What's the Q128C like at low speeds?

I'm still trying to decide whether to go with a BBS02/01 or a Q128C for my MTB. I prefer the simplicity and clean build of a hub motor but I've read on another forum that the Q128C will bog down at low speeds or on hills (not very steep on my usual rides. Maybe 15%).

What's it like at low speeds say, 5mph?

I think the problem is that I'm trying to build for two different scenarios. 1 is when I'm towing my son with a Trail-Gator to get to the park when I won't be going very fast at all, 2 is when I'm riding on my own to get to work and I want decent speed.

When you want to go slow you use low gear and low assistance level. 15% is starting to get pretty steep, my steep test hill is 13-14%.

Having both types of motor: a 15% hill in low gear with the GSM is more comfortable than with the Mxus which requires more pedalling assistance at the same assistance level.

I can go up my 14% test hill at 15 mph with my Q128c at 48v. That's with moderate/hard pedalling and about 100kg all-up weight.

Mine's the 36v 201 rpm version at 48v, which gives speeds around the mid 20s. The 48v 201 rpm one maxes out at 19 mph, so is better suited to hauling heavy loads

anything over 12%, you are better off on a CD kit.

BBS02 then?

BBS02 then?

yes. 15% is where the BBS02 justifies itself.

yes. 15% is where the BBS02 justifies itself.

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The climb up to my home is insane!

 

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I just checked the actual incline on my route and it's only 10% so I'm probably still good to go with a Q128C. Still considering a BBS02 but it works out significantly more expensive.

A Q128c won't have any trouble with a 10% climb. It would probably beat the BBS02 at 15% too, and it's a much better motor.

There's 4 versions so you pick the one that suits your needs:

• 36V 201 rpm. It'll do about 19 mph flat out, but is quite efficient at climbing. At 48v, it gives speeds in the mid 20s, has good climbing power, but might lack the efficiency needed for long steep climbs.
  
• 48v 201 rpm is the ultimate climber. It has good torque and efficiency, but 19mph maximum, which will drop to 15 mph when the battery runs down.
  
• 36v 328 rpm. If you don't weigh too much so you can get away with less power, this one will get you into the mid 20s, but with 33% less torque than the 48v one at the same current.
  
• 48v 328 rpm. I'm not sure if this one is different to the 36v 201 rpm one. It might well be identical but I haven't tried it.
  

The Q128H has a slight bigger rotor and stator, so can handle a bit more power than the Q128C.

All these motors will run with 1000w from the battery (20 amps at 48v). I run my Q128C with only 14 amps at 48v. You'll probably find that's all the power you need. It'll do my 14% test hill without pedalling (just) with 100kg all-up weight. I also have a 201 rpm Q128H at 20 amps and 48v. It's complete overkill for what I want.

A Q128c won't have any trouble with a 10% climb. It would probably beat the BBS02 at 15% too, and it's a much better motor.

 

There's 4 versions so you pick the one that suits your needs:

 

• 36V 201 rpm. It'll do about 19 mph flat out, but is quite efficient at climbing. At 48v, it gives speeds in the mid 20s, has good climbing power, but might lack the efficiency needed for long steep climbs.
  
• 48v 201 rpm is the ultimate climber. It has good torque and efficiency, but 19mph maximum, which will drop to 15 mph when the battery runs down.
  
• 36v 328 rpm. If you don't weigh too much so you can get away with less power, this one will get you into the mid 20s, but with 33% less torque than the 48v one at the same current.
  
• 48v 328 rpm. I'm not sure if this one is different to the 36v 201 rpm one. It might well be identical but I haven't tried it.
  

The Q128H has a slight bigger rotor and stator, so can handle a bit more power than the Q128C.

 

All these motors will run with 1000w from the battery (20 amps at 48v). I run my Q128C with only 14 amps at 48v. You'll probably find that's all the power you need. It'll do my 14% test hill without pedalling (just) with 100kg all-up weight. I also have a 201 rpm Q128H at 20 amps and 48v. It's complete overkill for what I want.

Nice info. In fact, I've photographed your tabulation for future reference.

I wouldn't want to contradict d8veh because I have the 201RPM Q128H running at 48V but I would say this: don't buy a kit on its ability of climbing hills alone. As far as I know, you will have to buy the Q128C or Q128H from bmsbattery. That means from China with all the difficulty when you need to send something back there. Plus, you need to choose the right controller, battery and pedal sensor for your circumstance.

I sell hub kits, XF08C for cassette, SWX02 and BPM for freewheel. I don't think my offerings are inferior or less sensible to bmsbattery's Q128C and Q128H. I will also make sure that your conversion is a success in as little time as possible. I have a 3D printer, so I can fix problems like pedal sensors when a plastic piece would solve a fitting problem.

Edited August 25, 20178 yr by Woosh

A Q128c won't have any trouble with a 10% climb. It would probably beat the BBS02 at 15% too, and it's a much better motor.

 

There's 4 versions so you pick the one that suits your needs:

 

• 36V 201 rpm. It'll do about 19 mph flat out, but is quite efficient at climbing. At 48v, it gives speeds in the mid 20s, has good climbing power, but might lack the efficiency needed for long steep climbs.
  
• 48v 201 rpm is the ultimate climber. It has good torque and efficiency, but 19mph maximum, which will drop to 15 mph when the battery runs down.
  
• 36v 328 rpm. If you don't weigh too much so you can get away with less power, this one will get you into the mid 20s, but with 33% less torque than the 48v one at the same current.
  
• 48v 328 rpm. I'm not sure if this one is different to the 36v 201 rpm one. It might well be identical but I haven't tried it.
  

The Q128H has a slight bigger rotor and stator, so can handle a bit more power than the Q128C.

 

All these motors will run with 1000w from the battery (20 amps at 48v). I run my Q128C with only 14 amps at 48v. You'll probably find that's all the power you need. It'll do my 14% test hill without pedalling (just) with 100kg all-up weight. I also have a 201 rpm Q128H at 20 amps and 48v. It's complete overkill for what I want.

I wish they did a version about 260rpm. I am going to be trying the 260rpm version of the Q100H soon.

I wish they did a version about 260rpm. I am going to be trying the 260rpm version of the Q100H soon.

In another way you can have 260rpm approx. in a Q128. Over volt the 201/36 @ 48v you get approx. 30% more speed so it runs at 265/268rpm, or run the 48v at 36v to get a similar result but not quite as efficient.

In another way you can have 260rpm approx. in a Q128. Over volt the 201/36 @ 48v you get approx. 30% more speed so it runs at 265/268rpm, or run the 48v at 36v to get a similar result but not quite as efficient.

I've only got 36v or 44v option and was thinking given the Q128 good power a 260rpm would be powerful enough for me at 36v if they did one. I will post how my Q100H 260RPM @36v test goes when I do it.

I wouldn't want to contradict d8veh because I have the 201RPM Q128H running at 48V but I would say this: don't buy a kit on its ability of climbing hills alone. As far as I know, you will have to buy the Q128C or Q128H from bmsbattery. That means from China with all the difficulty when you need to send something back there. Plus, you need to choose the right controller, battery and pedal sensor for your circumstance.

I sell hub kits, XF08C for cassette, SWX02 and BPM for freewheel. I don't think my offerings are inferior or less sensible to bmsbattery's Q128C and Q128H. I will also make sure that your conversion is a success in as little time as possible. I have a 3D printer, so I can fix problems like pedal sensors when a plastic piece would solve a fitting problem.

Did your (woosh) new switchable kits arrive yet

I also have a 201 rpm Q128H at 20 amps and 48v. It's complete overkill for what I want.

Do you want to sell it?

Do you want to sell it?

It's on a bike. I'll sell the whole thing when I sort out some minor things on it, which I'll do when I get one of those round tuits. I have one somewhere, but I can't find it.

 

There's 4 versions so you pick the one that suits your needs:

 

• 36V 201 rpm. It'll do about 19 mph flat out, but is quite efficient at climbing. At 48v, it gives speeds in the mid 20s, has good climbing power, but might lack the efficiency needed for long steep climbs.
  
• 48v 201 rpm is the ultimate climber. It has good torque and efficiency, but 19mph maximum, which will drop to 15 mph when the battery runs down.
  
• 36v 328 rpm. If you don't weigh too much so you can get away with less power, this one will get you into the mid 20s, but with 33% less torque than the 48v one at the same current.
  
• 48v 328 rpm. I'm not sure if this one is different to the 36v 201 rpm one. It might well be identical but I haven't tried it.
  

The Q128H has a slight bigger rotor and stator, so can handle a bit more power than the Q128C.

 

I ordered a Q128H 36V 201 rpm yesterday from BMSBattery, which I plan to run mostly at 36V

If I had bought the 48V 201 rpm, what would be its performance on a 36V 14A controller?. Would its max rpm scale down to 150 rpm?

I ordered a Q128H 36V 201 rpm yesterday from BMSBattery, which I plan to run mostly at 36V

 

If I had bought the 48V 201 rpm, what would be its performance on a 36V 14A controller?. Would its max rpm scale down to 150 rpm?

Yes. It would be too slow for most people, though it would be great in the Alps.

I ordered my Q128H from BMS Battery on the 8th November and they took the money.

On the 9th November they contacted me by email to say that their order processing mechanism had under charged me; that due to the inclusion of a 26" rim in the order, they would need to charge me an extra $89. They suggested that I allow them to exclude the rim from the order. I replied to the email accepting that proposal.

When 2 days later I had no acknowledgement, and there was no change on the order status page I repeated my acceptance via a message to that page.

Now 10 days later, and I've had no acknowledgement from them; there has been no change to the status; it still shows "Waiting for sending", which it attained on the 9th November.

I've asked if I should cancel and replace the order; I asked how I should go about cancelling the order; and asked for just some acknowledgement that the order is progressing.

So, I'm £200 out of pocket and a totally unresponsive supplier. What are my options?

1) Thanks for the answer, d8veh, about the motor speeds..

2) FYI to NJS, I ordered a Q128H on 11/10.. I also got an email last monday from Wendy asking to change the order slightly. I replied OK and she acknowledged my OK with a second email. .A third email said the order had been validated. Web page says it shipped. So you might want to resend that email, rather than relying on the website,