Where to get 20", 200-250w front hub motors?

[bdteakle]

I'm trying to get 200 w to 250w front hub motors for 20" wheels, for road-legal (more or less...) bikes I've been making. After making quite a few successful bikes my usual sources seem to have dried up.

I really prefer the Bafang/8Fun motors. Really good quality units.

I used to be able to get Bafang/8Fun motors for any size rim from BMSBattery, but they seem to be out of stock of most sizes currently and have been for months. They don't usually even have Bafang 26" rear motors in stock. BMSBattery have been flogging the Cute/Ananada Q-series motors for the last couple of years but don't seem to stock 20" motors any more. The Cute Q85 motor is only listed for 201rpm (26" wheel 25km/h rated speed) and 328rpm (16" wheel 25km/h rated speed). These would not work effectively on a 20" rim, as the 201rpm motor would only power to 20km/h and the 328rpm motor would be useless for hill climbing.

BMSBattery used to do deals outside their web shop, and do special orders, but don't seem to want to do this any more. They usually don't answer messages unless the answer is yes. They also have rather misleading advice on their website suggesting that their hub motors can be used on various rim diameters.

Trying to find another source, I recently bought a couple of motors from Elifebike, sold as QQ-M85F, which I believe are the same BMSBattery sell as Cute or Q85. I ordered 20" size the first time, then received a motor very promptly labelled 16". When I checked my invoice I found I seemed to have ordered 16" by mistake. I took this as my own mistake and ordered a 20" motor very carefully, which also arrived about 10 days later labelled 20". Tonight I finally put both motors on a wheel truing stand and tested their speeds with a tacho. Both 16" and 20" motors had a no-load speed of 250rpm: the no-load speed of a 26" motor! The motors are exactly the same but for a stick-on label. It looks like Elifebike have one box of 26" motors and print out a label for whatever size rim is ordered. I'll try to sort a return or refund, but I don't think I'll be able to get a 20" motor from them.

It looks a bit like these little online sellers can't get stock, and are flogging what they have as they can.

Can anyone advise where I can get 200w-250w, 20", front hub motors, preferably Bafang (but I can't be fussy any more)?

Best wishes from Bruce.

 

[d8veh]

You can get the 24v 201rpm Cute Q100 and run it in a 20" wheel at 36v for about 18mph or 44v for about 22mph. I use one in my 20" dahon and it works really well. I have two Zippy 8000maH 6S packs, which fit perfectly in one of those frog cases for a very neat and simple installation.

 

[bdteakle]

Thanks D8veh,

I use 36V LiFePO4 batteries from BMSBattery so this could work well.

What's the peak current draw on your Dahon? Do you reckon this would work well with a 36V 250w approx 16A controller such as BMSBattery KU63?

Bruce.

 

[d8veh]

Yes. I use the KU63 controller with the shunt soldered for 18amps. Nothing seems to get too hot, but I don't use full throttle all the time.

I used a rear motor and put an 11T 7 speed free-wheel on it. Here's a photo:

 

[marshy]

I used a rear motor and put an 11T 7 speed free-wheel on it.

d8veh - assuming you used a DNP 11T freewheel - if so did you need a spacer between the freewheel and Q100 hub?

 

[bdteakle]

To finish off the story: after my postings above I was contacted by an ex-BMSBattery.com employee who works for a new Chinese online supplier: www.greenbikekit.com , saying that she had heard I was looking for 20" Bafang motors. I corresponded and arranged to buy a special order of 6 20" Bafang motors, 3 front and 3 back, for normal price. I paid by Paypal and all arrived in good time (for non-stock items) in good order.
This is the sort of flexibility and service BMSBattery.com used to provide, but had ceased. Perhaps starting a new business makes for a more consumer-oriented approach?
I am currently about to order a battery, charger and other bits from Greenbikekit. Apparently their headway batteries are the same as BMSBattery sell. They've been really helpful in clarifying info about their products, which is (as usual) somewhat hard to get from the website.
I did buy a 26" 24V 350w motor as recommended by d8veh, but haven't got around to lacing it up. I imagine it might offer a bit more speed than the standard 20" Bafang so I'm interested to try sometime.
Bruce.

 

[winkinatcha]

hey mate,

I am currently making controller mods to 26" wheel, 500w 24v kits to bring em down to legal 250w. (plus the 25kph spd limit, plus PAS system to be TOTALLY Aus legal)

Let me know if yer interested, in either the how to, or the actual kits themselves...

Joe

 

[Jeremy Harris]

Thanks for the heads-up on greenbikekit, it helps confirm something I've been told on my BMS Battery thread (I just received the wrong motor from them, and am also looking for one for a 20" wheel).

I'll contact greenbikekit and see if they can supply the Bafang I was after. Knowing they are more likely to send the right stuff is reassuring!

 

[d8veh]

To finish off the story: after my postings above I was contacted by an ex-BMSBattery.com employee who works for a new Chinese online supplier: http://www.greenbikekit.com , saying that she had heard I was looking for 20" Bafang motors. I corresponded and arranged to buy a special order of 6 20" Bafang motors, 3 front and 3 back, for normal price. I paid by Paypal and all arrived in good time (for non-stock items) in good order.
This is the sort of flexibility and service BMSBattery.com used to provide, but had ceased. Perhaps starting a new business makes for a more consumer-oriented approach?
I am currently about to order a battery, charger and other bits from Greenbikekit. Apparently their headway batteries are the same as BMSBattery sell. They've been really helpful in clarifying info about their products, which is (as usual) somewhat hard to get from the website.
I did buy a 26" 24V 350w motor as recommended by d8veh, but haven't got around to lacing it up. I imagine it might offer a bit more speed than the standard 20" Bafang so I'm interested to try sometime.
Bruce.

I think that there is a link between BMSBattery and Greenbikekit - like someone defected and setup on his own using the same supply sources. I don't believe that they stock anything but instead they call it in from local wholesalers, which is why they never seem to have exact details of what they're selling. Hopefully it was the good guys that defected. I've noticed that the names on emails from BMSBattery have changed and the new guys seem to be much more abrupt and dismissive. The only guy I used to get any sense out of was Jack Xie, but I haven't seen his name for a while. I'm definitely going to give Greenbikekit a go next time.

 

[bdteakle]

To update you all on my experiences with greenbikekit.com:
I recently made a second order from them, a battery, charger, spokes, spare BMS/PCM and anderson plugs. Prices were good (similar to BMSBattery.com) but communication was good too. I specified XLR connectors on the battery and charger, and was pleased to find that the XLR plugs were already installed when they arrived. BMSBattery.com have been supplying batteries and chargers with jug cord plugs on both chargers and batteries (charge and discharge sides) and putting other connectors in the box for me to install myself.
So far I'm really happy with service from greenbikekit.com.
I also changed a failed BMS on a 12s Headway battery for the first time (with diagram supplied by greenbikekit.com), so I'm pretty happy about that too.
Here's a photo of the battery and charger:

Bruce.