It only does run for a minute - then it shuts down. My theory, however, is since the fan isn't attached that the shaft is spinning faster hence the motor running faster... so even while the bike it running it could be sucking the life out of the battery. Any takers?
Yeah. The motor will always turn at the same speed
unless there is a load on it... Take the fan off and it will turn at the same speed it was before, (unless you have a massive fan blade)
Without the weight of the fan blade the motor in theory would use less power....making you concept the exact opposite of what actualy happpens. But you'd never be able to measure the difference with common multi-testers.Basicly the power use is the same.
For example, your Dremel tool can spin at 20,000 rpms without an attachment. Put one on, and it may take a nano secound more to reach it, but it will still turn at 20,000 rpms. That is the set speed of the motor.
Take the tool and press the attatchment against a work surface and if you apply too much pressure, you can not only slow the motor down, but make it stop.
If your battery is die'n it is because you either have a bad battery, your charging system is not working, or you have a crossed circuit somewhere that is shorting out the battery. Or some or all of the above. The fan motor uses the same power whether the fan blade is connected or not. And as this does not normaly hurt the battery I would guess you have other issues besides the broken fan blade.