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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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Outlaw Pete

Some further thoughts on the Fiido D2S after another few days of living with it.

Biggest gripe would be that when using the highest setting, battery life only lasts for 20km and as low as 15km if using the throttle at its max. A little jerky at times with regards to power delivery too but overall I'd still recommend one as they're really fun to use and a great alternative to the stand-up scooters I think.

My nephew has pretty much nicked it off me now and so looks like I'll be getting something else that maybe better suit my needs. The D2S is excellent for whizzing about the local area or even the city to avoid the traffic but wouldn't be at all suited for rides over 15km to 20km and that's what I think I'd prefer.

The Fiido was my first foray into the world of ebikes and have to say it has for sure resulted in me being bitten by the bug. Not sure what I'll get next but it'll be have to have bigger wheels, better battery life and most likely something a little faster too.

unkel

Outlaw Pete wrote: »

it has for sure resulted in me being bitten by the bug. Not sure what I'll get next but it'll be have to have bigger wheels, better battery life and most likely something a little faster too.

Welcome to the club! I still don't know what I want next. My folding mountainbike is now provisionally sold, which leaves me with the old 26" wheel full sus specialized with the Bafang mid drive. Can't ride it at the moment as the bolt for one of the cranks fell out and not quite sure what parts to get (on line) to fix it.

Cracking bike, but with the profits I made buying, selling and fixing, and it being my hobby I feel I deserve something really nice and maybe even new that I can convert. Must be full sus, must have 29" wheels. Bottom bracket is a bit of an issue as most decent modern bikes have press fit BB, which don't suit Bafang mid drives. I'm thinking of a Vitus Mythique and converting it with a BBSHD

insular1

[Deleted User] wrote: »

See below my 3rd Ebike I made up. This was definitely my favourite, this is the MAC 8T Motor.

Below then you will see the cycle analyst which was dead handy for monitoring voltage , current and ah pulled from the pack so it was easy to know exactly what you use and what's left.

Also you will see all my LiPo, this was about 66 volts hot off the charger and allowed me about 64 Km/h, oh yes, I really loved this setup !

The Town in the background is Carlow Town. Pic was taken from Rossmore in County laois.

And the all essential torque arms, I was running about 3 Kw into this motor !

Finally bit the bullet and ordered a cheap rear hub kit. Decided if I didn't bite the bullet now I'd never save enough to do it ðŸ˜‚. Waiting for bits to arrive from all over the place. One thing though my torque arm arrived and I was skimming the thread again for info and saw your set up Mad_Lad. That torque arm you have there looks like a serious piece of metal! The one I got is fairly wimpy in comparison. Is that a custom job? Where'd you get it?

[Deleted User]

insular1 wrote: »

Finally bit the bullet and ordered a cheap rear hub kit. Decided if I didn't bite the bullet now I'd never save enough to do it ��. Waiting for bits to arrive from all over the place. One thing though my torque arm arrived and I was skimming the thread again for info and saw your set up Mad_Lad. That torque arm you have there looks like a serious piece of metal! The one I got is fairly wimpy in comparison. Is that a custom job? Where'd you get it?

Yes, a friend of mine made it. It did the job, I had one on each side. I was pulling about 3.5 Kw from the battery, some serious power there especially with a geared hub and this is a seriously important safety feature to have, last thing you want is the wheel popping out of the dropouts when you try cross a busy street with a truck coming. :eek:

Yours might do the job too especially if you're not running more than about 1 Kw, depends on the torque.

My controller was programmable so I was able to alter power to the motor.

What power will your setup be ? and what kit did you get ? motor etc.

I really miss this setup in the above pic, it was great, throttle made a huge difference on hills when my legs got tired, smooth power delivery, the Bosch bike is good but if you ease off on the peddles with tired legs so too will the power, seems a little counter-intuitive, it actually is and it's a right pain.

I lost 20 Kg on that bike in 3 months, wow, I need to get back on the bike again, haven't been on a bike properly since my 2nd Son came along.

insular1

[Deleted User] wrote: »

Yes, a friend of mine made it. It did the job, I had one on each side. I was pulling about 3.5 Kw from the battery, some serious power there especially with a geared hub and this is a seriously important safety feature to have, last thing you want is the wheel popping out of the dropouts when you try cross a busy street with a truck coming. :eek:

Yours might do the job too especially if you're not running more than about 1 Kw, depends on the torque.

My controller was programmable so I was able to alter power to the motor.

What power will your setup be ? and what kit did you get ? motor etc.

I really miss this setup in the above pic, it was great, throttle made a huge difference on hills when my legs got tired, smooth power delivery, the Bosch bike is good but if you ease off on the peddles with tired legs so too will the power, seems a little counter-intuitive, it actually is and it's a right pain.

I lost 20 Kg on that bike in 3 months, wow, I need to get back on the bike again, haven't been on a bike properly since my 2nd Son came along.

I have a cheap Chinese 48v 1kW hub motor kit on the way, hopefully any day now. Was really tempted by the Mac from em3ev but finances couldn't stretch that far and I got sick of waiting so ordered a cheap kit to cut my teeth. If all goes well I might take a leaf from Unkels book and sell it on to fund a better bike. But really I'm hoping this will allow me to commute (all private roads) at least some days by bike and I won't need a shower at work. Then can use less assistance on the way home to get a workout!

insular1

So as it's only 1kW 48v I'll probably get away with a generic torque arm?

[Deleted User]

insular1 wrote: »

I have a cheap Chinese 48v 1kW hub motor kit on the way, hopefully any day now. Was really tempted by the Mac from em3ev but finances couldn't stretch that far and I got sick of waiting so ordered a cheap kit to cut my teeth. If all goes well I might take a leaf from Unkels book and sell it on to fund a better bike. But really I'm hoping this will allow me to commute (all private roads) at least some days by bike and I won't need a shower at work. Then can use less assistance on the way home to get a workout!

So as it's only 1kW 48v I'll probably get away with a generic torque arm?

Yes you'd probably get away with a generic torque arm, chances are the supplied controller won't put out any more than about 15-20 amps, that should be fine. Depending on the battery voltage that might be 1 Kw or even less.

I was running 5.5 kw or should I say one of my first setups I was pulling 5.5 Kw from the battery into a "1kw Chinese direct drive motor"

, God knows what was going to the motor but I ripped out the stock wire and re-wired it with amazing wire, think alpha wire was the brand, it was really thin and could handle the power without even getting warm, the stock wire would have melted.

So, these motors can be clocked up big time, even inject a little oil to help disperse the heat against the motor covers better.

I didn't have a torque arm at first with this 1 Kw kit but it came with a "torque washer" it was basically a washer with a little bit that fitted into a slot on my old bicycle, this wouldn't have worked on a modern bike so I would say any torque arm should do you with that kit.

These direct drive motors are an absolute B1tch to pedal without power, this is where the geared hub really shines even compared to a Bosch or most Crank drives from what I've read, the current gen Bosch seemed to have addressed this and I think Brose, Brose are among the best motors out there from Berlin only OEM bikes though sadly.

With your kit and a 48-52 V battery I think you could get 48 Km/hr easily so make sure your brakes are up to the job, hydraulic disk brakes are essential.

I might actually be tempted to sell my Bosch bike and make another Mac Kit, this time I'd go with a 12T for much better efficiency on hills but would need 60 volts to give me decent speed, 2 Kw should do nicely a pretty modest setup compared to what I was used to back in the day.

insular1

[Deleted User] wrote: »

I was running 5.5 kw or should I say one of my first setups I was pulling 5.5 Kw from the battery into a "1kw Chinese direct drive motor" , God knows what was going to the motor but I ripped out the stock wire and re-wired it with amazing wire, think alpha wire was the brand, it was really thin and could handle the power without even getting warm, the stock wire would have melted.

This is what I'd love to be aiming for eventually. Have the knowledge to really mess around and modify these motors. First step would be a new controller with higher voltage and higher voltage battery pack?

[Deleted User] wrote: »

I didn't have a torque arm at first with this 1 Kw kit but it came with a "torque washer" it was basically a washer with a little bit that fitted into a slot on my old bicycle, this wouldn't have worked on a modern bike.

I think the kit I ordered comes with a torque washer. Could I use this as well as the torque arm?

[Deleted User] wrote: »

These direct drive motors are an absolute B1tch to pedal without power, this is where the geared hub really shines.

Yeah originally this was one of my primary specifications to have easy peddling, so the Mac was top of my list. I've also read the bbshd has pretty minimal drag. But impatience got the best of me and I just wanted to get something built for the summer!

[Deleted User] wrote: »

With your kit and a 48-52 V battery I think you could get 48 Km/hr easily so make sure your brakes are up to the job, hydraulic disk brakes are essential.

I actually got really lucky for my donor bike. Was going to use a rust bucket from the back of the shed but got worried at the idea of having a lot of power and only cheap caliper breaks. Managed to get my hands on a almost new Carrera hellcat for next to nothing and think it'll be a much better conversion. Only issue is it's a 29er which I read can be tough on the motors but for a first build on the cheap it'll have to do!

fixXxer

I've been cycling to work recently during the lockdown, borrowed an ebike for the trip as its about 7km. Mostly flat with a couple of steep enough hills, which was where I felt the benefit as the motor was only kicking in when I was struggling. I have no interest in cycling as a lifestyle choice to be honest but it was nice to try something that was more reliable than the bus and I felt pretty good afterwards. I tried i on a regular bike after and it was pretty unpleasant, I wouldn't do it again to be honest. Would ye have any recommendations for a bike for that kind of trip? Purely a Monday to Friday usage, I don't have the time or inclination to go for long cycles at the weekend or in the evenings.

unkel

Any eBike will do for that trip really. I wouldn't spend a lot of money on one. If you have an old bike lying around, convert it with a cheap kit and a cheap battery. If you want to upgrade at a later point or if you are finished with it, you can sell the bike on in working condition and you will get most of your money back, possibly all of it. Strongly growing business, eBikes. Lots of demand for them second hand.

[Deleted User]

insular1 wrote: »

This is what I'd love to be aiming for eventually. Have the knowledge to really mess around and modify these motors. First step would be a new controller with higher voltage and higher voltage battery pack?

Depends on the controller you have, if you're handy with a soldering iron you can mod the controller yourself.

I modded my 40 amp controller for around 80 amps, if I remember correctly, I applied just a bare amount of solder to the current sensor called the "shunt" and this allows more current to pass by altering the resistance. I just kept applying more solder until I got the Current I wanted.

What you need to ensure first is that the FETs inside the controller can handle the current and voltage should you require more top speed. This requires going to the manufacturers site and looking up the max current handling of the FETs and this will be the peak your system should pull, any more and you're walking home. This is where the likes of the cycle analyse helps because it measures the leak current and this is where a programmable controller also helps because you can start with a low power setup and work your way up when you're sure nothing is going to smoke.

Same with the voltage, you need to ensure the FETs can handle the voltage and this will be the max voltage hot off the charger not the nominal voltage rated on the battery. The capacitors also need to be rated for the voltage.

Good programmable controllers are Lyen controllers.

insular1 wrote: »

I think the kit I ordered comes with a torque washer. Could I use this as well as the torque arm?

I wouldn't bother one or the other should do at this level of power but I would just use the torque arm to be safe, if the axle spins in the dropouts it will break your 3 phase motor wires + the hall sensor wires and that will be a right pain in the ass to fix.

You got to make sure if using the washer that the little notch fits to where it's supposed to on the bike, I don't think modern bikes have the notch to allow the little notch or whatever they call it on the washer to fit.

insular1 wrote: »

Yeah originally this was one of my primary specifications to have easy peddling, so the Mac was top of my list. I've also read the bbshd has pretty minimal drag. But impatience got the best of me and I just wanted to get something built for the summer!

I've read where there is quite a bit of resistance when peddling a BBSHD without power, even some resistance is a no no for me. I like to pedal a lot ( or I used to I mean ) haven't been on the bike in ages. the Bosch bike I have now has too much resistance but it's all I have for now.

insular1 wrote: »

I actually got really lucky for my donor bike. Was going to use a rust bucket from the back of the shed but got worried at the idea of having a lot of power and only cheap caliper breaks. Managed to get my hands on a almost new Carrera hellcat for next to nothing and think it'll be a much better conversion. Only issue is it's a 29er which I read can be tough on the motors but for a first build on the cheap it'll have to do!

Yes a 29er will be harder on the motor especially on hills, the smaller the wheel diameter the more torque. This is why some People use 16 inch wheels and just use higher voltage to compensate for the reduced speed. The 29 inch wheel will give you a higher top speed that is if the system has the torque to allow it. Larger diameter wheel means more speed but less torque.

It's all fun to experiment. I miss it but I especially miss my old Mac kit. I will re-build.

John Hutton

My BBSO2 does have some resistance when pedalling with it turned off. It is noticable but it is not like pedalling in sand. Put it this way, if I ran out of battery when out I'd be a bit annoyed but it wouldn't ruin the trip, I'd get home or to where I'm going ok

[Deleted User]

John Hutton wrote: »

My BBSO2 does have some resistance when pedalling with it turned off. It is noticable but it is not like pedalling in sand. Put it this way, if I ran out of battery when out I'd be a bit annoyed but it wouldn't ruin the trip, I'd get home or to where I'm going ok

Yes that is a big turn off for me, I like peddle efficiency. Rock hard efficient tyres help this too but not so comfortable on crap country roads.

Pedal resistance is what will ultimately lead me back to the MAC hub whenever I change bikes again unless maybe there are some developments in Crank drive motors.

I think the designers of these motors would think pedal efficiency is the last thing people care about with these motors and for the majority they're probably correct.

insular1

Ah I'd say that would put the Mac top of my list too so. Assuming I even manage to get this first one going

.

One thing that attracted me to the mid drive was flat tyres. I use to commute for years in Dublin and could change a flat no bothers in 15 minutes, would barely be late for work, but it looks like a massive job with a hub motor. Ever have to change a flat on the rear when out on a ride mad_lad?

[Deleted User]

insular1 wrote: »

Ah I'd say that would put the Mac top of my list too so. Assuming I even manage to get this first one going .

One thing that attracted me to the mid drive was flat tyres. I use to commute for years in Dublin and could change a flat no bothers in 15 minutes, would barely be late for work, but it looks like a massive job with a hub motor. Ever have to change a flat on the rear when out on a ride mad_lad?

I used continential Eco Contact tyres, they had a very low rolling resistance and I pumped them to 110 Psi. The difference in going from normal tyres to these was massive, anyway, the real beauty was that they were puncture resistant so I never actually had a flat with these tyres nor the puncture resistance tyres on the Haibike.

But repairing a flat is harder alright with a hub and torque arms and you would need a tool kit when out and about, none of that is really a turn off for me, I always went for a long cycle well prepared but puncture resistant tyres are really great.

You can see the topeak bag on the rack of my bike in the pic above, it wasn't just battery in there, there was a lot more room in there. It was 60 odd volts 10ah LiPo so it didn't take up much room.

loughside

Here`s one for the battery experts..
Well i`ve just noticed today the battery led`s have stopped working (see pic). It`s a real pain this as my display (Bafang BBS02) is in no way accurate, i always knew when the last green led was lit it was time to recharge.
It was after a short ride, any possibility of it being a dry joint or wire came off??
I think this is a Shark case.

John Hutton

loughside wrote: »

Here`s one for the battery experts..
Well i`ve just noticed today the battery led`s have stopped working (see pic). It`s a real pain this as my display (Bafang BBS02) is in no way accurate, i always knew when the last green led was lit it was time to recharge.
It was after a short ride, any possibility of it being a dry joint or wire came off??
I think this is a Shark case.

I changed the battery indicator on my display to display the voltage rather than the percentage.

This is far more accurate, use the attached guide.

loughside

John Hutton wrote: »

I changed the battery indicator on my display to display the voltage rather than the percentage.

This is far more accurate, use the attached guide.

Thanks John, yes know what you mean, i have the 48v pack so going by that table when it gets down around the 42v mark it`s time to get it on the charger - would that be about right?

nokiatom

loughside wrote: »

Here`s one for the battery experts..
Well i`ve just noticed today the battery led`s have stopped working (see pic). It`s a real pain this as my display (Bafang BBS02) is in no way accurate, i always knew when the last green led was lit it was time to recharge.
It was after a short ride, any possibility of it being a dry joint or wire came off??
I think this is a Shark case.

I had the same problem. One wire at the leds
was loose and not connected, but that's just one possibility

unkel

Use one of the Bafang displays that shows voltage. They are accurate. Those LED indicators are useless. And 42V is far too low to be starting to charge it up again, imho. I would try and keep it between 45V and 54V

insular1

Another one for you battery experts. My battery arrived couple days ago from pswpower. Only got a chance to open it up and take a look last night. The connection wires look like the pictures below. Was expecting xt60 connector as I think this is what most of the cheap controllers use. No idea what these connections are? Will I have to solder xt60 to these or how will they work?

MB1380

I ordered a BBS02 from pswpower yesterday morning and got a PayPal invoice but no order confirmation email. Is this normal with them?

unkel

insular1 wrote: »

Another one for you battery experts. My battery arrived couple days ago from pswpower. Only got a chance to open it up and take a look last night. The connection wires look like the pictures below. Was expecting xt60 connector as I think this is what most of the cheap controllers use. No idea what these connections are? Will I have to solder xt60 to these or how will they work?

If your controller has a male XT60, then just cut those connectors off and crimp a pre made female XT60 wire and connector assembly onto them. That's what I do. I buy these from AliExpress, less than a EUR each. Some people prefer to solder on the XT60 connector.

insular1

Ah handy, thanks Unkel, I have a crimp tool. Are all the connectors crimpable? Or do I need to order specific ones? Also any idea what the existing connectors are?

MB1380 wrote: »

I ordered a BBS02 from pswpower yesterday morning and got a PayPal invoice but no order confirmation email. Is this normal with them?

I ordered through their AliExpress store as it was cheaper for some reason so I did get confirmation email. Not sure about orders direct through their website.

[Deleted User]

if using a 12S pack which would be 50.4v hot off the charger charging to 4.2 volts per cell, 12 cells then I wouldn't run it below 3.5 volts x the number of cells, so for 12S I would put it back on charge around 42 volts, that's a nice minimum and I'm talking minimum voltage including voltage sag, so on acceleration try not let it go below 42 volts for a 12S pack minimum at any time.

unkel

A premade eBike 48V battery is most likely 13S. Agree with your voltages though. 13 cells in series times your 3.5V is the 45V minimum I mentioned too.

unkel

insular1 wrote: »

Ah handy, thanks Unkel, I have a crimp tool. Are all the connectors crimpable? Or do I need to order specific ones? Also any idea what the existing connectors are?

I use these types. A male + a female pair of connectors for the princely sum of EUR0.74 including free shipping. I ain't getting my soldering iron out for that

Linky

[Deleted User]

I think the easiest connectors to use are the 30 amp Andersons. I have a crimp tool, they are a lot easier to use too and they make fantastic fuses should you create a short by accident they will Vaporise.

nokiatom

John Hutton wrote: »

I changed the battery indicator on my display to display the voltage rather than the percentage.

This is far more accurate, use the attached guide.

what type of voltage reader did you get and where? thanks

[Deleted User]

nokiatom wrote: »

what type of voltage reader did you get and where? thanks

https://www.amazon.co.uk/Precision-Analyzer-Consumption-Performance-Backlight/dp/B07M5XD4G9/ref=sr_1_12?dchild=1&keywords=power+meter&qid=1586720446&sr=8-12

I have one of these I use for my Ham Radio batteries, works well. I think you might get it cheaper too, I just pulled this up for reference.

There is also the cycle analyst but that would be a lot more expensive, you can see it on ebikes.ca.

It will show you battery capacity used in AH which is most useful, if you have a 20 Ah battery and you use 10 Ah you know you have 50% left etc.