First, I built a normal motorized bike from a 4 stroke kit from bikeberry. Bought the kid, found a bike to put it on, upgraded some components and had a little bit of fun. I had a 48 tooth rear sprocket and had a good amount of torque, but a top speed of 19mph and wanted to go a little faster. So, I got a 36 tooth rear sprocket and before actually trying it out, I assumed it wouldn't have enough torque to get up the hills around me (I do weigh 260 pounds) and I didn't want to peddle (really, I want a motorcycle, but I don't quite have enough money for one). So I looked into getting an electric front wheel kit. I decided on a 250w 36v kit.
While installing that, I removed the crank assembly and currently have a cross bar set in place through the bottom bracket to use as foot pegs. It works well, but it's pretty ugly.
I bought a trio of 12v scooter batteries to power it, mounted on a rear rack in a backpack. They are relatively high quality lead acid, sealed gel type bateries. So a bit more stable than regular lead acid and don't care about orientation, but they are just as heavy (Around 8 pounds each). I'm thinking of upgrading to LIon or LiPo cells in the future.
Anyway, I am wondering when I should charge my 12v packs. I charged them at the beginning of the season to about 14.5 to 14.8v each and from being used a little and sitting, they are all around 13.3 to 13.5v. I know it's not good to charge them whenever, unless you're shoving lots of amps into them whenever they are being used, so at what voltage should I charge them? I monitor them by just testing them with a multimeter every once in a while. Though, the battery level indicator on my LCD readout on the bike seems relatively accurate.
So, it does work really well. The gas engine does have less torque, but It will still accelerate with me. But with the electric motor helping it, it's very quick. The electric motor will help the gas engine up to 15mph and with the smaller rear sprocket on the gas engine, my top speed is about 26. But, I still have enough torque to climb the hills around me without needing the electric motor.
I didn't expect it, but the LCD that reads out info for the electric motor still reads out the correct speed even after 15mph, so that's cool. I hooked up a tachometer to the engine, but used my phone before to click speed.
So yeah, it was a cool project and I at least accomplished my goal of not needing the crank set. What I want to do next is to build a lighter weight battery pack and find a better foot peg option. Maybe make a nicer looking seat.
I'll post some pics soon. I have to wait for the rain to pass and put my battery back onto the rear rack.
While installing that, I removed the crank assembly and currently have a cross bar set in place through the bottom bracket to use as foot pegs. It works well, but it's pretty ugly.
I bought a trio of 12v scooter batteries to power it, mounted on a rear rack in a backpack. They are relatively high quality lead acid, sealed gel type bateries. So a bit more stable than regular lead acid and don't care about orientation, but they are just as heavy (Around 8 pounds each). I'm thinking of upgrading to LIon or LiPo cells in the future.
Anyway, I am wondering when I should charge my 12v packs. I charged them at the beginning of the season to about 14.5 to 14.8v each and from being used a little and sitting, they are all around 13.3 to 13.5v. I know it's not good to charge them whenever, unless you're shoving lots of amps into them whenever they are being used, so at what voltage should I charge them? I monitor them by just testing them with a multimeter every once in a while. Though, the battery level indicator on my LCD readout on the bike seems relatively accurate.
So, it does work really well. The gas engine does have less torque, but It will still accelerate with me. But with the electric motor helping it, it's very quick. The electric motor will help the gas engine up to 15mph and with the smaller rear sprocket on the gas engine, my top speed is about 26. But, I still have enough torque to climb the hills around me without needing the electric motor.
I didn't expect it, but the LCD that reads out info for the electric motor still reads out the correct speed even after 15mph, so that's cool. I hooked up a tachometer to the engine, but used my phone before to click speed.
So yeah, it was a cool project and I at least accomplished my goal of not needing the crank set. What I want to do next is to build a lighter weight battery pack and find a better foot peg option. Maybe make a nicer looking seat.
I'll post some pics soon. I have to wait for the rain to pass and put my battery back onto the rear rack.
