E Bike Fault Finding

General Discussion about electric bicycles.
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globalzen   100 µW

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Joined: Feb 21 2016 11:31pm

E Bike Fault Finding

Post by globalzen » Feb 27 2016 11:44pm

Hi,

I have a newish ebike Chinese conversion that up until today has been working fine. I have put about 100km on the bike and absolutely no problems.

Today I loaned the bike to someone and it is now not working.

The lights power lights on the throttle come on, the battery is supplying the correct voltage, however there is absolutely no response from throltle input. I only use the throttle, no pedelec or input from brake levers are connected.

I have double checked the wiring and connections, there doesn't seem to be any obvious melts or connection issues.

I have taken the board out of the controller and there is no obvious problems or fuses.

The main fuse is ok (which is obvious since the power light is on).

Is there a better forum to be posting this on?

Where do you guys think the problem most likely lies - motor or controller?

Is there any tests I can do to determine which component has failed.?

Thanks in advance.


globalzen   100 µW

100 µW
Posts: 9
Joined: Feb 21 2016 11:31pm

Re: E Bike Fault Finding

Post by globalzen » Feb 28 2016 12:35am

Thanks Awesome - thanks

Let the troubleshooting begin!!

AussieRider   100 W

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Location: Seaford, Australia

Re: E Bike Fault Finding

Post by AussieRider » Feb 28 2016 6:35am

G'day Globalzen, welcome to the forum.
Is the fuse a glass tube type? I've had them fail where enough current could flow to light everything up but when I applied throttle the LEDS would fade out & no go. I think the wire loosens in the end caps. The fuse may look ok & test ok with an ohm meter but still have failed. Try a new fuse.

Hope this helps.
AussieRider.
Evolving E-bike
Retro style mid drive beach cruiser
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globalzen   100 µW

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Joined: Feb 21 2016 11:31pm

Re: E Bike Fault Finding

Post by globalzen » Mar 13 2016 6:06am

I have a non working ebike.

I suspect the controller is faulty and note that when the controller is attached and I spin the wheel in reverse there is resistance.

I have read this could mean I have a blown mofset.

The mofsets are labelled as SM7002N VN6BE

There are 10 of these mofsets in the controller. I can't seem to find a datasheet for these components, does anyone know where I can find the component datasheet?

The alternative is to buy another controller (I have no real idea of what to buy). What do you guys reckon - is it worth trying to fix this or just buy another cheap controller and hope for the best?

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dogman dan   100 GW

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Re: E Bike Fault Finding

Post by dogman dan » Mar 13 2016 6:27am

There will be some resistance when you turn the motor with a good controller.

If you blew the fets, then there will be a TON of resistance, and it will go away (to less) if you unplug the motor wire.

No doubt you know what you felt, and blew the fets. but the words you wrote don't make that clear. If you did blow the fets, you'll know. The resistance will be huge.

globalzen   100 µW

100 µW
Posts: 9
Joined: Feb 21 2016 11:31pm

Re: E Bike Fault Finding

Post by globalzen » Mar 13 2016 7:35am

My problem of course is that I don't have a functioning controller to compare it to.

There is a large difference in resistance between when I turn the wheel backward with the controller plugged in compared to when the controller is unplugged and I think this has changed since the bike stopped working but of course I never thought to officially test it when the bike was working.

Also, if you think a mofset is blown, is it normal for all of them to go - or should just one be damaged?

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LockH   100 GW

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Re: E Bike Fault Finding

Post by LockH » Mar 13 2016 8:06am

... and top of that list? A multimeter.
Image
ES changed my life (for the waaaaay better).

Eff. June, 2014 Phoenix Ebike Promotions

(Current ride? High speed lawn chair.)
viewtopic.php?f=3&t=57408

Phoenix Ebike Promotions conversion kit (work in progress. More drink holders, etc etc)
viewtopic.php?f=15&t=60564

Joined yer local chapter of EA yet?
(Ebikers Anonymous - Where we're all miserable failures, but the parties are hilarious...)

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