Help! 500w/750w Ebikes in the UK

Johnny Lee

Finding my (electric) wheels
Nov 11, 2020
10
5
Hi folks,

I have been using my 250w UNI MOKE ebike in London. I could’ve taken a more powerful bike but I just decided to take 250w one due to the UK e bike law. I have seen many people riding more powerful bikes around. Few of them are probably riding their bike illegally I suppose. Anyway I am thinking about upgrading my bike with a 500w motor. To ride a 500w ebike legally, what are things to be done? I do have a driving licence, of course. What else should I do? My google research says the bike needs to be registered as a moped. Should I just register it to DVLA? Is that all?
If any one has some advice for me, I would really appreciate your help.

Cheers,
 

sjpt

Esteemed Pedelecer
Jun 8, 2018
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Few of them are probably riding their bike illegally I suppose.
Almost certainly almost all of them are riding illegally (though very unlikely to be caught, or even to be prosecuted if they are caught).

You need tax (possibly), plates and insurance. Also I believe registering as a moped might not be that simple, as it won't have class certification that an off the shelf moped would usually have.
 
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vfr400

Esteemed Pedelecer
Jun 12, 2011
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It's not worth it. The system to get your bike registered is complicated, the insurance is expensive- much more than a normal motorbike. Then, when you get all that sorted, you can only ride it on the road with a motorbike helmet. It would be absolutely pointless now that you can get knocking on 200mpg from small motorbikes.

There are a lot of ways to get all the power you need legally without having to go down the registration route. The legal limit is on the rating of the motor, not the power the motor gives and many motors are extremely under-rated, so it's no problem to go much higher on power than their rating.

If you want to get more power out of your bike, there are ways to do it legally, starting with increasing the current from the controller.
 

Johnny Lee

Finding my (electric) wheels
Nov 11, 2020
10
5
You got the point!! I am glad you said all these things. That’s why didn’t want to register my bike. I rather get a motorbike. I also thought about adjusting something from the controller. I have seen a few ways on Youtube. But my controller is designed by Urbandrivestyle. I don’t think I can change the setting on the controller without their permission. How can I get more power without changing the motor?

Cheers,


It's not worth it. The system to get your bike registered is complicated, the insurance is expensive- much more than a normal motorbike. Then, when you get all that sorted, you can only ride it on the road with a motorbike helmet. It would be absolutely pointless now that you can get knocking on 200mpg from small motorbikes.

There are a lot of ways to get all the power you need legally without having to go down the registration route. The legal limit is on the rating of the motor, not the power the motor gives and many motors are extremely under-rated, so it's no problem to go much higher on power than their rating.

If you want to get more power out of your bike, there are ways to do it legally, starting with increasing the current from the controller.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
8,405
3,364
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You got the point!! I am glad you said all these things. That’s why didn’t want to register my bike. I rather get a motorbike. I also thought about adjusting something from the controller. I have seen a few ways on Youtube. But my controller is designed by Urbandrivestyle. I don’t think I can change the setting on the controller without their permission. How can I get more power without changing the motor?

Cheers,
Can you show us the controller?
 
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Johnny Lee

Finding my (electric) wheels
Nov 11, 2020
10
5
Can you show us the controller?
Considering that the Motor is from Barang and the last picture (it is from the website), I assume the controller is also from Barang. Not 100% though since my controller is just covered by the company name.

C19C921C-9D5F-427E-BEFD-58887D6F17A2.jpegF60E682E-0114-49B8-A8CE-6746D3A8E625.jpegD1072E2D-FE4F-4535-B43A-7051C5957F2F.jpeg
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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That's the LCD. The motor controller is under the battery somewhere as far as I can see. It's connected to the other end of the wire that comes out of that LCD. The LCD looks like a C961.
 
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Johnny Lee

Finding my (electric) wheels
Nov 11, 2020
10
5
Can you show us the controller?
FYI, I did try holding down the + and - to change settings
That's the LCD. The motor controller is under the battery somewhere as far as I can see. It's connected to the other end of the wire that comes out of that LCD. The LCD looks like a C961.
Sorry. I was wrong. I suppose this is the controller you meant. Thought it was a motor. I think you are right. The LCD seems a C961 like you said. (And FYI, I have tried holding down + and - to change settings but I could find the speed setting. )
 

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vfr400

Esteemed Pedelecer
Jun 12, 2011
8,405
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Basildon
Although I've never done it with one of those, I reckon that you could probably reprogram it for higher current with the Bafang programming cable, though I couldn't guarantee that it has the same firmware as other Bafangs.

The other way is to add solder to the shunt in the controller. Controllers either use a wire hoop shunt or solid state surface mount ones. The idea is to change its resistance value. The shunt is used to measure the current. The CPU sees the voltage drop across it, which is proportional to current, then allows current up to a maximum. When you reduce its resistance, the cpu thinks less current is flowing, so it allows more. You get 15 amps at the moment. For each 10% of the shunt you solder, you get 10% more current and torque from the motor.

If it's a solid state one, you have to solder one on top of it to give a value of say 30% less to get 30% more power according to the rule 1/Rold+ 1/Rnew = 1/Rtotal, where Rtotal = Rold x 0.7. The value of the old shunt is written on it. That works if there is only one shunt, but some controllers have separate shunts on each phase, which then becomes complicated.

First step would be to take the end-plate off the controller to see whether there's a wire shunt grinning at you. If not, you have to open the controller right up.
 
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Johnny Lee

Finding my (electric) wheels
Nov 11, 2020
10
5
Although I've never done it with one of those, I reckon that you could probably reprogram it for higher current with the Bafang programming cable, though I couldn't guarantee that it has the same firmware as other Bafangs.

The other way is to add solder to the shunt in the controller. Controllers either use a wire hoop shunt or solid state surface mount ones. The idea is to change its resistance value. The shunt is used to measure the current. The CPU sees the voltage drop across it, which is proportional to current, then allows current up to a maximum. When you reduce its resistance, the cpu thinks less current is flowing, so it allows more. You get 15 amps at the moment. For each 10% of the shunt you solder, you get 10% more current and torque from the motor.

If it's a solid state one, you have to solder one on top of it to give a value of say 30% less to get 30% more power according to the rule 1/Rold+ 1/Rnew = 1/Rtotal, where Rtotal = Roldx1.3. The value of the old shunt is written on it. That works if there is only one shunt, but some controllers have separate shunts on each phase, which then becomes complicated.

First step would be to take the end-plate off the controller to see whether there's a wire shunt grinning at you. If not, you have to open the controller right up.

Thank you for all these things. Now I roughly know what to do for my bike. Definitely it would be worth reprogramming. I think I can do this myself. Although I am not sure if I can manage other ways on my own, I see what you try to say. I might get some help from someone who can do this for me. I really appreciate your advice.

Best wishes,
 

Tgoldst

Finding my (electric) wheels
Mar 27, 2021
6
0
Thank you for all these things. Now I roughly know what to do for my bike. Definitely it would be worth reprogramming. I think I can do this myself. Although I am not sure if I can manage other ways on my own, I see what you try to say. I might get some help from someone who can do this for me. I really appreciate your advice.

Best wishes,
Hi

I have just picked up on this post and looking for some help with my Unimoke.
Currently it’s a 250W and I‘m looking to upgrade it to 750W and would appreciate some guidance as to the parts I require to carry out the up grade.

I’ve done the Bafang C961 changes and I’m achieving 20mph with or with using the thumb throttle.

Any help would be appreciate.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
8,405
3,364
Basildon
Hi

I have just picked up on this post and looking for some help with my Unimoke.
Currently it’s a 250W and I‘m looking to upgrade it to 750W and would appreciate some guidance as to the parts I require to carry out the up grade.

I’ve done the Bafang C961 changes and I’m achieving 20mph with or with using the thumb throttle.

Any help would be appreciate.
Is yours 36v or 48v?
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
8,405
3,364
Basildon
Hi

My rear hub is a 36v.

Thanks
Easiest way to get more power and speed is to swap the battery and controller for 48v ones, which will give a 30% increase in both. Look at your controller to see how many amps it gives and use the same for your 48v. The motor will manage that OK as long as you don't let it go too slow up steep hills for too long at full power. Help it with the pedals
 

Tgoldst

Finding my (electric) wheels
Mar 27, 2021
6
0
Hi

Mine has a 36v rear hub.

Thanks
Hi

Sorry for the double up answer.

Thanks for the info I shall have a look over the weekend.

just for info I’ve counted the teeth on my 7 speed cassette and it’s 32 on gear 1 and 11 on gear 7 with 52 on the crank.

Thanks again.
 

Tgoldst

Finding my (electric) wheels
Mar 27, 2021
6
0
36v doesn't mean anything. It's just a reference for the speed. You can run on 100v if you want. It's the current that burns the motor.
Hi

I have taken some pictures of my controller can you advise me of the best replacement process to gain more power. Thanks
 

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