mini bike build

[inonickname]

For a motor you could get an old gofer (like mini golf carts that old people ride around) or perhaps something from a scooter or golf cart. Golf cart may be a little large though.

[Carlman]

As much as im interested in these projects they do not belong here. Theopia is the place for this mate.

[Big-E]

You may need a smaller sprocket. 60 tooth will definitely give you lots of torque and good acceleration, of course, your wheels are small. I know on my 26" wheel, a 44-tooth sprocket will allow for speeds around 35mph on my gas bike.

there are good sprocket size calculators out there, here's one:

http://home.earthlink.net/~gellett/banshee.htm

and here's another one:

http://www.minimotogarage.com/ecm_speed_calc.html

You need to know the max RPM of the motor, which should be stamped on the case, or listed somewhere in the specs of your specific motor. if anything, just make an educated guess.

[jon_89]

okay so from what I got with an 10 inch wheel, 3000 rpm, and a 11 tooth motor sprocket to get 20mph I will need a 38 tooth wheel sprocket. The proble is I dont see how to get the sprocket off. Would this still leave me with good torque?

[rcman50166]

You guys are forgetting that electric motors are way more efficient and torquey than it's gasoline counterpart. 50hp electric motors will move a car for sure. 650 watt is fine. But when I wanted to go for a fast vehicle when I was planning out my go kart, I looked at 2 1200W motors, just for kicks

[Moonbogg]

As much as im interested in these projects they do not belong here. Theopia is the place for this mate.

This is non spudgun related though. What does the forum mean by non spud gun related?

[jon_89]

Another question is about charging time. For now I will be using 6 12v 12ah sla batteries. I will make two 36v 12ah packs for a total of 36v and 24ah. How long will it take to charge at 2 amps?

[rcman50166]

http://www.greenbatteries.com/batterycalc.html
14.4 hours

[Big-E]

nice... It sounds like you have a handle on this project. As for removing the sprocket, I have no clue. Maybe if I had the bike in front of me



Oh, rcman, I had not forgotten that point about electric motors, that's why I told him 650 watts should be fine, I didn't feel the need to bring it up, But you're totally right; Example: The engine I'm putting on my bike is just under 2 HP, the motor he's planning to use would be able to do the same task, and it'd probably get to speed quicker.

Actually, the 750 Watt : 1HP ratio isn't always accurate, I believe it's more a range between 600 and 800 watts. It's also depending on the controller (and motor) you use, as some are more efficient and better engineered than others. but a good controller will run a junk motor better than a junk controller

[rcman50166]

736 watts = 1 HP

[Carlman]

As much as im interested in these projects they do not belong here. Theopia is the place for this mate.

This is non spudgun related though. What does the forum mean by non spud gun related?

What I have learnt is that even though this is made for non spudgun projects people do not like posts in here when they can be at theopia. Maybe im wrong and i realise its different to the 'check this game out' threads.

[dewey-1]

736 watts = 1 HP

I thought it was 746 watts=1 hp.

My old age and memory could be failing me.

[rcman50166]

Upon further inspection I have found you are correct.
1 hp = 745.699872 watts

[jon_89]

Well I was going to use this http://electricscooterparts.com/speedcontrollers.html. Scroll down to the 36v 1000w controller.

[starman]

You biggest challenge may be finding space to mount the 36v worth of batteries. What size batteries had you planned to use?