Weight to Energy ratio

Hello all, I am new to this forum, but enjoy it all the same. I am thinking about building a 3 wheeled motorcycle EV, but I am wondering about what kinds of things I will have to add. for instance, for one seat, (I weigh about 160 lbs) how many batteries (not LiIon batteries, they are too expensive, unless they are just WAY more efficient for my project) would it require if I wanted to get 80 miles per charge. Is that a practical goal even though it would just be my weight on a small frame? also, what would be the most effective way to charge this anywhere? thanks for the help.

Have you checked out the ZERO electric motorcycle? www.zeromotorcycles.com

The reason I mention it is because it’s a 140lb bike with a 58volt/35Ah battery pack, using an Etek motor (20HP) and has a 40 mile range. It uses a 45lb LiIon battery pack and recharges on 110 or 220.

Using the zero as reference, you can see if you can keep your motorcycle as light as possible in other ways, but not skimp on batteries (ie: get higher Ahr ratings).

If you use a programmable controller such as an Alltrax, you can limit the current output which will limit the available torque thus giving you more range. I helped a friend put a 4.5HP Mamotor on a Razor MX650 Dirt racer and it’s just flat-out scary - not to mention dangerous. That tiny motorcycle frame just was not designed to go 40MPH, the brakes were not designed to stop it after going 40MPH :slight_smile: and the torque? Well, I weigh 240lbs and the front wheel comes up despite the gearing set up more for speed!

Anyway, when the controller is programmed for full power available, the little bike just bucks all over the place but it only has about 10-15 minutes of usable charge. When the controller is toned down a bit, limiting both the current and top speed (yet still getting about 30MPH out of it) the range is improved drastically, however because of the earlier high speed/torque testing the brushes wore out during range testing. :slight_smile: It’s still a fairly new project so we have a learning curve. Some gear ratio tweaking, controller programming, new brushes and we’ll be in business. Then it’s on to building a small motorcycle with an Etek motor.