bafang bpm and cst 350w 500w

Deleted member 4366 · Nov 30, 2012

I'm not sure of the exact difference between 350 and 500w versions and there,s not a lot in it. They weigh the same, so it makes sense to get the 500w one.

The difference between the CST and BPM is that one takes a cassette gear cluster and the other takes a free-wheel gear cluster. Both free-wheel and can take 8 speeds. I think you can go 9 or maybe 10 speed with the CST. It's main advantage is that you can fit higher quality gears. The motor internals are the same between BPM and CST.

saneagle · Dec 1, 2012

rpurchon said:
so the internals are same between bpm and cassette model,more or less.
am i right that the cassette model only comes in one speed rating.
do you think it would be possible to fit a free hub[cassette] to the side cover of bpm.
is there any difference between 36v 48v volt motors.
cheers richard

The CST motors don't seem to have a code number on. The last one I ordered only did about 18mph, which would be 201 rpm. The ones I'm waiting for are listed as 270rpm, but you never know until you've got them. The BPMs come in a full range of speeds, but it's difficult to find someone selling the one you want, and they never seem to be the speed you expect.

I don't know what you mean by a "free hub". The BPM takes a free-wheel and the CST a cassette. Both free-wheel. You can't fit a cassette to a BPM.

Deleted member 4366 · Dec 1, 2012

rpurchon said:
a free hub is the splined part the cassette [gears]slides on.with the free wheel.
i was thinking it may be possible to machine down a rear hub with free hub on.
and bolt it to a bpm side case.i notice spare side cases are now available for bpm.
richard

A guy did exactly that, and then he sent it to Bafang to show them how to do it. They then used his idea to develop the CST (according to what I've heard). You can get a side-plate with the free-wheel thread from Greenbikekit.com for next to nothing if you want to experiment. the one in the picture is not a BPN, but they have them.
8FUN bldc hub motor covers for bafang motor repairing-Greenbikekit.com online store for electric bicycle components-GreenBikeKit.com

selrahc1992 · Mar 9, 2015

rpurchon said:
could any one tell me the differnce between a bpm 350w and 500w motor.
same with the cst model.
also would it be possible to fit a free hub to the side case of a bpm and make it into cst model sort off.
richard

dear all, apologies for flagging up an old thread, but here goes:

i just got a BPM 500w from BMS battery - it looks identical to this:

http://www.elifebike.com/upfile/dtpic/2012/5S/Q4CQ.2MJWP/ADCPJ1_SYYUB.jpg

ive gone and bravely stretched teh rear dropouts on a well loved old raleigh, and ive screwed on a nice new wide range freewheel. Then suddenly i was stumped: there isnt a locknut that woudl push against teh inside of the frame - a nut with little serations that would be inside the frame pointing out - somoething like the outer nut on this

https://rustybikebell.files.wordpress.com/2012/01/img_0047.jpg

where does one get one and is it the right thing to use? apologies for a noob question and many thanks for advice

selrahc1992 · Mar 9, 2015

selrahc1992 said:
dear all, apologies for flagging up an old thread, but here goes:

i just got a BPM 500w from BMS battery - it looks identical to this:

http://www.elifebike.com/upfile/dtpic/2012/5S/Q4CQ.2MJWP/ADCPJ1_SYYUB.jpg

ive gone and bravely stretched teh rear dropouts on a well loved old raleigh, and ive screwed on a nice new wide range freewheel. Then suddenly i was stumped: there isnt a locknut that woudl push against teh inside of the frame - a nut with little serations that would be inside the frame pointing out - somoething like the outer nut on this

https://rustybikebell.files.wordpress.com/2012/01/img_0047.jpg

where does one get one and is it the right thing to use? apologies for a noob question and many thanks for advice

in case there's anyone out there struggling to fit a bpm 500, here is an endless sphere thread that plots teh (tortuous) route
http://endless-sphere.com/forums/viewtopic.php?f=2&t=49895

Deleted member 4366 · Mar 9, 2015

Wherever you get the motor from, you normally find the washers in a little bag with the nuts and the white connector block that you also need. Have a good look amongst the packing materials.

I wouldn't take any notice of that ES thread. The guy probably found them later unless he chucked them with the packaging.

Please let us know when you find yours!

selrahc1992 · Mar 9, 2015

d8veh said:
Wherever you get the motor from, you normally find the washers in a little bag with the nuts and the white connector block that you also need. Have a good look amongst the packing materials.

I wouldn't take any notice of that ES thread. The guy probably found them later unless he chucked them with the packaging.

Please let us know when you find yours!

many thanks, unfortunately i dont recall seeing that at all - only on teh axle the two outer axl nuts and two antirotation washers, i have a hunch i'm going to have to hope i have the right size bolt, because getting into a tet a tet with bmsbattery and getting it posted seems ambitious, would a bol do the job safely with an anti rotation washer and torque arm?

Deleted member 4366 · Mar 9, 2015

So you have the anti-rotation washers and nuts. You're not missing anything then!
The anti-rotation washers go inboard of the drop-outs. If you have a seven or eight speed freewheel. you will need one or two 12mm washers behind the anti-rotation one to bring it clear of top gear. You might need narrow washers depending on the inside diameter of your freewheel.

On the disc side, you will need one 12mm washer behind the anti-rotation washer to bring the disc caliper in line with the disc.

selrahc1992 · Mar 9, 2015

d8veh said:
So you have the anti-rotation washers and nuts. You're not missing anything then!
The anti-rotation washers go inboard of the drop-outs. If you have a seven or eight speed freewheel. you will need one or two 12mm washers behind the anti-rotation one to bring it clear of top gear. You might need narrow washers depending on the inside diameter of your freewheel.

On the disc side, you will need one 12mm washer behind the anti-rotation washer to bring the disc caliper in line with the disc.

many thanks, that helps a lot (i wondered which side the antirotation washers were meant to go on)- so, to state the obvious - i fill up teh axle on teh drive side with 12mm washers smaller than teh freewheel inside diameter untill it reaches the outside of teh freewheel, so to speak - does teh innermost washer go against teh body of teh motor/cone? teh axle stops being threaded towards teh body of teh motor and i wodner whether that woudl stop a 12mm washer - or doesnt that matter? apologies for describing all of thsi rather clumsy and many thanks

Deleted member 4366 · Mar 9, 2015

The washers go up against the shoulder at the inner end of the threaded bit of the axle on the drive side. I can't remember whether it's a problem on the BPM. but make sure that the first washer isn't touching both the inner and outer part of the bearing on the disc side. You might need a special narrow washer.

selrahc1992 · Mar 10, 2015

d8veh said:
The washers go up against the shoulder at the inner end of the threaded bit of the axle on the drive side. I can't remember whether it's a problem on the BPM. but make sure that the first washer isn't touching both the inner and outer part of the bearing on the disc side. You might need a special narrow washer.

many thanks, i'll do this and see how it works

jonathan75 · May 23, 2015

I've got a Bafang CST 250w (the large diameter version) and was wondering if anyone would know what would be a suitable low-priced controller & LCD for it as I'm struggling a little. I gather around 19 or 20 amps is supposed to be quite good for this - I'm reluctant to go with less as although I want to stay within 15.5mph, I've found my knees are far less happy with pedalling than I'd hoped, so considerable throttle-only operation including on long hills is sought.

The cheapest anywhere appears to be this one, but of course it's only 6 mosfets (14-15amps or so I gather normally), so I'm not sure - will it go up ordinary steepish and/or just long tarmacked hills?

TIA

Deleted member 4366 · May 23, 2015

The KU93 from BMSBattery or the equivalent 9FET one from Greenbikekit would do it pretty well. If you want to use a pedal sensor, get the optional LED display.

jonathan75 · May 24, 2015

Thanks D8veh. It's a shame with the KU93 - it doesn't take an LCD (so no speed control). Unfortunately the Greenbikekit rep told me last night his 9fet controllers don't work with LCD or LED. So I wonder if this one would work ok, https://bmsbattery.com/ebike-kit/553-s09p-500w-torque-simulation-square-wave-controller-ebike-kit.html although it is 22+1amps rather than 20. It is supposed to work with BMS's 's-series' LCD displays, so I think you were saying that means the amperage can be turned down (unless one uses throttle only). If that's true then would it be too much on throttle for a Xofo CST 250w 36v, or a Bafang CST HT 250w?

Perhaps I should email BMS to see if they'll sell an 09-battery-mount integrated controller and display separately without all the brake lever/throttle gubbins, might bring the price down.

Deleted member 4366 · May 24, 2015

I ran my Xofo st 30 amps. It pulled pretty wrll. I fon't know whether the windings are different on yhe 260w version. The S09P will be a good controller gor it, and it foes use current control. Whatever yhe windings of the Xofo, I'd be happy to run it at full power with that controller.

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