Electric handbike

Hashek

1 mW
Joined
Aug 16, 2015
Messages
15
Location
Slovenia, Europe
Hello everybody,

my friend quadriplegic owns handbike attachment for his wheelchair, I think it is some older version of this thing...(it attaches on his everyday wheelchair)
Speedy-duo2.jpg
It has strange uncommon electric motor and lead batteries...i think they are 24V. It has 7 gears but are not visible (probably hidden under that big disc). It can run with throttle only or with some kind of PAS. Front wheel is 20 inch.
Here are two pics of it (sorry for bad quality)
1.jpg2.jpg

Batteries died and now he is looking for some options to update his handbike.
He is looking for about 25 kph top speed and he will not climb long steep hills just short modest climbs. Total weight of him + wheelchair + handbike is about 125 kg. He will mostly be ridding on PAS but would like to have option to simply switch to throttle only (is this possible?). We need to solve gears too...it has 135mm dropouts.

Battery:
He likes a battery from BMSB 36V 14.5Ah with integrated 18A controller with a rack (it also adds some weight on front wheel)
https://bmsbattery.com/ebike-battery/766-36v145ah-case-02-panasonic-battery-pack-battery.html

Motor: which motor would be most suitable? For 25 kph in 20 inch wheel we need about 260-270 rpm, right?
- Q100H 260 rpm with 7 speed freewhell
- Q128C 201 rpm(I read here it is actually 260 rpm...can anybody confirm this?) with 8 speed cassette
- Q128C 328 rpm (top speed of around 30 kph can be a little dangerous for quadriplegic in a wheelchair)
- Bafang CST 36V 350W 270 rpm with 8 speed cassette

We like Q128C the most but would really like to have 260 rpm.
What do you guys think?
Thanks
 
If he isn't tackling big hills I think the Q100h would be a good choice. Get the sine wave controller to go with it and you will be amazed at how smooth and quiet it is.
Contact BMSB about compatibility and specify that you want throttle control.
Their shipping is sky high so think about what spares or parts for another project you might need and order all at once.
 
Why not keep the current motor (not broken or worn out?) and just get 36V controller and battery to run the motor a little faster?
 
It can be as easy as going to Home Depot and buying a 36V battery used with mowers and trimmers, or you can order an ebike battery from Justin at www.ebikes.ca

If 25kph was his previous speed on 24V, then you'd buy 24V battery. But if he wasnt going that fast previously, then go with a 36V battery pack, and keep the same controller.

Seems to me that you'd want new. More money that way. Whats wrong with the current setup? Just dead battery, or dead battery AND not enough speed.
 
Hwy89 said:
If he isn't tackling big hills I think the Q100h would be a good choice. Get the sine wave controller to go with it and you will be amazed at how smooth and quiet it is.
Contact BMSB about compatibility and specify that you want throttle control.
Their shipping is sky high so think about what spares or parts for another project you might need and order all at once.
As i understand case 02 has built in 18A sine wave controller that should work just fine with Q100h or Q128C right?
BMSB costumer suport really do not know much about how thing work, they just know what they have on stock...that is why i am counting on you guys here that really know everything about ebike...thanks again

SlowCo said:
Why not keep the current motor (not broken or worn out?) and just get 36V controller and battery to run the motor a little faster?
markz said:
It can be as easy as going to Home Depot and buying a 36V battery used with mowers and trimmers, or you can order an ebike battery from Justin at www.ebikes.ca

If 25kph was his previous speed on 24V, then you'd buy 24V battery. But if he wasnt going that fast previously, then go with a 36V battery pack, and keep the same controller.

Seems to me that you'd want new. More money that way. Whats wrong with the current setup? Just dead battery, or dead battery AND not enough speed.

Hmmm, yes we could try new 36V battery with an old motor and see how it works...old batteries were 24V and he had problems going even 15 kph so 36V with 18A should increase speed to about 20 kph i think. He wants to ride 20-25 kph.

but just in case... we will order a new motor too, it will look "cleaner", it is smaller, lighter, faster, probably more eficient...and shipping is the same with or without motor so it is cheaper to order all together rather than just the motor later...
We really do not know anything about old motor (rpm, gears, sensors) and old controller (amperage, square, sine) just another reason to buy whole kit.
We will surely try new battery with old motor and if it works fine...great even simpler solution and we can still change motor later if needed.
 
fechter said:
How would you operate a throttle?

He is quadriplegic so he has very limited hand control and nearly no finger control. He can not push thumb throttle with his finger so he kinda pushes thumb throttle with his hand (thumb throttle is on a special lever). He operates brake and gear shifter the same way. These controls will stay as they are because this way suits him best.
4.jpg3.jpg
 
Reading your comments and looking at his handbike I wonder if it wouldn't be safer to use a DD (direct drive gearless) motor combined with a programmable sinewave controller so you can programm regenerative braking and are flexible with a lot more parameters?
I myself have a pure manual handbike and a friend of mine has an electric handbike without rotating crank/pedals. His handbike also uses a Q100 type motor on 36V and gets to about 18km/h. Although it is a low rpm motor he still complains about a lack of torque.

So my ideal electric assisted handbike would be a DD 9C motor in a wide 20" rim with a programmable sinewave controller with adjustable regenerative braking and using PAS as well as a throttle. Then also add a decent V-brake on the rim or a disk on the motor to have double braking capacity as you only have one braked front wheel...

This motor laced in 20" (preferably wide) rim:
https://bmsbattery.com/ebike-kit/554-q11-36v1kw-rear-driving-disc-brake-hub-motor-ebike-kit.html

With this controller:
https://endless-sphere.com/forums/viewtopic.php?f=31&t=81020

And a decent Amp discharge battery for long range and start up torque that you can mount under the rack above the wheel for more downforce (=mechanical grip):
https://bmsbattery.com/ebike-batter...battery-heat-shrink-battery-pack-battery.html
 
Thanks for your idea SlowCo, u got me thinking now...

Ok, big and heavy motor is strong and fast enough (maybe too strong and too fast for our needs), we can use regenerative braking (which is great safetywise), it adds weight to the front wheel (which is always needed with handbike) and with programmable controller we have more options...

I don't know...i really like those small light geared motors. I think it will be good enought for this low power setup. Plus my friend often uses handbike without assist, just freewheel - i think he wouldn't want to loose that.
Ok weight on the front wheel can be a problem but we can still add couple kg weight on a front rack...
Regen braking is not possible with geared motors but we plan to add disc brake so he will have two brakes (safety wise).
 
If he needs to be able to use the handbike manually without motor assist then you should choose the Q128 geared hub motor. The Q128H is the version for a freewheel gearset and the Q128C for a cassette.
 
SlowCo said:
If he needs to be able to use the handbike manually without motor assist then you should choose the Q128 geared hub motor. The Q128H is the version for a freewheel gearset and the Q128C for a cassette.

Yes, Q128C is my favourite too. But it only comes in 201rpm and 328rpm. Sweet spot for our setup would be 260rpm.

In one thread @d8veh even mentioned that 201rpm version is actually 260rpm....hope he or anyone else can confirm this (bmsb says they only have 201 and 328rpm).
I read in another thread that 48V q128C 328rpm powered at 36V should become 260rpm...it makes sense but i would like to be certain before i make the order. Battery will be 36V 14.5Ah with 18A controller...

Ok, our "safe bet" is still Q100H with 260rpm (which is actual 260 rpm)
 
...found it...

d8veh said:
Just to add a bit to the above, the 201 rpm Q100s and Q128H are actually around 201 rpm but the 201 rpm Q128C is 260 rpm - or at least it has been for all those that have bought one so far. On the road speeds with a 26"wheel are:
201 rpm = 15 mph (19mph with a Q128H and fully charged battery)
260 rpm = 20 mph
328 rpm =24 mph

Add 7% for a 700C wheel.

Speeds in 20 inch wheel would be:
201 rpm = 20 kph
260 rpm = 25 kph
328 rpm =29 kph
 
Ok i spent a weekend reading hundreds of posts on the forum...really impressive amount of knowledge here.

I think two guys posted about 201rpm Q128C being actual 260rpm, d8veh and one other guy...
Few guys posted their setups that could be calculated back to 201 rpm...
BMSB do not know what i am talking about or they do not answer emails...

Looks like we will have to go with Q100H just because we would not be certain about q128C rpm until we could test it ourselves.

Should i open a new thread where users with q128C/H motors can share their setups and speeds so that we all can get some info what are real rpm of this great motors? What do you think?
 
I would go with the 36V 201rpm Q128C and run it at 48V (=268rpm). That way you have a motor that can handle more power without overheating.
 
Ok, he decided to go with Q128C motor.
So we have two options:

1. Q128C 48V 328rpm version powered with 36V battery....that should give 260rpm (perfect for us).
Is this correct? Powering 48V Q128C with 36V battery will cut rpms to 260 and lower torque? Will this affect the motor in any other way?

2. Q128C 36V 201rpm version with 36V battery (little slow and we do not know if it is really 201 rpm or is it really 260rpm)

What do you think about option 1?
 
I think you're right and that option 1 is indeed the best. Although I personally would still get a 48V battery with that motor. Then even with voltage sag and going uphill you can still reach 25km/h and above. And you don't have to go faster than you like but you can if the road and circumstances are okay and you feel like it. When the systems voltage and motor rpm dictate a max speed that is lower than you would sometimes like to ride, it starts to be annoying. When you always have some extra speed left you can sometimes use it when you want to. In my best handbike days I was regularly riding around 30km/h purely manual.
And where I live a mobility vehicle (incl. electric handbikes) may have a max speed of 45k/h legally. So aiming for a max of 25km/h seems too low to me.
 
I think the Q100 is a bit small for operation by the throttle alone. It'll work, but I think the Q128C will be able to handle the torque much better. The Bafang CST would also be good, but I'd get the 500w version if you can because it's the same size and weight as the 350w one, but it can handle a lot more current if you find that 18 amps is not enough.

I think 18 amps at 36v in a 20" wheel should be able to give enough torque, but 22A would give you a bit of headroom.
 
SlowCo said:
I think you're right and that option 1 is indeed the best. Although I personally would still get a 48V battery with that motor. Then even with voltage sag and going uphill you can still reach 25km/h and above. And you don't have to go faster than you like but you can if the road and circumstances are okay and you feel like it. When the systems voltage and motor rpm dictate a max speed that is lower than you would sometimes like to ride, it starts to be annoying. When you always have some extra speed left you can sometimes use it when you want to. In my best handbike days I was regularly riding around 30km/h purely manual.
And where I live a mobility vehicle (incl. electric handbikes) may have a max speed of 45k/h legally. So aiming for a max of 25km/h seems too low to me.

Thank you SlowCo for first hand experience...

I really do not want him to go faster than 25 kph. Remember he is quadriplegic and his hand reactions (braking in mind) are slow.
If he would have a "machine" capable of 50kph he would probably use it full throtle - you know how it is, you have to try :) ...do not want to know how that would end.
No really, we both think that 25 kph top speed is just fine and safe
 
d8veh said:
I think the Q100 is a bit small for operation by the throttle alone. It'll work, but I think the Q128C will be able to handle the torque much better. The Bafang CST would also be good, but I'd get the 500w version if you can because it's the same size and weight as the 350w one, but it can handle a lot more current if you find that 18 amps is not enough.

I think 18 amps at 36v in a 20" wheel should be able to give enough torque, but 22A would give you a bit of headroom.

Thank you d8veh for your opinion...

Ok, we will go with 48V Q128C 328rpm and run it on 36V battery to get 260rpm...
 
Great. I hope you'll update this thread with photo's of the conversion so other people Googling might find this thread and learn from it. And I love builds like this so I'll be following also.
Good luck!
 
Back
Top