From s06s to s12s with 36v

[patpatbut]

I want to gain some speed for my bafang cst 250w would than help if I switch the controller to s12s?

Pat

 

[Deleted member 4366]

I doubt it. The only controllers that can give a speed boost are the KU63, 93,123 and some other controllers with a three-speed switch, where the high position of the switch changes the timing to get an extra couple of mph.

How fast does you motor go at the moment? Can you remind us where you got it from (link)? Do you know its specification nominal voltage and RPM?

 

[patpatbut]

On flat 18pmh max. I thought s12s is 23a so it might give a little boost

I got this motor from GBK

http://www.greenbikekit.com/bafang-cst-bldc-motor.html

 

[Deleted member 4366]

Your motor is maxed out at that speed. You could give it 100 amps and it won't go any faster. You need more volts. It's speed will increase in proportion.

 

[eHomer]

I'm following this thread with a lot of interest, because I considered buying the S12S over the S06S for a different reason.

As it's not much more expensive from BMS, (especially when you factor in the shipping), I was thinking it would be "heavier duty" than the S06S, and far less stressed even when carrying the maximum amps that a 350w motor could draw, (about 15 amps, I believe).

I thought there was a danger of frying the motor more easily though, if it was ever overloaded (eg, slow speed, steep hill), because the shunt could pass so much more current than a correctly matched controller ?

Isn't it important to reduce the shunt resitance, to minimize the risk ?

I'm a fan of the sine wave controllers now. After hearing about them from Dave, I replaced the KU65 on my 250w front motor "kit" bike last year with an S06S, and it was much smoother and quieter, with a much better panel, more adjustable PAS, and throttle start.

 

[Deleted member 4366]

Yes, correct. A S12S will fry a 250w motor. It only has one shunt, so not easy to increase the resistance for less current. You'd have to remove the shunt and replace it with a longer piece of shunt wire, or you could use a Cycle Analyst limit the current.

 

[patpatbut]

Yes, correct. A S12S will fry a 250w motor. It only has one shunt, so not easy to increase the resistance for less current. You'd have to remove the shunt and replace it with a longer piece of shunt wire, or you could use a Cycle Analyst limit the current.

Oh does it apply to my 250w bafang CST motor? I thought it would take more amps as it is a huge motor...

 

[Deleted member 4366]

Oh does it apply to my 250w bafang CST motor? I thought it would take more amps as it is a huge motor...

We don't really have any data yet on what can be done with the BBS01. It would be best to take it in stages, and see how hot it gets.