Originally Posted by
Maro
Hello, I have a GoldenMotor kit, LIFEPO4 battery, 36VDC with 250W motor (PRO902). I love it, the only problem is that the max speed is about 24-26Km /H.
I can do this much with my road bike.
Would be a problem to buy a 24VDC motor and use it with the 36VDC battery / controller to get more speed. GoldenMotor have two versions of PRO902: 24VDC and 36VDC.
This would be the cheapest option as the battery is veeery expensive. I live on flats, hills not a problem (But very windy).
Any advise would be appreciated.
Thank you.
I did it, and it works fine for me (a tiny Cute Q100 motor). I'll tell you what to watch for.
1st, the controller and the battery have to match - not a problem for you as they are both 36v in your case.
2nd - voltage determines the speed of a motor* (current determines the torque).
So, in my case I had a 24v 200rpm motor (no load speed). Like you, that gives me a road speed (with a full sized wheel) of 24km/h. My target road speed was 35kph. Since speed is directly proportional to voltage, 24kph * 36v/24v = 35kph.
That is a big jump in speed. The potential pitfall is that if you can't pedal fast enough to keep the bike in that speed range most of the time, you may overheat something. I do not recommend this for a heavy rider or for climbing hills. But if you put some effort into pedaling, ride somewhere flat, and can keep the bike around 35kph when cruising, you'll be fine.
* motor speed is determined by the number of windings and voltage. Typically when offering a motor in multiple voltages, the manufacturer will change the number of windings so that the motor speed is the same if matched with the appropriate battery voltage.
Also, my "unassisted speed" is 25-30kph, so in my case 35kph with a motor works out well.