No power to motor problem

[Mark Barraclough]

My bike seems to have developed a fault and I was wondering if anyone could point me in the right direction to track it down. I rode home the other morning fine and put the bike on charge. When it came time to go to work the battery appeared to be charged and the charger light was green. Upon getting on I found that the motor was not running and several times upon turning the key to the "on" position resulted in a clunking noise and the power indicator on the handlebars going off. I have not had the chance to track down where the clunking sound is coming from, the hub or the battery but will be investigating further in a couple days to try to repair whatever the issue is. The power does not always go off when turning the key though it still wont run, and when it stays (most times) on the battery indicators on both the handlebar and the battery housing indicate a full charge, plugging the battery into the charger gives a green fully charged light. The bike is a 3e Urban and has served me well since buying it last year so I'm hoping to have her up and running again asap.

any help would be appreciated and thanks in advance,

Mark

 

[Deleted member 4366]

Has it always worked perfectly, and then one morning it didn't work, or has it done this before?

What do you have on the handlebars that tells you the charge state of the battery?

Do you have a LCD or LED panel to select different pedal assist levels?

Whatever is the cause, you will most likely need a multimeter to find it, so if you don't already have a multimeter, you should get one now. You can get one from Maplin, any DIY shop or Ebay.

http://pages.ebay.com/link/?nav=item.view&id=360538749861&alt=web

 

[Mark Barraclough]

Yes it worked fine with no problems before this, i have a 3 led indicator on the handlebars, the bike doesn't have assist levels, but does have a twist and go on the handlebars. After further investigation it is looking like the back wheel is the problem as the power is getting as far as the connector from the battery to the hub. I think the motor maybe be seized in some way.

 

[Deleted member 4366]

There's nothing in the motor or motor wires that can cause that problem because there's no power in the motor wires until you open the throttle or turn the pedals. I would say that you've got a short somewhere between the switch and the controller. If the power cut every time you switched on, it could be a blown FET in your controller, or if it cut every time you used the throttle, but I wouldn't expect that fault to be intermittent. If you can measure battery voltage on any of the three motor wires, a FET is blown.

To test the FETs you need to disconnect the controller and measure the resistance between its red battery wire and each of the three main motor wires, then again with its black battery wire to get six results in total. There's capacitors in there, which might discharge to give changing results, so it's best to do one quick measurement of each.

You can test for a short by disconnecting one of the controller battery wires and sticking a fuse between them. If it blows when you switch on, there's a short downstream. If it doesn't switch on, your problem is upstream.

The most likely upstream cause would be the key-switch or its wires shorting.

 

[pdarnett]

I may have a spare controller for this bike Mark. I've pm'ed you with some things to try, but I'm only down the road if you want me to diagnose.

 

[Spudmurph80]

Hi There
I do apologise for jumping in but I have a question about my bike , I bought a Bafang bbs02 36 volt 500 watt motor the new version and I was told I could over volt the bike with a 48 volt battery which I did do but finding this does not work , I have now been told I would be better getting a Bafang 48volt 500watt controller and exchanging it for the 36volt , my question is this true and would it work fine or would I have to do something else to make it work.