I want to convert my son's gas mini bike to electric. It is a traditional tubular frame minibike with a 3 hp engine. My son weighs about 60 lbs and I do not want it to go too fast. The tires are 11 inch diameter.
I have calculated that a direct drive with a 2500 rpm motor, 11 and 80 tooth sprockets it would have a top speed of 11.22mph.
I am looking at a 36 volt 500 watt motor, controller and throttle on your website. I think it needs three 12v 8 ah batteries.
I need some technical feedback on this set up. Does this size motor look appropriate for this conversion? Please make any suggestions, I am rookie at this. Thanks!!!!!
I ran a Motor Power Calculation and with the weight of the rider and mini bike a 500 Watt motor geared for 11.22 MPH will be able to go up a 10% incline at full speed and a 20% incline at half speed. If the mini bike needs to go up inclines steeper than 20% for an extended period of time then I recommend using a more powerful motor.
I ran a Ride Time Calculation which estimates that a 36 Volt 8Ah battery pack will run for 45 minutes on flat ground with a 500 Watt motor. Riding the mini bike up inclines will reduce this runtime estimate though. If you want more runtime then a battery pack made with higher Ah batteries could be used.
We have a kit which is very close to what you need with the exception of the sprockets and chain. It is our KIT-36500-01 which is available on this page:
KIT-36500-01 has 9Ah batteries which are the exact same dimensions as 8Ah batteries however they provide a 12.5% increase in ride time for only $3.00 more per battery so they are a good upgrade to make. The motor in this kit has a four-bolt bottom mounting bracket that will bolt down to any flat surface.
Most gas powered mini bikes use #35 chain and we have a 10 tooth sprocket for #35 chain which fits the motor in KIT-36500-01. This sprocket is item # SPR-3510 which is sold on this page:
We also make custom wheel sprockets for #35 chain which can be ordered on this page:
We sell #35 chain and master links on this page:
We have over 100 more kits available that can be used to convert a gas powered mini bike and make it an electric power mini bike. These kits are labelled as electric scooter power kits however any of our kit that can be used for an electric scooter can also be used for a mini bike. Here is teh search page link to these kits: