Just thought I'd copy and paste a reply, cell_man aka Paul from EM3ev, posted on Endless Sphere, reference the best way to use a BBSxx when climbing steep hills.
He is quite an authority on all things electric bike, and has sold thousands of BBSxx kits, so knows from his repair returns, how units are getting damaged.
'' It is a very bad idea to go up steep inclines with the bbs02 in a low PAS level (I don't like to call it an assist level, as that is not how it works). The motor will not be turning fast enough (in a low PAS level) for it to operate efficently and also the controller is working very hard, to drive the motor at a low rpm (where phase current is high).
Frankly, if a high PAS level is too fast for you to pedal, you'd be better off selecting the lowest gear possible and using the throttle to spin the cranks to a fast pace, and not pedal at all The lowest pas level is not a low assistance, it is just slower and can still provide enough power, to put the motor itself and the controller, to be put under considerable stress.
In my experience, the people that think they are going easy on the kit by using a low PAS level, would often be those thst were blowing controllers, sometimes repeatedly. The guys that thought they were using the kits harder would typically have less problems with blown controllers, as they would generally keep the motor spinning fast, where it is less stressed. We've sold lots of kits, so this is real experience, not just an opinion.
The controllers in the bbs02 are now much more reliable, due to the better mosfets used, and i think the firmware has improved also. Even still, it is always best to keep the crank rpm fast and the gearing as low as possible when the motor is working hard on a steep incline.
I'm sorry if that doesn't suit your riding style, but these are basic facts, it's a middle motor and the entire point of these motors is to use the gears to make best use of the motor, not to use the motor in a way where efficiency is low and the system is strained. If i could, I'd make the motors too weak at low rpm to do any damage and force users, to use the gears properly, that way reliabilty would be improved IMPO ''
He is quite an authority on all things electric bike, and has sold thousands of BBSxx kits, so knows from his repair returns, how units are getting damaged.
'' It is a very bad idea to go up steep inclines with the bbs02 in a low PAS level (I don't like to call it an assist level, as that is not how it works). The motor will not be turning fast enough (in a low PAS level) for it to operate efficently and also the controller is working very hard, to drive the motor at a low rpm (where phase current is high).
Frankly, if a high PAS level is too fast for you to pedal, you'd be better off selecting the lowest gear possible and using the throttle to spin the cranks to a fast pace, and not pedal at all The lowest pas level is not a low assistance, it is just slower and can still provide enough power, to put the motor itself and the controller, to be put under considerable stress.
In my experience, the people that think they are going easy on the kit by using a low PAS level, would often be those thst were blowing controllers, sometimes repeatedly. The guys that thought they were using the kits harder would typically have less problems with blown controllers, as they would generally keep the motor spinning fast, where it is less stressed. We've sold lots of kits, so this is real experience, not just an opinion.
The controllers in the bbs02 are now much more reliable, due to the better mosfets used, and i think the firmware has improved also. Even still, it is always best to keep the crank rpm fast and the gearing as low as possible when the motor is working hard on a steep incline.
I'm sorry if that doesn't suit your riding style, but these are basic facts, it's a middle motor and the entire point of these motors is to use the gears to make best use of the motor, not to use the motor in a way where efficiency is low and the system is strained. If i could, I'd make the motors too weak at low rpm to do any damage and force users, to use the gears properly, that way reliabilty would be improved IMPO ''
