The lights are on but nothing's turning...

AlexC

Just Joined
Feb 11, 2024
2
0
I have a Halfords Assist ebike that's not working... I can switch on and the lights come on, but as soon as I turn the pedals they switch off. Should I suspect the controller?

The serial number on the controller is b-wzkd2413ka-jm105-f4

I can't find the same one for sale online, but I do find various others that have similar ratings and the same connectors...

I'm new to this - any advice most welcome!
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,798
3,135
Telford
I have a Halfords Assist ebike that's not working... I can switch on and the lights come on, but as soon as I turn the pedals they switch off. Should I suspect the controller?

The serial number on the controller is b-wzkd2413ka-jm105-f4

I can't find the same one for sale online, but I do find various others that have similar ratings and the same connectors...

I'm new to this - any advice most welcome!
There could be several causes, but nothing happens for nothing. Did something happen to the bike just before it showed the problem? What were the circumstances when it stopped working?

Don't buy anything until you know the cause of the problem.
 

AlexC

Just Joined
Feb 11, 2024
2
0
Thanks for your replies. I was given the bike in the state that it's in; I don't know the history. Have replaced the sensor that sends the signal from the pedals. Battery voltage is fine. Display lights up and I can change modes (gears). As soon as I turn the pedals (ie. send a command to the control unit) the display switches off...
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,798
3,135
Telford
Thanks for your replies. I was given the bike in the state that it's in; I don't know the history. Have replaced the sensor that sends the signal from the pedals. Battery voltage is fine. Display lights up and I can change modes (gears). As soon as I turn the pedals (ie. send a command to the control unit) the display switches off...
You need to do some tests with a meter. Do you have one?
 

AndyBike

Esteemed Pedelecer
Nov 8, 2020
1,377
586
You need to do some tests with a meter. Do you have one?

Maybe all these hub drives should come with one as standard. There always seems to be a need for it.

Bag of parts inc;
Reflectors
lights(F&R)
Pedals
Voltage meter
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
1,854
1,341
When you say the lights come on, is that the front and rear bike lights, or lights on the ebike display indicating that it is switched on?

And...does the bike itself ride OK, with assistance working as it should, or is there more wrong than just the lights?

If the bike rides OK, I would not worry about the lights, just find another way to power them.
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,798
3,135
Telford
Maybe all these hub drives should come with one as standard. There always seems to be a need for it.

Bag of parts inc;
Reflectors
lights(F&R)
Pedals
Voltage meter
In case you didn't know, meters are used for checking electrical items. A crank-drive motor also works with electricity. It's a three-phase motor with hall sensors, electrically exactly the same as a hub-motor motor, but harder to test because the connectors are harder to get at. They also have battery connections, sensors and some sort of HID, like any ebike system, which can be tested just like any ebike as long as you can get to the connections and switch it on.

When you have a Bafang or TSDZ crank-motor, the testing is the same as with a hub-motor system, but when you have a Bosch, Shimano, Yamaha or similar system, there's very little to test because you're locked out by comms protocols that prevent the bike from switching on. To see what's going on, you'd need the official test equipment and software. In other words, all you can do is take your bike back to the shop and ask them to fix it, which is going to be expensive.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,917
8,533
61
West Sx RH
Andy bike always barks up the same tree and like an animal scent marks the same locations, he has tunnel vision and a distain for anything practical and cheaper as a transport option.
Hub bike advice is more often asked for because LBS have no idea or clue how to fault find an issue, so 99.% of LBS inc Halfrauds won't touch or bothe rwith such a bike because: 1. They didn't sell it and 2. it isn't a branded mid drive of the type they sell.
Any one with half a brain and a knowledge of electrical systems will know that a meter is a simple low cost tool to check electrical systems for shorts or voltage issues, even on a simple ebike more so a hub type bike one can if they know what they are doing should be able to pin point the problem.
 
  • Agree
Reactions: saneagle

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,917
8,533
61
West Sx RH
I have a Halfords Assist ebike that's not working... I can switch on and the lights come on, but as soon as I turn the pedals they switch off. Should I suspect the controller?

The serial number on the controller is b-wzkd2413ka-jm105-f4

I can't find the same one for sale online, but I do find various others that have similar ratings and the same connectors...

I'm new to this - any advice most welcome!
Your first port of call is to test the battery under load with a meter , check what occurs with the battery voltage. A knackered battery in most cases will always show voltage and charge but any undue current draw may cause the voltage to sag/collapse it is this that will define the battery as knackered if proven.

Next try to see if the bike works without switching lights on , it is possible there is wire short or another issue , which may simply be a knackered battery.

You haven't told us very much about the battery bar the age isn't known.
Tell us some figures for the voltage you are seeing !
If a 24v battery do you see 29.05v - 29.4v when fully charged ?
if a 36v battery do you see at 41.5v - 42v when fully charged ?

With an older or unknown bike one has to first rule out a battery issue before making or taking wild guesses at what may be wrong.
Typically if the system swithces on and stays on then one can at the least know that power supply is good and getting thru, the lights draw vey little power less then 1a typically, so not enough current draw to cause failure.

PAS will induce higher current draw via the controller , this will ask the battery to supply said current draw . It is at this point if the battery is knackered that the voltage will collapse under the current draw asked of it so one needs to test with a meter and watch the voltage to see what occurs.

One can test the bike temporary to rule out any system failure by connecting the ebike/eapc battery charger direct to the controller wiring , if the bike works temporay without issue then the battery is at fault.

As said just because a battery has volatage it is by no means an indicator that said battery is any good.

Unusual to occur but sometimes the voltage out put regulator in the controller can fail and this will cause the symptoms described but it is rare. I have only seen it once occur with my bikes in the last ten years and known fully charged batteries in good condition would not work until the controller with the fault was replaced.
One can't jump to any conclusion until the battery state has been ruled out as the cause.
 
Last edited: