Hi all,
I have been lurking for a bit, but finally decided it was time to post and start planning the build.
Last year I picked up a Mongoose CX 24v450 off Craigslist for $50, the batteries were junk and the forks were bent from when someone backed into it in the garage, but other than that it was in good shape. My LBS sold me some cast off RST Gila forks for $10 and picked up 2 12v12ah SLAs from Chrome battery and we were up and running.
The intent was to have a chase vehicle to run around with when my 6 year old son was riding his Razor MX-350 (older model with the suspension), and later to have for him to grow into.
But instantly I fell in love with it, even in the slow stock form. I added bolt-on passenger pegs to the rear so I could ride 2-up with him back and forth to school on nice days (it is only a couple blocks away), and the stock little motor actually carries us both without smoking.
Anyways, I definitely would like some more speed. I figure my options are to try and see what I can get out of the stock motor at 36V or go with a bigger motor at 48V? The terrain is mostly flat or slight grades, 80% street, 20% park/grass. 10 mile range at WOT would get me everywhere I need to go and back comfortably. Any more range would just be gravy.
Option 1, lower cost low speed toy:
So, keeping the existing 24V 450W motor and going to a 36V LiFePO4 battery pack (and upgrading the controller if I smoke it), can I get 20 - 25 MPH out of it with 20" tires, assuming it is just me at 200 lbs? I would stick to about 15 MPH when I have my son on with me... I also assume this means coming up with a cooling solution for the motor as well. This would be for running around the neighborhood, to Sonic, Walgreens, etc.
Option 2, higher cost errand runner:
(I had a 66cc 2 stroke bicycle that I used in this capacity, but it was a nonstop maintenance project until I blew the motor. I then sold off the parts and used the $ to restore a go-kart for my son)
If I go the high speed route I would like to be able to cruise at 35 - 40 MPH (errand running vehicle to Target and such, 5 miles round trip, 35 MPH backroads). I think I will have to get a bottom bracket crank extension for the pedals, but would like to retain them if possible. Using a gear ratio calculator, looks like I can hit those numbers easily with an 11T front sprocket, 44T rear, 20" tires and 3000rpm. So I was looking at the 1000W, 48V MY1020-B at tncscooters? How would take off torque be with something like that?
Or is the wheelbase too short for these kinds of speeds?
Option 3, staged upgrade:
Is it possible to reach my goals with option 2 using only 36V? If so, I can just upgrade the battery to a good 36V pack first, then cruise around at lower speeds until I get the time and $ to upgrade the motor, controller, sprockets, etc.
Thanks all!
I have been lurking for a bit, but finally decided it was time to post and start planning the build.
Last year I picked up a Mongoose CX 24v450 off Craigslist for $50, the batteries were junk and the forks were bent from when someone backed into it in the garage, but other than that it was in good shape. My LBS sold me some cast off RST Gila forks for $10 and picked up 2 12v12ah SLAs from Chrome battery and we were up and running.
The intent was to have a chase vehicle to run around with when my 6 year old son was riding his Razor MX-350 (older model with the suspension), and later to have for him to grow into.
But instantly I fell in love with it, even in the slow stock form. I added bolt-on passenger pegs to the rear so I could ride 2-up with him back and forth to school on nice days (it is only a couple blocks away), and the stock little motor actually carries us both without smoking.
Anyways, I definitely would like some more speed. I figure my options are to try and see what I can get out of the stock motor at 36V or go with a bigger motor at 48V? The terrain is mostly flat or slight grades, 80% street, 20% park/grass. 10 mile range at WOT would get me everywhere I need to go and back comfortably. Any more range would just be gravy.
Option 1, lower cost low speed toy:
So, keeping the existing 24V 450W motor and going to a 36V LiFePO4 battery pack (and upgrading the controller if I smoke it), can I get 20 - 25 MPH out of it with 20" tires, assuming it is just me at 200 lbs? I would stick to about 15 MPH when I have my son on with me... I also assume this means coming up with a cooling solution for the motor as well. This would be for running around the neighborhood, to Sonic, Walgreens, etc.
Option 2, higher cost errand runner:
(I had a 66cc 2 stroke bicycle that I used in this capacity, but it was a nonstop maintenance project until I blew the motor. I then sold off the parts and used the $ to restore a go-kart for my son)
If I go the high speed route I would like to be able to cruise at 35 - 40 MPH (errand running vehicle to Target and such, 5 miles round trip, 35 MPH backroads). I think I will have to get a bottom bracket crank extension for the pedals, but would like to retain them if possible. Using a gear ratio calculator, looks like I can hit those numbers easily with an 11T front sprocket, 44T rear, 20" tires and 3000rpm. So I was looking at the 1000W, 48V MY1020-B at tncscooters? How would take off torque be with something like that?
Or is the wheelbase too short for these kinds of speeds?
Option 3, staged upgrade:
Is it possible to reach my goals with option 2 using only 36V? If so, I can just upgrade the battery to a good 36V pack first, then cruise around at lower speeds until I get the time and $ to upgrade the motor, controller, sprockets, etc.
Thanks all!
