Matching controller with rear hub motor?

daluc

1 µW
Joined
Dec 23, 2018
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2
I purchased a 48v 1000w rear wheel kit on ebay. I completed the install and everything worked fine.The pedal assist(pas) has no settings and seems a little to strong. I've contacted the seller to see if I could get a led/lcd display to change the pas settings and they said none was available for it.
I know I can buy another controller that has a display that I can change the pas settings but do I have to match the watts with the motor? I'm looking at a controller with display that is 48v 1500w. Is this too much for my motor even if the volts are the same but different watts? Will it burn my motor? Please advise..........Thanks
 
Your motor will be fine if you don't over heat it. A 1000 watt motor should be able to take a 30 amp controller. What you really need to be careful is that your battery pack can deliver 30 amps without a problem.

:D :bolt:
 
daluc said:
I purchased a 48v 1000w rear wheel kit on ebay. I completed the install and everything worked fine.The pedal assist(pas) has no settings and seems a little to strong. I've contacted the seller to see if I could get a led/lcd display to change the pas settings and they said none was available for it.
I know I can buy another controller that has a display that I can change the pas settings but do I have to match the watts with the motor? I'm looking at a controller with display that is 48v 1500w. Is this too much for my motor even if the volts are the same but different watts? Will it burn my motor? Please advise..........Thanks

If you're only trying to solve for the motor's contribution, another solution might be to increase the size of your front chainring, since it's a cadence based PAS. Even with an LCD and 5 PAS levels, set to 1, I was still getting more motor contribution than I wanted. I like to keep the motor adding about 250 watts at cruising speed (20 mph), with me contributing the other 200 watts. I had to up my chainring from 38 to 46 in order to get the right combination of a comfortable cadence and motor contribution. Of course your mileage may vary, based on what cadence you prefer to ride at, and how much is too much.
 
My experience has been that if you get a system with a crappy PAS, where you're actually ghost pedalling because the motor runs too fast, higher gearing isn't going to help too much.

Match the amps to the motor. If you have a 1000W kit and like how it runs, other than no PAS, the replacement should have the same or higher Amp rating. The KT controllers with their "torque simulation", in my opinion, work well enough for cadence sensing. Doesn't hurt either to get more FET's (drive transistors). A 22A controller with 9 FET's is going to handle heat better than one with 6 FET's.
 
Hello, be careful, i bought a kit from banggood, it's quiet with the original controller.
I tried three other one, and i can't find a controller as quiet as the one from the kit, they are really noisier.

First movie original controller vs kt48 500w (not real sine wave) controller from AliExpress:
[youtube]FaxFeVE7NaI[/youtube]

Second one, S12S torque simulation 500w controller from BMSbattery:
[youtube]usrjIaKGa88[/youtube]
 
First thing to do is remove the PAS sensor, and go with a throttle. It takes time to adjust but throttle control is the best. You don't need a display, or pas. However, adding a speedo can help, and knowing your voltage is very good. A volts display is under 5 bucks.


1 pick a speed.

2 pick the gear that goes with that speed, and leave it there all day.

3 learn to make continuous small adjustments to the throttle so your pedal cadence is perfect in that gear, uphill, down, into the wind, whatever. PAS cannot do this. Ride like this, and your body will love it!

It will be easy to creep up on the speed, but with a speedo you can watch your speed, and keep your cadence at that perfect rpm. Over time, you may adjust to a faster cadence, because its so easy. Don't ride with too fast though, keep it at an rpm that maintains some foot pressure. Too fast with no foot pressure will not add pedal power at all, and will make your ass take all the weight on the seat, leading to butt problems.

now you get the perfect ride, never riding at too fast cadence, or too hard a load for very long. A bit hard to pedal the first 5 feet, but grabbing throttle fixes that easy, then back off to perfect cadence when up to speed.
 
My take on PAS is slightly different, but I think we all may be able to agree on the starting point, which is cadence based PAS is a “dumb” system; not stupid, just not very intelligent. Sort of like how a manual transmission has no built in logic versus an automatic, that down or upshifts based on conditions it is able to determine on its own. With cadence based PAS, it's faster pedaling, more motor contribution, period.

The user has direct access and control over other variables on the bike, like throttle, changing PAS assistance levels, gearing, and of course his/her cadence. He/she also has visual and other sensory inputs, to see the grade the bike approaching, and feeling a head, side, or tailwind. The user can also place the PAS level to zero, and use throttle only, to go full manual (throttle only). A torque based PAS, while better, still leaves other variables in the user’s control, like gearing (not pure manual or auto, but like an automatic transmission with paddle shifters; sticking with the car analogy).

If you think about it this way, the PAS, in any form, is not only pedal assistance, but user assistance, since it handles some of the logic or intelligence applied by the user, over full manual. Cadence PAS being the dumbest, and torque based PAS being a little smarter. The latter should be able to deal with things like head wind or increases in grade, by applying more assistance automatically under those situations, alleviating the user from having to make the adjustment the throttle would provide.

As long as the PAS is not adding too much assistance based on the user’s preference, at the speeds the user prefers to travel on flat ground, the user can choose to use the small amount of logic built into a cadence based PAS, even if it isn’t much. In other words, the user may either prefer to keep their portion of contribution steady (e.g. user contributes 200 watts) or keep the motor’s contribution steady (e.g. motor contributes 250 watts); by controlling the other inputs, like PAS level, gearing (which affects cadence) or pedal effort. He/she supplies all of the missing intelligence to meet that goal. If the user approaches a hill, he/she can increase the PAS level or downshift (increase the cadence), and the “dumb” PAS will increase the motor contribution. Or, the user could just pedal harder, to keep the motor contribution steady, but at some point will need to up the PAS, downshift, or use the throttle, once the hill becomes too steep. Just as a user can learn to use throttle for everything, it’s possible to use even “dumb” PAS for everything, taking advantage of its rudimentary logic.
 
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