Hi again everyone.Last week i bought a very rough folding ebike off an old couple from sleaford on ebay.It came with a charger saying its a 24v 1.6 amp.I plug this in and i get a volt reading from it saying 39.5v.The couple told me there daughter borrowed it for work and basically ruined it so they had fitted another controller to try and revive it but the battery is no good so never got it running again.There is a couple of stickers on the frame,one says Cambridge electric motion and the other says Pack a bike.After stripping it i found it originally had a pedal assist crank motor which has been disconnected and the wires chopped off,it now has a rear wheel drive fitted by someone.So my problem is..how do i know what voltage the wheel motor is and also the battery.We all know a guessing game with batteries can either destroy half the electrics or your bank account.I have enclosed a pic of the bike,charger and battery which has 20 cells,dont know what type they are.If anyone can help or even identify what bike it is,it will be realy appreciated and thanks
Can anyone tell me the voltage
- Thread starter Winston
- Start date
Motors don't have a voltage. You can run it at whatever you want. The voltage only affects the max speed. That bike is generic. I've seen a few on this forum over the years under different brands and slightly different versions. The thing in the bottom bracket is probably the motor controller, though I've seen one where it had an external controller and there were just connectors in there. All that stuff around the crank is bespoke and irreparable, so I'm not surprised that someone has changed something.
That's the original motor in the back wheel.
All those motors work the same. What you need to get it going is a throttle, a motor controller and a battery. I'd use 36v. You can buy 36v lithium cell-packs on Aliexpress, which might slot into the battery case you have. There's no point in refurbishing it with the original cell type because it will be expensive and pretty useless. You can use any 36v battery you want if you stick it in the box on the rack. Expect to pay about £150 for the battery, £15 for the controller and £5 for the throttle. It won't be easy to fit a pedal sensor.
What's in the box? has someone already done what i suggested. I can see wires going to it. I'm going to guess that someone put a couple of 12v SLA batteries in there to run it.
if you want to proceed, show, what motor wires and connector you have so that we can advise the correct type of controller.
That's the original motor in the back wheel.
All those motors work the same. What you need to get it going is a throttle, a motor controller and a battery. I'd use 36v. You can buy 36v lithium cell-packs on Aliexpress, which might slot into the battery case you have. There's no point in refurbishing it with the original cell type because it will be expensive and pretty useless. You can use any 36v battery you want if you stick it in the box on the rack. Expect to pay about £150 for the battery, £15 for the controller and £5 for the throttle. It won't be easy to fit a pedal sensor.
What's in the box? has someone already done what i suggested. I can see wires going to it. I'm going to guess that someone put a couple of 12v SLA batteries in there to run it.
if you want to proceed, show, what motor wires and connector you have so that we can advise the correct type of controller.
I removed the screw on cover and this is what is behind it in the pic,the controller was there,its the one here in the pic and the internals of the battery have these in there>the wiring in the frame box is where its been extended to go up to the rack were they had mounted the controller but as you can see in pic i need a 3 way connector for the throttle.I never knew you can run these motors at what ever voltage you want basically, thank you so much for that info as i have one of them 24v motor kits that bolt to the frame and are chain driven,i can now put a 36v battery and controller setup on that
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That looks like a brushed motor controller, but you didn't show the motor wires, so I'm not absolutely sure. My comments above are in relation to a brushless one. It's still possible to run a brushed 24v motor at 36v, but i don't really have any experience of that.
The battery is older school stuff Ni-mh each cell is 1.2v nominal so X 20 gives you 24v, each cell has a max voltage of 1.4 - 1.6v each so about 30 - 32v for 24v, though 30v is more likely.
If someone has charged them using another charger greater then 24v then they will be toast 39v is far too high for the cells.
Best off replacing battery and controller with new.
If it is a brushed motor then we can show you a 24v/36v controller with PAS & throttle connections you can use.
The 24v brushed motor on my Swizzbee has been ran at up to 33v with no issue (not by me but another user in Switzerland) as that is about the max the controller can take, so 36v with a correct controller/battery combo should be ok. Your controller is 24v/28a rated using a 36v/19- 21a controller should be ok as the output will be not far off each other.
If someone has charged them using another charger greater then 24v then they will be toast 39v is far too high for the cells.
Best off replacing battery and controller with new.
If it is a brushed motor then we can show you a 24v/36v controller with PAS & throttle connections you can use.
The 24v brushed motor on my Swizzbee has been ran at up to 33v with no issue (not by me but another user in Switzerland) as that is about the max the controller can take, so 36v with a correct controller/battery combo should be ok. Your controller is 24v/28a rated using a 36v/19- 21a controller should be ok as the output will be not far off each other.
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I don't think it's worth fitting a PAS. Firstly, the bike has a weird BB, so fitting one won't be easy. Secondly, those controllers only give full power when you pedal, which is not really much use. it should be OK with just a throttle, which opens up more possibilities for controllers. that's assuming a brushed motor, which has yet to be confirmed, though that 28 amp controller doesn't make it very likely.
While I think about it, that controller is not likely the original. It might be too much for the motor. i would have thought that 15 to 20 amps would be more like it. Any more would make a lithium battery struggle.
We need to see a pic of the hub motor wire at the connector end.
24V brushed motors use higher current then 36v ones, my 24v Swizzbee sees a pretty much constant 16a draw and at times more then 30a.
24V brushed motors use higher current then 36v ones, my 24v Swizzbee sees a pretty much constant 16a draw and at times more then 30a.
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