Bike not working after battery replacement...Help please !!

[chris301up]

Right. I have owned my electric mountain bike for many years and generally it hasn't let me down. I have never been able to find out who manufactured it but can say it's very similar to a Whisper.

Anyway, when I first purchased it I had to fit a battery, so adapted a 36 volt to a rear cycle rack. All was well until recently when a couple of the cells died. I decided to purchase a double rear rack, incorporating a battery off Ebay (link below) which I fitted yesterday, but I now find that although I have power the motor just doesn't work.

I tested the output voltage at the battery with my multi-meter and I get around 41.5 volts, which I understand is acceptable, but when I operate the throttle the motor begins to start but then stops immediately. I have checked all connections and they all seem to be fine so does anyone have an idea what could be the problem ?

http://www.ebay.co.uk/itm/191942855451?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

 

[Nealh]

As it worked previously I suspect a poor connection or the battery has an issue probably uses poor quality generic China cells.

 

[chris301up]

Hi

Yes. As mentioned in my post the battery voltage is now around 41.5 volts and all connections are fine. In fact, I've just checked them all again.

The old battery voltage dropped down to around 24 volts fully charged and that's why I decided to change it. I did dismantle it and test each block of cells and found 3 of them were completely dead.

Do you think it could be the controller unit?

 

[Geebee]

Have you fully charged the battery?
When you test ride and the battery cuts out does the battery indicator show low voltage?

A faulty battery can show a healthy voltage with no load and rapidly plummet under load.

 

[chris301up]

Yes. I fully charged the battery as directed in the instructions before assembling and installing the rack etc..

I cannot 'test ride' because the motor doesn't operate. When operating the throttle the rear wheel starts to move slightly then just stops. That's it!

The battery indicator reads full at all times at the moment, even when operating the throttle.

 

[Slimjim]

Hi Chris, I have a similar issue on a Cytronex kit I was given and have fitted to a mountain bike. Motor cuts in for a second or two, then off for ten, then back on for a second etc etc. Mine is the original battery which the charge we reports is fully charged. I can't measure voltage under discharge easily to see if it drops, I'll try doing this tomorrow night and let you know if mine drops below a sensible voltage.

 

[chris301up]

Hi Slimjim

Thanks for the information. However, after spending several hours going over the wiring again, I think I may have stumbled upon the problem? It's either a faulty hall sensor or the wiring connecting to it. I will investigate further tomorrow and report my findings.

 

[Slimjim]

Hi Slimjim

Thanks for the information. However, after spending several hours going over the wiring again, I think I may have stumbled upon the problem? It's either a faulty hall sensor or the wiring connecting to it. I will investigate further tomorrow and report my findings.

Cheers Chris, I tried a new crank hall sensor tonight, with no real improvement, but hopefully neither if us is suffering battery problems.. good luck, Adam

 

[Slimjim]

Cheers Chris, I tried a new crank hall sensor tonight, with no real improvement, but hopefully neither if us is suffering battery problems.. good luck, Adam

Sorry, just read a reply to my other post, I'm guessing you mean the hall effects in the motor...? My hub only has three (power) wires to the controller, so must have electronics inside the hub.

 

[chris301up]

Just an update.

I have today gone through all the wiring and connections and have managed to get it to work - sort of ! The only way the rear wheel will work is if I place the bike on the side stand, turn the wheel slightly rearwards and then it turns and accelerates with the throttle. No way will it start on it's own and not with any weight on it.

I have done the test on the rear wheel Hall Sensors and they all give readings of between 0 volts to 4.5 volts, so assume these are working as they should. I can now only assume it's the controller at fault? But, am only guessing!

Any further advice would be good.

 

[Slimjim]

Could that be a 'dead' phase?

 

[chris301up]

What is a 'dead phase' and is there any way to test for it?

 

[Deleted member 4366]

Please provide a picture that clearly shows all the wires coming out of the controller.

 

[chris301up]

I'm sorry I cannot provide a picture of the controller as I don't have access to a camera. However, I have uploaded a picture of the same controller that/s fitted to the bike at the moment. Perhaps this will be of some help?

 

[chris301up]

Just some more information that may be of use

I have spent quite a bit time going over the connections and wiring again this evening and all seems to be fine. The only way I can get the wheel to turn is by pulling it rearwards, sometimes by a full turn, and then it will start and change speed normally using the throttle.Once I let the speed drop to zero, or use either of the brakes to stop the wheel, it will not start again unless I do the aforementioned again.

I have removed each of the motor connectors and, as expected, the speed of the rear wheel is affected accordingly. I don't think from this that there is a 'dead phase' if that is what it refers to?

I tried sitting on it and pushing it backwards slightly, whilst holding the throttle, and although the motor sounds like it wants to go, it just won't. I cannot describe it better but hope this gives you an idea of the issue?

 

[Deleted member 4366]

Does your controller have exactly the same wires?
What are the black wires for?
Are they connected or disconnected on your bike?

 

[chris301up]

Yes. That is the same controller. There are twin white/black wire which run to the brake levers. The others, which look black in the picture are grey and aren't connected to anything.

If I recall correctly the wiring consist of the following

1. Power In (Thick Red & Black)
2. Brake Lever (Black & White x 2)
3. Handlebar Displayer (Orange & Black)
4. Throttle (Blue & Black & Red)
5. PAS (Black & Red x 2)
6. Hall Sensors (Red & Black & Blue & Yellow & Green)
7. Motor (Thick Yelllow & Red & Green)
8. Unused (Grey x 2)

Hope this helps?

 

[lee-wave]

Yes. That is the same controller. There are twin white/black wire which run to the brake levers. The others, which look black in the picture are grey and aren't connected to anything.

If I recall correctly the wiring consist of the following

1. Power In (Thick Red & Black)
2. Brake Lever (Black & White x 2)
3. Handlebar Displayer (Orange & Black)
4. Throttle (Blue & Black & Red)
5. PAS (Black & Red x 2)
6. Hall Sensors (Red & Black & Blue & Yellow & Green)
7. Motor (Thick Yelllow & Red & Green)
8. Unused (Grey x 2)

Hope this helps?

This may work - after you spin the wheel by rotating the wheel backward, stop the rotation, disconnect the battery for 10 seconds or so and plug in again. It could be that the controller has to relearn the hall positions...

 

[chris301up]

Hi

Just tried that and no joy. Still the same.

 

[Alan Quay]

I'd guess it's a problem with one of the hall sensors.

You would be best to test them with a meter.

Then, I would buy new controller that will run sensorless (like the KU65 or S06P from BMS battery)