Experiences with 500w geared hub motor

[simon_lipari]

Hi all. Looking into buying a kit for a friend and since I haven't tried a 500w geared hub motor kit myself I'd appreciate some advice. In theory, my friend could really use a mid drive, but she's technophobic, and even with a gear sensor to help with not destroying the drivetrain, I'm sure she would have problems with all that rear wheel torque, like when stopping to chat with someone and forgetting the power level is set to 9, and then accidentally moving the pedal! I have a 500w mid drive which is sufficient for the hills where we live, but she needs as simple a kit as possible. So, any real world advice from anyone with a geared hub motor, 500w, 36 volt, and 22 amp controller, somewhere around there? I should add that my friend weighs about 80-85 kgs, and most hills are 10-15%. Does this sound like a workable solution? At first I was checking out a 1000w 48v direct drive kit but I think it'd stroke out over here, climbing all the time, or just being really inefficient.

Appreciate your thoughts!
Simon

 

[Deleted member 4366]

The 48v 201 rpm Q128H from BMSBattery will sort her out. It's light-weight, smooth and quiet, and at 20 amps it has masses of torque. BMSB offer some batteries with the controller and rest of the kit included - 18 amps for the rack battery and 20A for the down-tube one. Both would do the job nicely.

 

[Woosh]

The 48v 201 rpm Q128H from BMSBattery will sort her out.

We have one of those kits on an 18" frame crossbar bike, 48V 11AH, ex demo, if anyone is interested.

 

[simon_lipari]

The 48v 201 rpm Q128H from BMSBattery will sort her out. It's light-weight, smooth and quiet, and at 20 amps it has masses of torque. BMSB offer some batteries with the controller and rest of the kit included - 18 amps for the rack battery and 20A for the down-tube one. Both would do the job nicely.

Thanks for the suggestion, although I'd like to order from the UK because of warranty returns etc. Had nice experiences with Woosh bikes and others. I saw this kit from Panda Bikes, Panda-500 Pro, how would that compare to the one you mentioned? Of course any similar kit sold in the UK, like the one you suggested from BMSBattery, would be great. I should add that my friend doesn't mind paying a little bit more if buying from the UK instead of ordering from Asia.

 

[Deleted member 4366]

I've no idea what there motor is. Other than it's silver, they don't give any details, except that it comes in both free-wheel and cassette versions. even if we knew what motor it is, we'd still need to know the speed because just about all motors come in different speed variants, and the speed has a massive effect on efficiency, power and torque.

 

[simon_lipari]

I've no idea what there motor is. Other than it's silver, they don't give any details, except that it comes in both free-wheel and cassette versions. even if we knew what motor it is, we'd still need to know the speed because just about all motors come in different speed variants, and the speed has a massive effect on efficiency, power and torque.

Yeah, I've asked now so I'll update when they've specified the rpm etc. Thanks again

 

[Woosh]

Simon,

I have one in black, 48V 201RPM ex demo
if you are interested, PM me.
It does not pull more than the BPM though.

 

[simon_lipari]

I've no idea what there motor is. Other than it's silver, they don't give any details, except that it comes in both free-wheel and cassette versions. even if we knew what motor it is, we'd still need to know the speed because just about all motors come in different speed variants, and the speed has a massive effect on efficiency, power and torque.

I got an email back saying the RPM of all their motors is "32kph divided by the radius of the wheel diameter of each motor size"
I forgot to mention that he said earlier that their 500w motors deliver about 40nm of torque.
I also asked if they would tell me the make etc of the motor, will update if they do. Thanks again for the help

 

[Deleted member 4366]

I got an email back saying the RPM of all their motors is "32kph divided by the radius of the wheel diameter of each motor size"
I forgot to mention that he said earlier that their 500w motors deliver about 40nm of torque.
I also asked if they would tell me the make etc of the motor, will update if they do. Thanks again for the help

That doesn't make sense at all. The motor spins at the same speed regardless of which wheel you put it in.

 

[Deleted member 4366]

Simon,

I have one in black, 48V 201RPM ex demo
if you are interested, PM me.
It does not pull more than the BPM though.

That's because it's the controller that regulates the power.

 

[Woosh]

the Q128H pulls 800W from the battery, the KT LCD displays the power.
I tested the Q128H about 30 months ago, pitching it against the SWX02 in terms of power and weight. The Q128H has a bigger reduction ratio, that attracted me to it in the first place but at the end, I went for SWX02 because the SWX02 is better finished, we have faith in Bafang for reliability and also, bigger reduction ratio would mean faster wear on ball bearings.

PS: if you are not aware of this already, the 800W is the maximum power. Compared to 1000W DD motors, this motor has about 80% of the pulling power of the 1000W but weighs half the weight of the 1000W DD motors. Where it shines is in the low speed range (<10mph) when climbing hills.

 

[Woosh]

That's because it's the controller that regulates the power.

I don't think that the Q128H will take more than 800W for long.

 

[Deleted member 4366]

I don't think that the Q128H will take more than 800W for long.

My 48v 201 rpm one will run all day with a 20 amp controller, which is 960W max.

 

[Woosh]

I don't try to denigrate the Q128H. That 48V demo bike was my favourite bike to ride around Southend for a while. If I appear to denigrate it, I certainly do not mean to say it's not worth buying. The Q128H is a smart and civilized motor. It is quiet and accelerates well and as you know, bmsbattery gave me a much better price than I pay for the Bafang motors. Suzhou Aikema offered also their version 128SX. I usually try the motor/bike on some steep bits in Southend to see how soon the motor starts to whine, the Bafang motors come out best.

This is the SWX02, slightly larger (when view from the top) and heavier than the 800W Q128H:

Here is my 800W Q128H for comparison:

 

[simon_lipari]

I

My 48v 201 rpm one will run all day with a 20 amp controller, which is 960W max.

So I'll see what Panda says about the rpm on their 500w. The controller is 22 amps max which would be 792, about the same as the q128h at 17 amps 48 volts. The Panda controller is "rated" at 11 amps. Does that mean it's not really meant for running at 20+ for too long?

 

[Deleted member 4366]

I

So I'll see what Panda says about the rpm on their 500w. The controller is 22 amps max which would be 792, about the same as the q128h at 17 amps 48 volts. The Panda controller is "rated" at 11 amps. Does that mean it's not really meant for running at 20+ for too long?

All controllers are rated at half their maximum.

This is where it gets complicated. At normal running speed, the back emf from the motor prevents the controller from giving maximum current, so you only see maximum current for short periods while hill-climbing or starting, but if you choose a motor that's too fast compared with your normal running speed, it'll be inefficient, draw maximum current for longer (can be all the time), which not only causes itself to over-heat, but also the controller.

Most controllers are located in small compartments, where they can't shed heat. If you run them out in the open air, they shed heat better, so can run much higher currents. I've run 15 amp ones, which were rated at 7 amps, at 24 amps and didn't have any problems, yet when I ran a 328 rpm q100 at 15 amps, both the controller and the motor overheated. The controller was in a compartment.

 

[KirstinS]

All controllers are rated at half their maximum.

This is where it gets complicated. At normal running speed, the back emf from the motor prevents the controller from giving maximum current, so you only see maximum current for short periods while hill-climbing or starting, but if you choose a motor that's too fast compared with your normal running speed, it'll be inefficient, draw maximum current for longer (can be all the time), which not only causes itself to over-heat, but also the controller.

Most controllers are located in small compartments, where they can't shed heat. If you run them out in the open air, they shed heat better, so can run much higher currents. I've run 15 amp ones, which were rated at 7 amps, at 24 amps and didn't have any problems, yet when I ran a 328 rpm q100 at 15 amps, both the controller and the motor overheated. The controller was in a compartment.

I have also successfully bought headtsinks off eBay and attached them all round the controller housing . Worked a treat bit of course increases the size of the controller (about double the volume in my case)

Dealt well.with some serious overvolting

 

[simon_lipari]

All controllers are rated at half their maximum.

This is where it gets complicated. At normal running speed, the back emf from the motor prevents the controller from giving maximum current, so you only see maximum current for short periods while hill-climbing or starting, but if you choose a motor that's too fast compared with your normal running speed, it'll be inefficient, draw maximum current for longer (can be all the time), which not only causes itself to over-heat, but also the controller.

Most controllers are located in small compartments, where they can't shed heat. If you run them out in the open air, they shed heat better, so can run much higher currents. I've run 15 amp ones, which were rated at 7 amps, at 24 amps and didn't have any problems, yet when I ran a 328 rpm q100 at 15 amps, both the controller and the motor overheated. The controller was in a compartment.

Thanks for explaining. Still waiting for reply about the Panda motor, RPM etc. Will update.

 

[simon_lipari]

So I got a reply about the RPM, and it's 148. Waiting for a reply about the reduction ratio.

 

[danielrlee]

I have also successfully bought headtsinks off eBay and attached them all round the controller housing . Worked a treat bit of course increases the size of the controller (about double the volume in my case)

Dealt well.with some serious overvolting

Although i imagine this approach did work, it seems somewhat daft. If you doubled the volume of the controller, you might as well just have upgraded to a larger controller to begin with, i.e. from a 6-fet to 12-fet.