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The eBike thread

unkel

A quick look seems that this doesn't really seem to fit in the cycling forum. So starting a thread here about all things eBike

I'll get the ball rolling. I have zero experience with eBikes. But I was going to build myself a battery anyway, for various reasons (like in bringing with me in my EV as a "petrol can")

I'm going to buy a solderless kit to make the battery (with 18650 cells I have removed from dead / old laptop batteries). This kit cah handle 20A max, and I would like the battery pack to produce 1kW constant. P=V*I so 1000W = 50V * 20A

This dictates that my battery needs to be nominal 48V (was thinking of making a 24V battery pack, but that won't be able to charge my car)

A quick browse on eBay and Amazon shows that you could buy a powerful 1000W bike conversion kit with everything needed except the battery for about GBP120 (a bit more from Amazon but peace of mind)

What to buy though, front wheel or rear wheel kit? Pros and cons? Any other advice?

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[Deleted User]

Looks like throttle, Brake, Pedelec and perhaps speed sensor but can't say for sure.

The controller looks a bit lightweight, I can't see FET's unless they are mounted underneath and bolted to the bike frame for heat dissipation, if they are not then I would strongly advise against modding for more power.

I wasn't thinking, the controller I linked to is an external controller not internal/integrated as is the case with most commercial ebikes, so it will have a lot more limits.

unkel

Yeah it's a nice integrated system, I'm not too keen in butchering it up. And as is, it is 100% road legal. I really like this bike, it's an enormous step up from my old one. Couldn't get over the feather weight of the front wheel.

But technically speaking, is it feasible enough to replace the controller with a more beefed up one (25-30A?) I'd say the 3 phase motor connection and the connection to the battery should be straight forward, but are the other bits as standard? I guess I wouldn't strictly speaking need a pedelec connector, a speed sensor or brake connection. Just a connection to a throttle (a part that I will then have to purchase separately)?

unkel

And you have to excuse me for being a total n00b here. I have cycled all my life but most of that was in the old analogue days with a fixed speed (single gear) bike with its only brake being when you hard push the pedal backwards

But you might have answers to these as well. What is this:

A bottle holder or something? If it is, is that a standard fit and what sort of bottle (Amazon) would fit it?

And this?

Seems to be connected to this on the rear wheel:

I guess a speed sensor? Again, is this a standard fit? What cheap speed display (Amazon) would fit this?

The hub motor has a big sticker with "Octopus" on it with a drawing of an octopus. Mean anything to you?

blackbox

First one is for holding a lock, the second a speedometer/computer. Third photo is the magnetic pickup for speedo.

unkel

blackbox wrote: »

the second a speedometer/computer.

Would any speedo fit it and work with it, or would I have to buy a complete new system with holder, cables, rear frame sensor and magnet?

krissovo

unkel wrote: »

Would any speedo fit it and work with it, or would I have to buy a complete new system with holder, cables, rear frame sensor and magnet?

Speedos and basic bike computers are so cheap it’s probably best to buy new, Cateye’s can even be picked up for under €15 in halfords and they will come with similar bits to show speed, average speed, calories etc.

[Deleted User]

unkel wrote: »

Yeah it's a nice integrated system, I'm not too keen in butchering it up. And as is, it is 100% road legal. I really like this bike, it's an enormous step up from my old one. Couldn't get over the feather weight of the front wheel.

But technically speaking, is it feasible enough to replace the controller with a more beefed up one (25-30A?) I'd say the 3 phase motor connection and the connection to the battery should be straight forward, but are the other bits as standard? I guess I wouldn't strictly speaking need a pedelec connector, a speed sensor or brake connection. Just a connection to a throttle (a part that I will then have to purchase separately)?

How about some pics of the motor and any markings to indicate make and model ?

Yes you can replace the controller and you can attach something like this.

https://www.ebikes.ca/product-info/cycle-analyst-3.html

You can make it a real torque sensing ebike and not a speed sensing one , torque sensing bikes are far better.

The cycle analyst can also plug directly into the controller or there is one which connects between the battery and controller so that you will get power in watts and ah used from the battery and you can also hook up a speed sensor so it becomes your speedo too.

You can use this controller,

https://www.ebikes.ca/shop/electric-bicycle-parts/controllers/c-c4825-l10.html

This cycle analyst

https://www.ebikes.ca/shop/electric-bicycle-parts/cycle-analysts/ca3-dp.html

The neat thing is that you can set speed and current limits on the cycle analyst and it even has motor temp input so it will reduce power if the motor gets too hot provided of course the motor has the temp sensor, perhaps they sell them on ebikes.ca I don't know. Em3ev can add temp sensors to his kits if he doesn't have them as standard by now.

If you got one of the controllers above you will have to reconfigure some wiring for throttle and motor.

I would advise if buying a controller to buy the matching throttle.

You can also just buy a cheap ebay controller something like this.

https://www.ebay.ie/itm/36-48V-1000W-eBike-Brushless-Motor-Speed-Controller-For-Electric-Scooter-Bike-GG/283530330709?hash=item4203b98255:g:4b0AAOSwLh5dFK4a

rated for 38 amps which could be hard on that motor so back to em3ev

I highly recommend this "fully programmable" controller.

https://em3ev.com/shop/12-fet-irfb3077-infineon-controller/

I used these and they're brilliant. Get the programming lead and make sure to get the "sensored" controller otherwise the motor might run very rough, sensorless controllers work fine with non geared motors but you need to give the motor a push to start and can be a pain on hills.

You can program current, speed, and how fast it will go in throttle switch position 1,2,3 etc.

You can also program the low voltage cut off to match the battery you have and also the current you can turn it down to 10 amps 15 30 etc so that when you get a better battery/motor you can unleash it's full power.

You can set motor phase limits etc.

I think you can also store the current config and any other config you make, I don't remember.

But I do remember the fun I had tinkering around with ebikes it's a fun hobby and I hope to build one again , they're just so much more fun than the boring Legal bikes and a great way to travel around the countryside and a great way to get out in the fresh air and exercise.

unkel

My eBike conversion kit sold already. Got a bit more back than I paid for all the bits and bobs. Another hobby that's not costing me any money so far

unkel

My new eBike was sold to me as

"Bike is in great condition. Just has problem with battery connection. Easy fix for sure .
Battery charging no problem but could off itself during pedaling"

and

"To question “what’s wrong with battery”
My answer is:
I really don’t know, I think it’s connection, as battery it self charges fully.
And sometimes after cycling 5min it just disconnects, after taking of and putting back it starts again, but just for short time again"

I draw the conclusion that the battery is probably on its last legs. Voltage drops under heavy load and the controller / BMS disconnects. The bike is less than 3 years old but has had heavy use as a daily commuter. For sure the battery has degraded and it won't charge past 40.7V. But apart from that it seems fine. In the 3 days I've had it, the controller had not cut out a single time, but today it did. And I had only cycled a few km after charging battery. I switched the bike on and off on the control panel beside the handle bar and after that I could cycle no bother again until I got home and then the battery still had 38.8V, so not a bother, still far from empty

So the issue is probably not the battery, maybe an intermittent fault in the controller or a dodgy connection somewhere?

I'd be inclined to leave it anyway unless it gets worse. If it does, it would be a good excuse to fit a more powerful controller and maybe just a throttle, connect up motor and battery and be done with it

unkel

Deleted User wrote: »

You can also just buy a cheap ebay controller something like this.

https://www.ebay.ie/itm/36-48V-1000W-eBike-Brushless-Motor-Speed-Controller-For-Electric-Scooter-Bike-GG/283530330709?hash=item4203b98255:g:4b0AAOSwLh5dFK4a

rated for 38 amps which could be hard on that motor

That looks the most appealing option to me. So can you confirm that if I connected the 3 phase wires from the controller to my motor, connected the positive and negative from the controller to my battery, and then just connected the "handle accelerator" from the controller to a throttle, this would work and I would get 40V * 38A = 1.5kW from the motor (minus about 20% efficiency losses) at max throttle?

What throttle would fit that connection? A link to one on Amazon / eBay would be great!

[Deleted User]

unkel wrote: »

That looks the most appealing option to me. So can you confirm that if I connected the 3 phase wires from the controller to my motor, connected the positive and negative from the controller to my battery, and then just connected the "handle accelerator" from the controller to a throttle, this would work and I would get 40V * 38A = 1.5kW from the motor (minus about 20% efficiency losses) at max throttle?

What throttle would fit that connection? A link to one on Amazon / eBay would be great!

I'm just looking at it again, it doesn't say it will work with geared hubs, they have higher rpm and some controllers won't work with geared hubs.

I don't know if your motor is geared or direct drive but you should hear the gear noise, youtube is where you will hear the sound of a geared motor.

That kind of power might not be good for your motor and battery.

OH and if you run higher power and the motor is sitting in regular aluminium dropouts you will need to re-enforce them, torque arms would be advisable.

unkel

Deleted User wrote: »

I'm just looking at it again, it doesn't say it will work with geared hubs, they have higher rpm and some controllers won't work with geared hubs.

I don't know if your motor is geared or direct drive but you should hear the gear noise, youtube is where you will hear the sound of a geared motor.

The bike was sold in Halfords at the lower end of the eBike scale (about GBP800) so I think it is safe to assume it has the cheaper direct drive motor

Deleted User wrote: »

That kind of power might not be good for your motor and battery.

Not so worried about the motor. Electric motors can usually take a good bit of abuse. And I believe most Chinese motors are 1kW anyway. Overclocking that by 20% to 1.2kW (80% efficient of 1.5kW, that we got by 38A controller * 40V pack). That's unlikely to cause problems

The battery pack, there I agree. It would push almost 5C through the pack

The pack that came with the bike is already degraded. Not too worried about writing it off. And I've a couple more hover board packs coming in. I could always get 4 of them in total for a 16Ah pack that would have no trouble with a 38A load (2.4C)

[Deleted User]

unkel wrote: »

The bike was sold in Halfords at the lower end of the eBike scale (about GBP800) so I think it is safe to assume it has the cheaper direct drive motor

Not so worried about the motor. Electric motors can usually take a good bit of abuse. And I believe most Chinese motors are 1kW anyway. Overclocking that by 20% to 1.2kW (80% efficient of 1.5kW, that we got by 38A controller * 40V pack). That's unlikely to cause problems

The battery pack, there I agree. It would push almost 5C through the pack
The pack that came with the bike is already degraded. Not too worried about writing it off. And I've a couple more hover board packs coming in. I could always get 4 of them in total for a 16Ah pack that would have no trouble with a 38A load (2.4C)

No, it's too small to be a direct drive motor with any decent power. So I believe it's a geared hub and they can't take the same abuse but it will be a learning experience.

A similar motor to the front hub you had I was running 5.5 Kw through, oh what a buzz !

However, I rewired the phase wires with much better quality wire, the original ones would have been toast.

unkel

It is a lot smaller than the one I had in the kit indeed. And that one weighed a ton. This whole bike (without the battery pack) weighs barely any more than a normal push bike. And unlike the kit bike, this one is very easy to cycle without the help of the motor

So you reckon it might burn out if I put 1.2kW through it for say up to 20s at a time?

There are some numbers on the motor and a drawing of an octopus, mean anything to you?

Another general question, the chain comes off a bit too easily. How to fix?

unkel

When I googled the first half of that number (SY73627) I got a video result on the top:

https://www.youtube.com/watch?v=5Ze8wvM9GU4

Could be coincidence but that motor is about the same size as mine, so mine could very well also be a geared hub motor, possibly exactly that model. At least I now know how they work and I can see how they are a lot more vulnerable, particularly with plastic gears :eek:

[Deleted User]

unkel wrote: »

When I googled the first half of that number (SY73627) I got a video result on the top:

https://www.youtube.com/watch?v=5Ze8wvM9GU4

Could be coincidence but that motor is about the same size as mine, so mine could very well also be a geared hub motor, possibly exactly that model. At least I now know how they work and I can see how they are a lot more vulnerable, particularly with plastic gears :eek:

Good detective work, yeah definitely looks like a geared hub you have judging by the size and yes, they're a lot more vulnerable.

The ones made my em3ev are different, they got much heavier duty gears and clutch.

So if you do run 1 Kw be easy on that throttle, this is where the Em3ev controllers come in, you can set the power limits and soft start which is easier on the clutch.

But buy one of the em3ev motors , say the mac 8 or 10 T and run 2 Kw through it and you will have one amazing setup.

unkel

Or just do it the cheap way with this 30A controller for €19 including shipping :eek:

Linky

And use it sensibly? No full throttle starts, only use full throttle occasionally when already at speed and don't use for more than a few seconds?

[Deleted User]

unkel wrote: »

Or just do it the cheap way with this 30A controller for €19 including shipping :eek:

Linky

And use it sensibly? No full throttle starts, only use full throttle occasionally when already at speed and don't use for more than a few seconds?

Not convinced it will work with a geared hub.

But yeah, easy on the throttle , no hammering it.

By the way, I find thumb throttles to be much better to me anyway.

unkel

Deleted User wrote: »

Not convinced it will work with a geared hub.

Oh yeah, you mentioned that. I don't understand what is different electronically between a direct drive and a geared hub, don't they both take a 3 phase AC connection and that's it?

[Deleted User]

unkel wrote: »

Oh yeah, you mentioned that. I don't understand what is different electronically between a direct drive and a geared hub, don't they both take a 3 phase AC connection and that's it?

It's to do with the timing, the geared hubs work at higher RPM and would upset the timing if not compatible.

unkel

Timing? It's not an ICE

Do you agree that both types of motors are connected to the controller only via the 3 wires (3 phase AC)? There is nothing else the controller is doing here, just feeding the motor with up to 30A at 40V

You might be mixing something else up with this?

[Deleted User]

unkel wrote: »

Timing? It's not an ICE

Do you agree that both types of motors are connected to the controller only via the 3 wires (3 phase AC)? There is nothing else the controller is doing here, just feeding the motor with up to 30A at 40V

You might be mixing something else up with this?

Here's some information on hall sensors that I can find quickly.

https://www.motioncontroltips.com/faq-what-are-hall-effect-sensors-and-what-is-their-role-in-dc-motors/#targetText=In%20order%20to%20energize%20the,known%20as%20six%2Dstep%20commutation.

unkel

That's a thread about DC motors.

Aren't we discussing 3 phase AC motors here?

[Deleted User]

unkel wrote: »

That's a thread about DC motors.

Aren't we discussing 3 phase AC motors here?

Never noticed in a rush, Doesn't matter, has the same effect.

Read this.

https://www.ijedr.org/papers/IJEDR1704162.pdf

unkel

That thread is also about DC motors?

[Deleted User]

unkel wrote: »

That thread is also about DC motors?

Doesn't matter, same thing, provides the same function ( I think ) lol

unkel

Ah ok, you mean that the controller might be looking to be connected to the hall sensor in the motor (if it has one) and if it's not there, it won't work?

I'll look at the connections on the current controller again when I get a chance. But I don't think there is a hall sensor connection going from the controller to the motor. And in none of the eBay ads I have read about cheap controllers do they mention having a connection for a hall sensor (or not). Maybe you are used to this stuff at the higher end eBikes?

Low Energy Eng

unkel wrote: »

When I googled the first half of that number (SY73627) I got a video result on the top:

https://www.youtube.com/watch?v=5Ze8wvM9GU4

Could be coincidence but that motor is about the same size as mine, so mine could very well also be a geared hub motor, possibly exactly that model. At least I now know how they work and I can see how they are a lot more vulnerable, particularly with plastic gears :eek:

I just realised a geared hub literally means 1 gear. I thought there was some internals going on that would flick between it's own various gears. I feel let down lol.
Good video nonetheless.

unkel

Deleted User wrote: »

yeah definitely looks like a geared hub you have judging by the size and yes, they're a lot more vulnerable.

Micah sends 52V to his 36V geared hub motors no probs and his motors are still alive several years later

https://www.youtube.com/watch?v=SHXQr2MPJS8

He does limit the current a bit though, through the cycle analyst that you mentioned. Nice bit of kit, but I couldn't justify the cost. I'll just stick with my EUR5 voltmeter that I can sticky tape to the frame, connected in series between my battery and my controller. And hopefully my common sense when applying the throttle

I think I'll just order the controller and throttle, cheap as chips and interesting to have a play with them, bypassing the current setup

[Deleted User]

unkel wrote: »

Micah sends 52V to his 36V geared hub motors no probs and his motors are still alive several years later

He does limit the current a bit though, through the cycle analyst that you mentioned. Nice bit of kit, but I couldn't justify the cost. I'll just stick with my EUR5 voltmeter that I can sticky tape to the frame, connected in series between my battery and my controller. And hopefully my common sense when applying the throttle

I think I'll just order the controller and throttle, cheap as chips and interesting to have a play with them, bypassing the current setup

It's the amps that kill, yanking the throttle etc. Nice gentle acceleration.