jorglueke

When ebikes say 350W or 700W is that the rating of the motor or the wattage applied to moving the bicycle? If it's the former what's the efficiency of these motors, how much power goes towards motion? I'm guessing that these are motor rating since cycling at 150W over time is pretty good for a human so even a 350W assist would be enormous.

2old

Normally (if anything is ever normal), the rating is the number of watts that can be input to the motor indefinitely without the motor failing. It's possible to put much more than that amount for short periods.

Robert C

The motor power, however, normal output is well under the motor rating. I find that my 350W hub motor is normally putting out less than 150W. At 200W it is making noise, and it is seldom at that point. My 750W hub motor is almost never over 400W (in fact the only time it is that high is starting from a stop, with a full load).

jorglueke

Even 150W is like getting an extra double of yourself.

chas58

Well, I typically do between 200 and 300 watts continuous, so I need a 350 watt motor. But yeah, my goal with that motor was to simulate me riding a tandem bike with my brother. Nice to double my power output.



You need to go to Motor Simulator - Tools

Play with the parameters and answer your questions. Go crazy (I did). Its an amazing tool.

Here is a graph of a 350watt motor I use. Although the standard controler is rated 15 amps, I find it pulls on average about 10amps over my commute.

J Boz

Apart from as the already mentioned being it's recommended continuous usage, with real world experience it is about half of what it can do before saturation. Meaning if you would likely see no benefit of putting more than 1500w through a 750w motor. Basically the power would just go straight into heat. Not only that the phase wires are too thin to do more and would eventually melt and short for extended periods.

Having said that I have 1kw rate motor I pump about 3.5kw through. You need to go easy on how long you can do that. I also run ferrofluid and hubsinks on it to draw out the heat, and have gone from 14awg to 10awg phase wires to the axle which is too small to go any further in. So at least they draw some of the heat but the bottle neck is apparent and still warms.

Often times motor specs like my lightning rods big block is listed as 3kw, but in reality it can most probably do 10kw, but even at 3kw maintaining a bicycle drivetrain is hard enough.