Converting a kid's dirtbike to electric, with maximum range a priority

[yahodahan]

Hi there! Thanks in advance for any help on this! I've arrived here via many days of searching/etc, realized it's about time to simply ask questions :)

I'd like to convert a small dirt bike, something like a Honda XR80 or similar, to electric.

Most important for me is range: 100 miles minimum. With a 2-3HP motor, a light rider (less than 100lbs), and room in the frame to add lots of batteries, is this realistic?

Motor:
The Cyclone 3000w seems perfect, since we tried a Honda CRF70 (about 3HP), and that was plenty of power. It looks like most the kit items are specific to bikes, so I could go with just the motor and save some cash?

Batteries:
Looks like the "Stealth Bomber" e-bike is using 1500wh, with a more powerful motor but lighter weight, and reaching 50 miles. So, basic guess, I'll need 4000wh? I've mainly looked on the LunaCycle page, and naturally haven't seen any battery packs this size- any other good options, or can they be wired together?

Thanks again!

[Louis]

You'll be best off heading over to www.endless_sphere.com and checking out the builds there. I'd also try googling electric conversions dirt bike or she such string. The cyclone I suppose could get there but you'll ned to find an example or be capable of the engineering. I'd try a few search parameters on google. Or consider getting him into mountain biking.

Good luck!
Sarcasm unintended.

http://bfy.tw/7BDJ

[yahodahan]

Thanks Louis- I've been digging around, yep, but most moto-conversions seem to be heavy and over powered, using lead-acid, etc. Seems to me, what I'm building is closer to an e-bike than a motorcycle :)

Looking through "endless sphere" now, hoping to find something similar :)

[calfee20]

Gasoline and electric horse power are two different things. If you have the same Hp in both, the electric will be more powerful.

[spinningmagnets]

Yes, electric provides full torque at one-RPM. You may have thought this will be an easy calculation, but for best results, please post:

Desired rear tire diameter
desired top speed (these two will give us the RPMs of the wheel)
Desired voltage (these three together decide the kV of the motor)
Pic of frame with some measurements can help in choosing a battery system that may fit without major frame modifications...

Due to battery fitment, the easiest road would be a rear hubmotor. I realize that makes the tail feel less nimble, and a second option might be the Cyclone 3000W or the larger 7000W motors. They would require some custom mount work, and they would also intrude into the space you will want to use for the battery pack...

[Eric Luna]

I think you would have a chance at this with two of the products we added today.

Check out the enduro frame and the 72v 24ah battery which would give you 1600 watt hours.

I think this bike and that battery and the cyclone 3000w are getting pretty close to a perfect combo.... we will be assembling one in our shop this week.

For a kid i woudl do one wtih 20 inch tires...you could also consider the easy route which is heavy direct drive hub motor in the rear.

http://lunacycle.com/electric-enduro-ebike-frame/

[yahodahan]

I think this bike and that battery and the cyclone 3000w are getting pretty close to a perfect combo.... we will be assembling one in our shop this week.

[ATTACH=CONFIG]n14274[/ATTACH]

Hi Eric! Hod did that build go? Would love to see it! That + 20 inch tires would be perfect, I agree!

(sorry for the super late reply...)