I managed to shim the v-belt pulley and jerry-rig a motor mount, so I mounted up the little motor onto my Piaggio Boxer scooter, put the v-belt on, strapped the batteries on with duct tape, and shorted the throttle wires, and it ran!
The speed was horrendous, maybe 6 mph on a slight downhill and 3-4 mph on a level surface. But that's fine for the purpose of my test run.
Here are the current specs:
Base model: Piaggio Boxer Mo-ped
Motor: 24V 240 watt from a Razor mini-bike
Batteries: 12 V SLA x 2 (from Razor)
Motor Controller: 24VDC 30A controller (from Razor)
After running it for 10 minutes up and down the street, the motor was extremely hot, hot enough for the label to peel off. The controller was also hot (enough to wrinkle the duct tape holding it on). The batteries seemed fine.
Thoughts:
1. I definitely need to push this up to 48V so I can get more wattage at the same amperage. There's enough space on the mo-ped runners to mount 2 sets of 2 SLAs on each side.
2. The current motor mount blocks airflow to the motor. I need to mount it better so that it is in the direct air current.
3. I need to find a more powerful motor too, while I'm at it.
4. I need to figure out how to get it to be even a higher gear ratio that what I currently have. Maybe find a smaller front pulley somewhere or figure out how to mount a large sprocket on the rear and have it chain-driven.
Anyways, I'm very pleased with myself that it at least works. :-) Now to just make it work better!
Karen
p.s. Photos to follow soon.
Karen,
Sounds like your test run was a success, glad to hear it did get you going even if it was slow. Like everything else sometimes you have to crawl before you can walk and then run. Great work and again good to hear you have a start in the world of EVs.
BTW the reason the motor got soooo hot may be that your gear ratio is too high.
Grandpa Chas S.
Grandpa Chas -
The v-belt I used was a bit too tight, so it caused the rear adjustable hub (which is half of the former CVT) to go to its smallest setting. So my effective gear ratio was 7:1 rather than the 14:1 that I was hoping for. That was causing the poor motor to lope at 500 rpm, which is really much too slow, right? What is the sweet spot for the motor?
I have to go out and get another longer v-belt and then use a smaller pulley, that will hopefully bring me to a 20:1 gear ratio. Which would mean 1200 rpm at 5mph and 2400 at 10mph. That should be better for the motor, right?
I also want to think of a better way to mount the motor so that it's fully in the airstream.
Karen
Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev
Karen,
I think you have the right idea of getting the gear ratio closer to 20:1. I would think this would be very good for the size motor you are currently using. When you get a much stronger motor then 12:1 would work well and of course your top speed will increase with the stronger motor.
Grandpa Chas S.