UK compliant converter kit

paddyb

Finding my (electric) wheels
Jul 12, 2021
14
0
I’ve been looking at converting my mountain bike to a peddle assist e bike. The main reason is to help me get up a couple of hills that are just a little bit too much for me as I have a minor health condition. I think torque rather than speed is more important, though the hills are not really that great and I won’t be relying on the bike to do all the work, I will still add some peddle power.

Looking at a front wheel conversion as this sounds a lot easier to do than a mid-drive.

Main concern is about it being legal for UK use (without tax & insurance), which seems to be a bit of a minefield! I’ve read some posts on here and elsewhere and understand that it can’t be more than 250w, but more. powerful motors can be used if power/speed can be restricted?

This is the cheapest 250w I could find (£182.99)

But there is also a 500w version for £179.95

And this 500w one on Amazon is a little cheaper:

Would these kits be compliant with UK rules, or would I need to buy / do anything else?

Also, what is the cheapest battery that you recommend for these kits? Would this one suffice:

The longest journey I’m likely to do would be a 25 mile round trip (with me peddling).

Thanks in advance!
 

wheeliepete

Esteemed Pedelecer
Feb 28, 2016
2,047
757
61
Devon
Those Voilamart kits are not that great as they only offer throttle assist. The larger 500w hub motors are also best avoided unless you have £4-500 to invest in a suitable battery and want to go fast on the flat. Don't skimp on a battery, it's the most important part of the kit. There's not a lot of choice at the moment in kits as many suppliers are out stock. These kits offer good value and are shipped from the UK.
 
  • Like
Reactions: kezzer green

paddyb

Finding my (electric) wheels
Jul 12, 2021
14
0
Thanks both

I'm not bothered about speed or distance, just need a bit of extra powerfor hills. I was hoping I could do it for under £300 inc battery, that doesn't seem possible with the kits you mentioned.

What is throttle assist and what is the drawback of this vs the alternatives?
 

sjpt

Esteemed Pedelecer
Jun 8, 2018
3,832
2,756
Winchester
Why not rear wheel conversion?

Most 250w 'nominal' motors generate a lot more than that peak. The cheap motors you reference look as if they are direct drive, as opposed to those with gears in the motor. They are not very good at hill climbing, and they are pretty inefficient at most speeds so need a powerful battery (as noted above) which kills the benefit of the motor being cheap. Search these forums and you'll find lots of people disappointed with cheap direct drive motors.

I'm afraid you won't get anything satisfactory for under £300 all in unless you are very lucky. Something like https://wooshbikes.co.uk/cart/#/product/uid-264-xf07kit-g30/xf07-front-hub-kit-with-g30-105ah-battery would suit, but is around £500. You can probably get something similar with careful buying around of parts for quite a bit less than that; but still well over £300; and you'll lose out on the excellent customer service you would get from Woosh. Or the XF08 equivalent with rear drive.

Throttle assist means the motor works when you press or twist the throttle, pedal assist (PAS) works as you turn the pedals. Except for some specific situations (such as walk and slow speed assist) throttle assist is not legal for a pelelec, especially if not associated with pedal assist.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
It's worth paying a few more pounds for a decent kit. It's going to be on your bike helping you for years and thousands of miles, so worth getting one that you're going to like.

The cheap kits have bad control systems that make it difficult to get the right amount of power. Instead, they just give maximum power whenever you pedal, which isn't very convenient. Look for a kit with an LCD control panel and 5 levels of assist. The ideal kits have KT controllers. You have to learn to recognise what the KT controllers and LCDs look like to see if any kit has them.

Even the 250w kits will probably have enough power for what you want. Those 500w Voilamart kits actually give you less climbing power than the smaller 250w motors.

The kit or motor has to be labelled 250w to be legal. You can put as much power through it as you want. Some "250w" motors can give masses of power - definitely all the power you need. Kits are modular - you can change controllers and batteries to get whatever power you want. It's only the motor that has to be labelled 250w. The rest is up to you.

As an example, the Woosh 48v 17A 250w kit gives 48 x 17 = 816 amount of help when pedalling. The Cyclamatic Power Plus bike has a 12A controller and 24v battery, so gives 24 x 12 =288 amount of help, which is about 1/3 of what the Woosh kit gives. I changed a Cyclamatic's controller to 17A and the battery to 44v. It then gave 44 x 17 = 748 amount of help, which was enough to climb hills without pedalling and reach a top speed of 33 mph - legal on power, but not on speed.

The main factors that determine how well hub-motors climb are the current from the controller and the voltage, but all motors have their own maximum speed that depends on how the internal coils are wound. It's important that the motor's maximum speed at the voltage you run it is suitable for you. You want a motor with a maximum speed of anout 1.2 to 1.3 times your modal travelling speed. To make that easy, if you want to travel at 15 mph, you need a system that gives a max motor speed of around 240 to 270 rpm. Motor max speed changes in direct proportion to battery voltage, so a 200 rpm 36v motor will become 260 rpm at 48v.

Sorry if it all sound complicated. It's quite important to understand these things if you want to get a kit that matches your needs.

Nearly all kits have the ability to set the maximum speed at the legal limit, regardless of power and regardless of the motor's own maximum speed.
 
  • Agree
Reactions: sjpt

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
Thanks both

I'm not bothered about speed or distance, just need a bit of extra powerfor hills. I was hoping I could do it for under £300 inc battery, that doesn't seem possible with the kits you mentioned.

What is throttle assist and what is the drawback of this vs the alternatives?
Throttle only is now illegal. The motor's power has to be cut when you stop pedalling. £300 is too tight. A decent battery is about £250.

Where do yo live? If you're anywhere near me, I can probably help you out with some stuff.
 

paddyb

Finding my (electric) wheels
Jul 12, 2021
14
0
Thanks everyone for your replies. As expected, like anything, this is far more complicated than it seems at first! Thank god for online forums, I don't know what we did before we had them!

I'm begining to adjust in my mind the amount that I am prepared to pay, but £500 is still a little too steep. I think I will need to sacrifice something. I really only need to bit of help up hills. The usual journey will be to go fishing, which is 3.2 miles each way, with a long but slight hill (perhaps there a way I can find out the actual gradient opn google maps or something?) Luckily, I'm only 9 1/2 stone, my fishing gear is very light so probably only adds another stone.

Theres a nearly new one of these on sale locally for £400:

Only used twice apparently. If I raise my budget to £400, is this sufficient for my needs or could I get better value from £400 spend on a conversion kit (but also factoring in that I'm not very good at DIY etc).
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,899
6,507

paddyb

Finding my (electric) wheels
Jul 12, 2021
14
0
Thanks for the link. This looks like a nifty little machine for the price, but appears to be much closer to a moped than a bike (there are no peddles) and would presumably need to be taxed and insured for road use?
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,899
6,507
there not road legal but plod does not care even if the law says otherwise there are kids round here on them in gangs and plod does nothing about it.

there parents even hire the scooters for them it is a joke so if it can do what you want then buy it at a price you can afford.


id go fishing with one of those down the canal pmsl BOOM! :p
 
Last edited:

StuartsProjects

Esteemed Pedelecer
May 9, 2021
1,787
1,009
and would presumably need to be taxed and insured for road use?
Looks like it would.

And if the local Police in your area took an interest, or you had an accident, it could impact on your driving license, driving without insurance etc.
 

paddyb

Finding my (electric) wheels
Jul 12, 2021
14
0
Thanks for your feedback. I enjoyed the fishing video, but guess that is also illegal!

The Roadhog bike has been sold, but there’s one of these on sale locally for £350:
https://www.halfords.com/cycling/bikes/electric-bikes---back-in-stock/apollo-phaze-e-bike-2021-20in-445910.html

A few positive mentions (but all from the same person) on this forum. Not a great spec, esp the battery, but might just fulfill my needs. Selling for £799 in Halfords, though I’ve seen mentions of them being available for £500 in the past.

The pushbike I have at the moment is an Apollo Slant, which is a cheaper model from Halfords. Bought it second-hand and never had any problems with it.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
The Appollo is only 24v, so would be only suitable for light people or those that don't want much assist.
 

paddyb

Finding my (electric) wheels
Jul 12, 2021
14
0
Well I’m under 10 stone and even with fishing tackle probably only 11 ½ stone max. Would the Apollo be a better solution than the Voilamart kit mentioned in my original post? It has a Shengyi front motor, not sure if it’s geared or not.

Looking on eBay, most are collection only, but there are a few with delivery options:

https://www.ebay.co.uk/itm/265157330908
New, googled it but not much came up, probably rubbish.

Second-hand:
https://www.ebay.co.uk/itm/164953160986
Seems to have some good mentions on this forum

https://www.ebay.co.uk/itm/334074558990

https://www.ebay.co.uk/itm/402990345776

https://www.ebay.co.uk/itm/373643236527

All under £400, but have quite a few bids, so may well go over budget.

Any thoughts on these vs the Apollo?
 

paddyb

Finding my (electric) wheels
Jul 12, 2021
14
0
I just bit the bullet and bought this one:
https://www.ebay.co.uk/itm/164953160986

Started a new thread about it here: