Motor problem

[boots]

My motor kicks in every now and then when not peddling, its done this pretty much since I got it, friend says I must be moving the peddles and indeed I can make it do it when I swing the peddles or back peddle but it will also do it when completely stopped at lights or in traffic, it'll just be the odd soft vrrrm or sometimes a series or vrrrms, and then nothing for ages. Haven't been that bothered by it.

The poor bike fell over a couple of weeks ago, the handle bars got knocked and I found a hairline crack on the bit the battery inserts into, the crack may have happened from a previous fall but otherwise she seemed ok so off I went on my trip, no incidents. When I got to my destination I got off to park up and all of a sudden the motor just went potty, I was on full assist so this was much more than a little vrrrm, I switched the battery on and off a couple of times and it kept doing it, so I let it be but as soon as I switched on to come home it did it again at full speed.

I wondered if somehow I'd damaged the walking mode button which takes you to 6kmph without peddling but when sitting on the bike it was much faster than that. It did it intermittently all the way back and intermittently on subsequent trips and then goes back to normal.

Its done the small vrrrms today and that's put it in mind to ask you guys for some advice. The bike is an EB6165 from erolling, it doesn't have a throttle although I'd wished it had, so have possibly jinxed it in some way. Also possibly connected is uneven motor response from the peddles, the left one gives vrrm and the right one vrrrrrrrm, friend just raised an eyebrow when I mentioned that. Please help this novice.

 

[boots]

Anyone got any idea? Is it mendable?

 

[Deleted member 4366]

That's not a common bike. We need to know what it is to be able to fix it. I guess it's a Chinese import with standard Chinese electrical bits, but which ones? Please post three photos: The whole bike; the handlebars to show the control panel; and the back-side of the chainwheel to show the pedal sensor like the photo in this one:

http://www.pedelecs.co.uk/forum/threads/upgrade-your-cranks-for-£66-or-less.15682/

 

[boots]

I managed to get photos earlier in between the rains and then popped out to do some shopping. I was just looking at them to upload and heard a huge crash, bliddy thing fell again, my fault as was chatting with neighbour at the bike and put her cover on but forgot to put the lock, so it fell inwards pavement / chain side instead of the usual into the road side, looks like the peddle took the brunt of the fall, took her round the block and all seems ok. I'm sure all these fallings can't be good.

The bike is indeed Chinese, hopefully here are the photos:

 

[Deleted member 4366]

The photos are perfect, thanks. It makes a change. I often have to ask four times.

I have some ideas about what's wrong, but a bit more investigation is necessary. I suspect that you have/had water in the control panel, which should be easy to see if you can get it apart.

The panel can be wired up two ways. One way, it gives a signal (fixed voltage) to the controller to tell it how much speed to give when you pedal . In this mode, the pedal sensor is wired to the PAS connector on the controller.

The other mode has the pedal sensor wired through the panel. It then gives an analogue output, which is like a variable throttle signal. I reckon that this is how yours is wired, because it would account for your random surges, which are otherwise hard to get without a throttle. I'm not sure how reliable it is wired this way. I know Parnett had trouble with his, and had to buffer the signal from it, but he didn't have a properly matched controller.

I think, I'd eliminate the obvious first by checking for water. After that, is there anything that can cause interference like a wireless cycle computer?

 

[pdarnett]

I think the same as you Dave, the panel does the work of turning the sensor output into a throttle signal so I think water has probably got in there, I've had mine in bits and there wasn't a seal or anything to stop water getting in so i put a small bead of black silicone around it to stop water getting in before i put it back together again. plus I sealed the cable entry point.
It's quite a cheap part to replace though, it's this one http://www.greenbikekit.com/motor-controller/led-display.html

 

[boots]

Well I spent a good while on my knees in the street looking intently at the cables and the panel, I am surely not the first to say why are the cables not marked? its like spaghetti and they all go inside the frame and out of some different hole or is that other hole???
I did find two weeney screws underneath the panel so I need a tiny x head screwdriver to open it, then it rained.
I have a wired speedo and it was warm and sunny when I got the bike and there was no rain for at least 3 weeks from it arriving, it was already doing the intermittent thing before any rain arrived, also I do wear full steelies could that be a factor?

 

[boots]

I think the same as you Dave, the panel does the work of turning the sensor output into a throttle signal so I think water has probably got in there, I've had mine in bits and there wasn't a seal or anything to stop water getting in so i put a small bead of black silicone around it to stop water getting in before i put it back together again. plus I sealed the cable entry point.
It's quite a cheap part to replace though, it's this one http://www.greenbikekit.com/motor-controller/led-display.html

Thanks for that link

 

[Deleted member 4366]

The wiring is more simple than it looks. All those wires end up in the compartment on the front of the battery, where all the connectors are.

 

[boots]

I managed to open the panel, it was very dry inside and the exit hole is very well sealed. There is a small area of white corrosion at one end, it seems fairly soft, is there something I could use to clean it off?

 

[pdarnett]

The corrosion is water damage by the look of it, even if you clean it off the component damage will still be there. For the sake of $9.90 plus shipping I'd replace it. Unless you're very good with a soldering iron and identifying dead components.