Need good advice! Can I do this to make my ebike faster?

[dollyball]

HI! I have a 48V 350w Bafang rear motor ebike. Here are the specifications I found on the surface of the motor and the box of the controller(see attached pictures).
Can anyone tell me if I can increase the speed of the bike by using a controller with a higher maximum current(Now 18A)? And what is the highest maximum current such a motor can manage? I will be very grateful if anyone can enlighten me about this. THANKS!!! Joe

 

[6zfshdb]

I'm afraid I can't offer much help here since this is a complicated question with no simple answer. Motor manufacturers usually under rate their specifications for quality and longevity purposes. Just how much extra current a motor will handle depends on many factors. This includes the motor windings, brushes (if any) and most of all the ability of the housing to dissipate heat.

When I was a kid, I used to race model boats. I went to junk yards and bought vehicle power window motors rated at 12V. I would mount them in my models and power them at 48V to get more speed. Some motors could handle the extra voltage & current and others burned up almost immediately. None lasted very long.

It's one thing to experiment with cheap junkyard motors, it's another with an expensive e-bike motor. Whatever you do is sure to shorten it's lifespan.
I would suggest contacting the manufacturer and see if they can help with your question. Maybe someone here with Bafang experience will offer a suggestion.

 

[dollyball]

Thanks a lot for your advice! And your jump from 12V to 48 V proved another failed big leap forward, from which we should learn something.

 

[Ken M]

I'm afraid I can't offer much help here since this is a complicated question with no simple answer. Motor manufacturers usually under rate their specifications for quality and longevity purposes. Just how much extra current a motor will handle depends on many factors. This includes the motor windings, brushes (if any) and most of all the ability of the housing to dissipate heat.

When I was a kid, I used to race model boats. I went to junk yards and bought vehicle power window motors rated at 12V. I would mount them in my models and power them at 48V to get more speed. Some motors could handle the extra voltage & current and others burned up almost immediately. None lasted very long.

It's one thing to experiment with cheap junkyard motors, it's another with an expensive e-bike motor. Whatever you do is sure to shorten it's lifespan.
I would suggest contacting the manufacturer and see if they can help with your question. Maybe someone here with Bafang experience will offer a suggestion.

Some direct drive and gear hub motors have thermal protection so you can increase the current a bit without risking damaging the motor. Depending on your riding conditions (hills, weight, etc.) you may never even get the motor hot at the higher power levels.

You'll find that some are injecting ferrofluid into their motors which creates a much better thermally conductive path for stator heat to get to the rotating hub itself. It's certain effective but not sure how long it last and whether or not you may need to open and clean out the old ferrofluid occasionally (like changing oil in a car). Something to consider if you want to learn all the tricks to increasing the power levels.

There are a lot of people on this forum that will try to scare you away from ever getting assist past 20mph and certainly not pass the Class 3 speed of 28mph but I feel comfortable riding a bike in the mid-30s when I'm on a smooth bike lane that is wide open. Just ride at what you feel is a comfortable & safe speed.

 

[harryS]

Motor speed is determined by your voltage, which isn't changing here. You need more voltage.

You're already at 48V, and the next size up is usually 52V. Go look at the grin simulator. While he only rates motors that he sells or used to sell, you can see the relative increase in speeds for 52V vs 48V. You can also go between 20 and 45 controllers, and while torque goes up, speed does not. Is it worth a new battery for another 2 or 3 mph? For most users, the big jump is going from 36V to 48V.

https://www.ebikes.ca/tools/simulator.html

Motors should run all day on flat ground at their rated current. The above tool suggests that is true. As you start going up hills, that is when motors overheat. His simulator predicts that too.