old motors inefficient?

monster

100 kW
Joined
Jun 17, 2007
Messages
1,410
Do motors loose efficiency with age?
I have a 15 year old crystalyte 406 that still works!
But it seems to drink the juice twice as fast as it should.

Is there a way to refurbish it?
I have checked the halls and they're all working.
 
There is little to cause inefficiency in a hub motor other than perhaps holes in the winding insulation. My first suspect would be the controller. Or a change in your tendency to run at max speed and full throttle.
 
magnets will get weaker over time.
tis' a given with rare earth magnets.

but that's just me making assumptions and not having the motor/controller in front of me
 
>But it seems to drink the juice twice as fast as it should.

And you're sure it's not your battery?
Because that's a part that will actually get worse with use and age.

As far as I know permanent magnets will only demagnetize with heat.
 
Well, on our bike ride she used 2 battery packs to my one. So 2 duff batteries?
 
The only way to know for sure is to connect some kind of energy meter and measure what comes out of the battery over the course of the ride. Make sure tire pressure and such is constant through out your testing.
 
Overheating does affect motor efficiency, cooking the varnish and wires insulation, as well as weakening the magnets. Time and mileage, are wearing the bearings. So yes, an old motor can have a poor efficiency.

Batteries are losing some of their capacity with usage. That is the major cause of range loss on ebikes. Another cause is corrosion in connectors and wiring, that can make dramatic loss of efficiency, just before failure.

You need to test and measure, to diagnose. Every ebike owner should have the tools of the trade.
 
I have wattsup meters i could use. I suspect they will just tell me what i already know.
 
The venerable 40X series should not degrade a measurable amount over time. If you overheat the magnets, the classic symptom is less power and a higher top speed.

Shorter range is the classic symptom of an older battery pack that has lost some of its capacity.
 
Older battery.. demagnetized stator.. the answer is in measuring.
We can only provide guesses until you provide data ;)
 
I'm guessing that the bearings are not necessarily worn, but have drying grease that is making them stiff.
 
No, it wasn't, but its efficiency should not be horrible, like 50% less.

Could be anything, from battery issues to cooked magnets. Pretty hard to cook an old 400 motor, but possible if it was ever fed 72v for sure.

I'd be suspecting batteries that are weak, perhaps not able to stand the discharge rate, but another possibility is the 400 motor is a poor winding match with your wheel size, and or the type of riding.

Efficiency in some types of ride can vary greatly. For example, the 406 is a bit faster wind motor and it is asked to start and stop a lot, it will not be running near as efficient as a slower wind motor like a 408, and way less efficient than a slightly slower wind geared motor, when asked to stop at a light every block. Both run about the same at speed, but one starts up more efficient. I find a 20% difference is common, but not 50%. 20% was comparing a 407 type motor with a larger diameter 7 turn dd motor, or comparing the large 7 t dd with a 10t geared motor, with a ton of stop signs on the route.

But on an open flat road, both would run with near identical efficiency.

And then, there is how hard you pedal.

Basically, you are running an experiment with 3 or more variables, which is not science. only one variable gets you science. You have two riders, different motors, and different batteries. Id expect some noticeable difference.


Repeat the test with you riding the same route, same pedaling effort, and same weather, using the same battery on both bikes.
 
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