Newcomer with plans!

[Shakes]

Hello All,

Having purchased what I believe to be a rare bike in the UK, I would like to upgrade the speed on my CityBlitz CB020 currently operating at 36V 350W.

As a car mechanic, I have a fairly good grasp on general electrics and cable running but I have no idea on where to start to gather some parts for this.

I was planning on a dual motor set up with 48V 500W hubs with a 48V controller. Most 72V hub systems that I have seen seem far too large for the 12inch wheels so I thought I could perhaps overwork a 500W hub for more output? Would this be possible with my current set up? Would I need to upgrade my battery? Can I upgrade to a 72V battery to help for the power flow?

Any help appreciated.
Thank you for welcoming me.

 

[Scruffydroid]

Welcome.

If you execute your plan, you will have a "Death Wish".

Please start an upgrade thread with progress, it will be an interesting one to follow.

 

[StuartsProjects]

Where do the pedals go ?

 

[Shakes]

Welcome.

If you execute your plan, you will have a "Death Wish".

Please start an upgrade thread with progress, it will be an interesting one to follow.

I shall most definitely be starting a thread to explore the different avenues for which this bike can be maxed out. Thank you for your reply!

 

[Shakes]

Where do the pedals go ?

There are no pedals nor chain system, only static BMX style pegs.

 

[flecc]

There are no pedals nor chain system, only static BMX style pegs.

Welcome to the forum Shakes. We are largely a legal pedelecs forum so best start your thread in the Speed Pedelecs forum which includes provision for proposals like yours.
.

 

[Shakes]

Welcome to the forum Shakes. We are largely a legal pedelecs forum so best start your thread in the Speed Pedelecs forum which includes provision for proposals like yours.
.

My apologies for not realising this was illegal as standard - intended for off road use once speed and power are beyond current limits.

 

[sjpt]

My apologies for not realising this was illegal as standard - intended for off road use once speed and power are beyond current limits.

Yes, I'm afraid the lack of pedals and the 350w motor make it illegal on road even as standard (unless registered and insured as a motor bike). It is also illegal off road except on private land (with landowner's permission) not accessible to the public; eg not on bike paths, bridleways etc.

Still an interesting project; which is why there is that Speed Pedelecs subforum mentioned above.

 

[Shakes]

Yes, I'm afraid the lack of pedals and the 350w motor make it illegal on road even as standard (unless registered and insured as a motor bike). It is also illegal off road except on private land (with landowner's permission) not accessible to the public; eg not on bike paths, bridleways etc.

Still an interesting project; which is why there is that Speed Pedelecs subforum mentioned above.

Thank you for clarifying - I shall consider getting it on the DVLA register with Q plates if I can achieve a nice breezy speed on it!
Gotcha with the law, no open parks either I take it.
I shall definitely be making a project post in the speed subforum to discuss these plans further.

 

[vfr400]

Nice dream, but you have very little chance of realising it.

Let's look at two motors first. A rear 500w one in a 12" rim would wheelie a short wheelbase bike like that, so a front one would get zero useful power on the road. A 500w front motor on its own in a 26" wheel stuggles for grip without a rear one unloading it. For two motors, you need two controllers and two batteries unless you can find a single obattery capable of delivering 44A continuously.

Your present battery is 180wh and capable of delivering about 15A. 15A (540w) gets you about 12 mph unless you're light, so your maximum range would be about 12 x 180/540 = 4 miles. With two 500w motors running at 22 amps, your range would be about a mile if your battery could supply that much current, but it can't.

Next problem is how you're going to get a 500w motor into a 12 " rim. There would only be about 1" gap between the motor and rim, which would make building it pretty tricky.

What can you do then? Without major engineering, a 48v battery and 17A controller, would get your present motor up to about 20 mph, assuming that it maxes out at 15 mph now. All you need to do is figure out how to install them and wire them up.

 

[vfr400]

I shall consider getting it on the DVLA register with Q plates if I can achieve a nice breezy speed on it!

Not much chance of that either, and even if you could, who's going to insure it?

It would be much cheaper, easier and safer to buy a ready made and registered electric scooter, if that's what you want.

 

[StuartsProjects]

Gotcha with the law, no open parks either I take it.

Private land only as I recall, with the permission of the land owner.

Just yesterday a pair of eScooter 'drivers' in Liverpool lost thier driving licenses for offences commited on thier eScooters, so your license could be at risk.

Is a driving license important for your job ?

 

[Nealh]

Private land only as I recall, with the permission of the land owner.

Just yesterday a pair of eScooter 'drivers' in Liverpool lost thier driving licenses for offences commited on thier eScooters, so your license could be at risk.

Is a driving license important for your job ?

Good to here some forces/courts are acting on the nuisance.
Now having lost their licence's they will probably be more of a nuisance by using these toys all the time now, having lost it once they can't lose it again except for a longer duration.

 

[sjpt]

Just yesterday a pair of eScooter 'drivers' in Liverpool lost thier driving licenses for offences commited on thier eScooters, so your license could be at risk.

Interesting.

Liverpool: Erratic e-scooter riders banned from driving

Police say two men, who were zigzagging the scooters on a Liverpool road, also failed breath tests.

www.bbc.co.uk

Drink driving e scooter riders disqualified after 'erratic' use

The two men were seen 'zig zagging' across Smithdown Road on the council-piloted Voi scooters

www.liverpoolecho.co.uk

I think that is one of the first times (even the very first) I've seen the various regulations actually followed through to sentence. I'm sure the fact they were drunk and riding irresponsibly led to the police looking into all the technical offences. Still no evidence of action being taken for responsibly ridden 'slightly illegal' ebikes; or even somewhat irresponsible riding of 'slightly more illegal' ebikes.

... p.s.
But come to think of it these were not illegal, even though the same scooters would have been illegal if privately owned. I don't know what the insurance situation is if you hire one of these. I'm surprised to see they don't have number plates on the front. I don't know how the legal exceptions are arranged for the various scooter trails, but I can't see a reason for an exception on carrying a number plate. I can't really see in the image if they do have very discrete plates on the back.

 

[vfr400]

Interesting.

Liverpool: Erratic e-scooter riders banned from driving

Police say two men, who were zigzagging the scooters on a Liverpool road, also failed breath tests.

www.bbc.co.uk

Drink driving e scooter riders disqualified after 'erratic' use

The two men were seen 'zig zagging' across Smithdown Road on the council-piloted Voi scooters

www.liverpoolecho.co.uk

I think that is one of the first times (even the very first) I've seen the various regulations actually followed through to sentence. I'm sure the fact they were drunk and riding irresponsibly led to the police looking into all the technical offences. Still no evidence of action being taken for responsibly ridden 'slightly illegal' ebikes; or even somewhat irresponsible riding of 'slightly more illegal' ebikes.

... p.s.
But come to think of it these were not illegal, even though the same scooters would have been illegal if privately owned. I don't know what the insurance situation is if you hire one of these. I'm surprised to see they don't have number plates on the front. I don't know how the legal exceptions are arranged for the various scooter trails, but I can't see a reason for an exception on carrying a number plate. I can't really see in the image if they do have very discrete plates on the back.

They were on legal for hire scooters, so not relevant. They were done for drunk driving, not riding illegal vehicles.

 

[Nealh]

I believe the trial scooter fee comes has insurance included .

 

[flecc]

But come to think of it these were not illegal, even though the same scooters would have been illegal if privately owned. I don't know what the insurance situation is if you hire one of these. I'm surprised to see they don't have number plates on the front. I don't know how the legal exceptions are arranged for the various scooter trails, but I can't see a reason for an exception on carrying a number plate. I can't really see in the image if they do have very discrete plates on the back.

They cannot have front number plates since these were abolished by law for two wheelers some sixty years ago on safety grounds. They can only theoretically carry rear number plates but don't have to for the trial.

The trial only came about as a shabby political deal because our new prime minister wants a US trade deal and accordingly gave in to US commercial requests for these scooters to be legalised in the UK.

Laughably they are excused the legalities on the grounds that they are something like pedelecs, though of course they aren't remotely like them nor fit the reasons why pedelecs are exempted from motor vehicle law.

Heaven help us if they are eventually legalised after the trial, since it could be a back door to pedelecs losing some of their current exemptions.
.

 

[Shakes]

Nice dream, but you have very little chance of realising it.

Let's look at two motors first. A rear 500w one in a 12" rim would wheelie a short wheelbase bike like that, so a front one would get zero useful power on the road. A 500w front motor on its own in a 26" wheel stuggles for grip without a rear one unloading it. For two motors, you need two controllers and two batteries unless you can find a single obattery capable of delivering 44A continuously.

Your present battery is 180wh and capable of delivering about 15A. 15A (540w) gets you about 12 mph unless you're light, so your maximum range would be about 12 x 180/540 = 4 miles. With two 500w motors running at 22 amps, your range would be about a mile if your battery could supply that much current, but it can't.

Next problem is how you're going to get a 500w motor into a 12 " rim. There would only be about 1" gap between the motor and rim, which would make building it pretty tricky.

What can you do then? Without major engineering, a 48v battery and 17A controller, would get your present motor up to about 20 mph, assuming that it maxes out at 15 mph now. All you need to do is figure out how to install them and wire them up.

Thank you for your very detailed reply with figures and values. As a man of maths and physics, they are very much appreciated. I’d like to start off with the fact that I know rather little about this topic and please do correct me if I am wrong in what I say further.

My original dream project idea would have been as mentioned above but I did not intend it to be easy to achieve or even possible - it was a starting point for me to begin to understand how I'd like them to work and what they could do.

Barring practical ideas of wheel spin (effects could arguably be reduced talking strictly from throttle control response perspective), in the event I am able to fit a 500W motor into the rim, would I be able to do a parallel connection to the other motor from the one controller in order to receive the same current and voltage across both hubs? I understand there will be 1/R resistance issues but will that be an impedance in what I am hoping to achieve?

I can also understand that the present battery most certainly will not be capable of doing what I would like for it to do, especially whilst maintaining an acceptable range - I am prioritising power in this current case scenario as I don't rely on the bike to take me certain distances, more for a fun leisure project. Would it be easier for me to purchase a ready-made battery supplying a good amount of WH // AH or build my own one out of 18650s?

 

[vfr400]

Barring practical ideas of wheel spin (effects could arguably be reduced talking strictly from throttle control response perspective), in the event I am able to fit a 500W motor into the rim, would I be able to do a parallel connection to the other motor from the one controller in order to receive the same current and voltage across both hubs? I understand there will be 1/R resistance issues but will that be an impedance in what I am hoping to achieve?

You can't run two motors from one controller because the pulses have to be exactly timed to the position of the motor. You can run two controllers from one throttle.

You would have trouble with traction from a single 250w front motor because of the high torque from the small wheel. What you need to understand is that any torque on a rear motor would reduce the weight on the front, which would reduce traction to an unacceptable level. I've built several double motor bicycles. Two 250w motors is just about acceptable. That's on 26" wheels. With 12" wheels, you'd have more than double the torque to deal with.