Jerky wheel and blowing fuses

[Chris]

Hi, my bike has been going great, but today it started to blow the main battery fuse when the throttle was applied. Sometimes the wheel would jump quarter/half a turn before blowing. Also when you turn the wheel by hand with no power it turns with a 'notchy' feel as you turn it. Before I get the screw driver out, any ideas what I may want to look for? Thanks

[myelectricbike]

Sounds like maybe a bad controller or shorted phase power lead. You can test for shorts to ground using an ohm meter but shorts between phase power leads are more difficult to find. For those you have to open the hub cover and do a visual inspection to find the short. Use a keyword search under general discussion to find more specific and detailed information.

[Dalecv]

Disconnect the motor from the controller, then spin the wheel to see if it still feels jerky. If the wheel spins okay, then the problem is in the controller. If it doesn't spin freely then remove the wiring from the bike looking for damaged places. Where the wire enters the motor at the end of the axle is a stress location. If you can't find any wire damage then proceed into the motor.

Good luck.

[Dave]

Hi, my bike has been going great, but today it started to blow the main battery fuse when the throttle was applied. Sometimes the wheel would jump quarter/half a turn before blowing. Also when you turn the wheel by hand with no power it turns with a 'notchy' feel as you turn it. Before I get the screw driver out, any ideas what I may want to look for? Thanks

I discovered by accident that if two of the main power leads on the motor are shorted together, the wheel has that 'notchy' feel when you turn it (if all three are shorted, it feels like the brakes are on, but no notchiness to it). Do as Dalecv suggested & disconnect the motor from the controller & see if the notchy feeling is still there when you spin the wheel. If it is, I'd say that's good news, as it would most likely be a problem in the wiring going to the wheel.

[erdurbin]

The fuse that is included with the kit is a 15 amp. Cut that out and replace it with an inline 30 amp blade fuse. You can pick these up from Radio Shack. Also, with a blade fuse, you can find replacements about anywhere.

[Chris]

Thanks for all the replies. I disconnected the controller and the wheel spins fine, so it looks as though that is my problem. Are they a 'disposable' item or can they be fixed? Thanks

[myelectricbike]

Repair is a matter of cost. At $78 for a new regen controller you might be better off with a new one. Most electronic repair shops specialize and to do so means they have to charge a minimum which is probably $50. Otherwise, except for reprogramming the microcontroller, all the parts are off the shelf and can be replaced.

[Dalecv]

Sounds like an output FET has failed and is shorted. That is a common failure point with controller because all of the current that runs the motor flows through them. They are not difficult to replace if you have some basic soldering skills and are interested in doing such a repair. If you do a repair you can install better rated parts that would be less likely to fail. FETs cost about $2.50 to $5 and your controller probably has 6 of these and you should replace all of them even if only one has failed.

Here is a link to get you started if you are interested. http://endless-sphere.com/forums/viewtopic.php?t=764

It is much easier to buy a new controller, I don't know if a controller with regen capability is worth the effort and cost but that is another discussion.

[myelectricbike]

You will need to buy 12 if you replace all of them in the regen controller and the ratings of the mosfets used in either the standard or the regen controller are minimal at 75 volts and 82 amps so it will cost more to replace with any higher rating. Considering then that each IRFB4110PBF runs $6.21 from Allied you have already spent $74.52, not including taxes or shipping. However, you can upgrade a little for less using a STP120NF10. They only run about $1.27 each per thousand and are rated at 110A and 100V.

Update... I got to read Richard's post and he did a super excellent replacement job, not to mention the added effort to explain how to replace FETs. Don't know the current price of a Crystalyte controller but I can see why if the cost is much higher than a Golden where and why the need and desire to do this much work comes from. Still. if you want to do or have to do the FET replacements yourself and have the necessary skills, then his post is excellent, so go for it. Also be sure that the things he said he left out are not critical.