Is a sinewave controller healthier for a motor?

General Discussion about electric bicycles.
Post Reply
ebike11   1 MW

1 MW
Posts: 1524
Joined: Nov 16 2013 8:01pm
Location: far away

Is a sinewave controller healthier for a motor?

Post by ebike11 » Dec 26 2020 8:49am

Hi guys
I have a mxus 36v motor and battery pack on a spare bike. Im jsing just a cheap 22A controller from aliexpress. I know it may be a weird question but would a sinewave controller, which is completely silent, be healthier for an ebike system/motor than a cheap non sinewave.type?
The reason i ask is because the non sinewave controller causes a bit of noise and grunting, especially on take off but even full throttle it still whines a bit.
Do these noises affect or hurt any componants??

My sinewaves on my other past bikes were silent in all ranges.


larsb   1 MW

1 MW
Posts: 1984
Joined: Dec 10 2014 5:12am
Location: Gothenburg, Sweden

Re: Is a sinewave controller healthier for a motor?

Post by larsb » Dec 26 2020 10:44am

No, you lose a bit of efficiency but it doesn’t matter

Just don’t overpower and burn your motor (which you can do with any controller type.)

User avatar
MadRhino   100 GW

100 GW
Posts: 7213
Joined: Sep 03 2010 5:28pm
Location: Montreal QC Canada

Re: Is a sinewave controller healthier for a motor?

Post by MadRhino » Dec 26 2020 2:03pm

Driving a simple 3 phase brushless motor smoothly and silently, does make an impression of reliability but it is only an illusion. A noisy, cogging motor will last just as long if it is fed the same current, performing equal acceleration and speed. When you tune the hardest acceleration, a motor does make some noise though, so silence is sometimes the result of softer start and that, may have some effect on durability.
Make it fool-proof, and I will make a better fool.
Current bikes
Trek Session 10 mod. Variable geometry. 70mph
Santa Cruz V10. 50mph

User avatar
motomech   1.21 GW

1.21 GW
Posts: 3519
Joined: Sep 11 2010 12:21am
Location: Tucson & Punta Cana Baja Mexico

Re: Is a sinewave controller healthier for a motor?

Post by motomech » Dec 28 2020 1:19am

The answer to the title question is no,...and yes.
A number of years ago, I played around with running high power thru a MXUS geared mini. By "high power", I'm talking about 14S and 16S LiPoly (nom. 54V & 62V) and a 25A Grineon & a Lynn 22A Mini Monster, both square-wave 6 FET's. The Lynn was a hard-hitting little hot rod and even on just 14S, I could feel the motor "hammering" thru the bars.
Now I never ran a sine-wave at those levels, they were puny little 14 A units and they never liked the odd Voltages of Lipoly. But I would think the hammering was largely a function of the square-wave topography, so one would think a sine-wave would be transmit less of the shocks.
I did have a chance to compare the two types of controllers, both around the 15A level on the very tiny and power sensitive Cute (Q100) CST. The sine-wave had a "softer" start-up and felt easier on the motor.
So I would suppose the answer is, no, not much different on low power, but for idiots like me that try and run too much power thru a sm. motor, I think a sine-wave could act like a cushion.
These days I run 14S and a soft-start Square-wave on my Q100H motors and that seems about right.
Motomech '11 Motobecane Fathom team, frt. mounted, recycled SWX02 from a Jump rental, 14S (52V nom.) Turnigy LiPoly, PSW Power 9-FET 20A controller. Mean Well HLG-320H-54A, Schwalbe Marathon's, 27 to 28 MPH.

User avatar
dogman dan   100 GW

100 GW
Posts: 35849
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

Re: Is a sinewave controller healthier for a motor?

Post by dogman dan » Dec 28 2020 7:09am

Well, I'm a dumb shit with an ag degree, not EE, But I agree with the first two answers.

I never vibrated a motor to death with square controllers. I killed them with too much load, too much watts, or both simultaneously.

Hard to say what kills a motor faster, I've killed motors in under 30 min with only one of the two, when its overloaded enough, or over volted enough.

You can judge how big your overload is by the grunting though. But that is different for each motor, and some will have one or two looser wraps in the winding that grunt more than other motors of the same type. I just mean when it really grunts more than it normally does, its in that overloaded condition that you should try to get out of. With more pedaling, losing some cargo from that trailer, or turning back downhill if its been doing it for 20 min.

Post Reply