Just wondering about the BPM 48v 500w motor - which RPM should I get? Lower speed means more torque which I need because of the steep hills, but my calculations show that 201RPM in a 26" wheel is about 15mph. Is 201 the maximum speed or is that the speed with the most power/torque and the motor will go faster?

 

There is a 305RPM option on the ELife site that I've just seen.

Edited November 19, 201213 yr by BAH48

201 rpm is at 36v. A 36v battery will be 40v, so you get proportionally more speed. I have a 201 rpm front one, which used to to do about 18 mph, but then I discovered that you can get more speed by joining the green and black wires on the three speed switch connector on the KU93 controller. I don't understand how this three speed switch works because on my code 13 500w rear with KU123 controller, I get about 20% boost, on my Dahon with Q100 and KU63 about 10%, but on my 350w CST (same internals as BPM) the speed increases from 20mph to 33mph!. On other bikes/motors, I get no boost with the same controllers. Saneagle got about 15% with his Q128 and KU63.

 

If you get the 36v 201 rpm version and run it at 48v, you'll get 33% more speed.

 

BMSBattery have sent Code 17, code 15 and code 13 as 201 rpm versions, but the different versions have a huge difference in speed. You could try asking them first which ones they'll ship. Youmight get a more sensible answer from Greenbikekit.com.

 

The code 13 to me is the best because it has very strong climbing with KU123 controller and will easily maintain 20 mph on the flat

OK thanks for that, I'll get the 201 and take it from there, I guess it will become clearer with some hands on experience.

Hi d8veh

 

On your 350w CST you had mentioned that your speed increased from 20mph to 33mph,how much distance/range at present have you lost by connecting these two wires together?

 

Mountainsport...

I've only tried it up my road like that so far. I'm a little worried about running it like that because I'm not sure what's going on. Torque seems to be the same, which isn't enough to reach 33 mph. I need to fit a meter to see what's happening.

 

I can't figure this speed thing at all. When I first tested the motor with KU63, it did 22mph normal and 27mph with wires joined, which I thought would be perfect. but when I tried it on the bike with KU123, speed was down to 20mph no load, which was about 18mph on the road. Then I got the 33mph no load by joining the wires. It seems that different controllers give significantly different speeds.

OK, did some research and know a lot more about codes now.

 

Endless-sphere.com • View topic - Bafang Bpm, how many RPM?

 

I'm thinking about a Mac 500 from Emissions Free - now em3ev.com. It's more expensive but you seem to be able to specify exactly what you want and get it.

I see that jayuk bought one a couple of years ago, anybody got one?