn't work, I left the phase wires and hall wires connected to the new controller while I connected the LCD and power cables to the old, blown controller.

Upon turning on the power, smoke and a spark sound emerged from the wires end of newly attained controller and long story short I realised why the new controller wasn't working (it had an anti theft cable which I needed to short circuit to get power to the LCD). But after all this and adapting the cables to the bike, when I took it for a test ride I noticed the power would cut out when under load( small hill) and the battery icon which gives me an approximation of battery capacity would blink with an empty battery icon, but the LCD wouldn't turn off. This would happen every 3 seconds and it would last about 5 seconds before the motor would start again, only to fail 3 seconds later.

I presumed it was the aforementioned spark and smoke which had damaged something in the controller so I ordered a new 48V controller, from the original manufacturer of my kit. But after connecting everything up and adapting the connections again, when taking it for a test ride, the motor again would cut out under load. I measured battery voltage to see whether that was the issue, but after a full charge the battery voltage is 41.7 which I would have thought was ok for a year old 36V battery.

I'm at a loss for ideas of what this could be and suggestions would be very much appreciated.

 

[Endless squarer]

Thanks amberwolf.

My display does not give any raw data such as wattage or voltage, but i'll try to measure this with dmm. Since phase/hall connections could also be the issue, i'll go through all 36 combinations this weekend and let you know the results.

 

[Endless squarer]

I'd been considering that myself as well Nelson. I originally had a 36/48V rated controller, but because that blew I thought it would be wise to go up. So a 48V controller could have a higher LVC than my 36V battery can output?

Sure Amberwolf, that seems a much quicker way

 

[docw009]

Yes, endless squarer, if you are using a 48V controller with a 36V battery, that explains it. A freshly charged 10S 36Volt battery is around 42.0 volts, and the LVC of a 48V controller is around 40.5 volts.

Some 48V/36V controllers will choose the appropriate LVC when reading the battery voltage on powerup. I have two that will do that, but they use the LCD-3 display, which does display voltage, and has tons of programmable settings.

 

[Endless squarer]

Thanks for the input, I think that must be where I went wrong. I'll look at getting a 36V controller instead.