OK, maybe not quite as crazy as the laser cutter I started over 2 years ago and oly finished a little while back (or almost finished), but this sounded like so much fun I couldn't resist 
Basically, I'm starting off with one of these:
It's brand new, and comes stock with 2 ridiculously heavy 7Ah SLA's, a shitty 200W brushmotor and a lame single speed throttle. But who cares about that, it's the frame I want
I figured, being an electric scooter already, it would be a good candidate for modding to higher power levels.
So, after purchasing the scooter, seeing how gutless it was (For me, anyway ), I began looking at a way of upgrading it.
I decided to use these:
3x 6S 5000mAh Turnigy LiPo's
A Turnigy Aerodrive SK3 - 6364-245kv Brushless Outrunner Motor
HobbyKing ECO6-10 200W charger
BAC-0283P brushless e-bike controller
Stock, the scooter has 2 12V 7Ah SLA's in series for 24V 7Ah, and a 200W brushmotor. Unfortunately Razor seem to have cheaped out over the last few years, as originally these used to have proportional throttles.
This is a shame because it means I have to purchase a seperate, proportional throttle to use with the new controller. Luckily the handlebars are a standard size, so they are very common, around $18 for a thumb throttle from China. I have decided to use a thumb throttle, just because it's not quite as easy to accidentally activate, and with this kid of power you really don't want it trying to take off without anyone on it.
The motor I am going to use is rated at 2700W peak, which is an insane amount of power, in fact with the scooters 5:1 gear ratio and ~25cm dia wheels, I calculated a max acceleration of 6m/s/s, which is insane and impractical. Because I also knew the ratios, I chose the 245kv motor based on the maximum speed it'll be able to run, which is around 49km/h. I will probably limit this to around 40km/h max, as it has short coupled steering so would probably have stability issues at such high speeds, not to mention dangerous.
However, the controller I chose was mainly based on available space. I really wanted to try keep everything nice and protected inside the original battery compartment:
So I printed out some to-size paper mockups of the batteries and controller, so I could do a test fit before purchasing, which helped greatly:
But, this controller is only good for 24V at 50A peak, so I would only be running the motor at around 1/3 capacity at most, which on this scooter, should still be more than enough. By overrating the motor, I shouldn't have too much of an issue with overheating, as the motor is fairly well out of the way of any decent airflow. It also means if I really need to, I could modify the controller, either by adding more or changing the FET's, and also adjusting the shunt to "trick" it into driving more power. But, like I said, the 1000W peak should still be more than enough for this.
So earlier this week I ordered the motor, 2 LiPo's and the charger, which are on the way at the moment. Hopefully next week sometime I can order the controller.
However, there are still a few things left to do.
Firstly, the motor comes with a 10mm prop adapter, which I need to turn down 8mm, thread, and mill/gring/file in a D key so I can attach the original sprocket.
Second, I also need to design kind of a "bridging" controller, that'll look after everything. It'll just be a basic uC, with a current shunt to measure total system power as well as regen braking, it'll also be able to program the motor controller "on the fly", so to speak, to limit both speed and current so that people lighter than me can also use it safely if needed, provide an LCD readout, of things like battery voltages, estimated run time, power consumption, regen braking power, motor & battery temps etc. So it'll kind of be the central processor, mostly for safety in monitoring the batteries. The same PCB will also have 3 connectors (Well, 6 including the balance connectors) which will act as the main battery "bus", and all the batteries will be charged in parallel off the 10A charger.
I like making threads on my projects as they're a convenient place to make logs until I have the time and effort to compile them on my site, and well, maybe someone else will be interested
Cheers,
Dan
Basically, I'm starting off with one of these:
It's brand new, and comes stock with 2 ridiculously heavy 7Ah SLA's, a shitty 200W brushmotor and a lame single speed throttle. But who cares about that, it's the frame I want
I figured, being an electric scooter already, it would be a good candidate for modding to higher power levels.
So, after purchasing the scooter, seeing how gutless it was (For me, anyway
), I began looking at a way of upgrading it. I decided to use these:
3x 6S 5000mAh Turnigy LiPo's
A Turnigy Aerodrive SK3 - 6364-245kv Brushless Outrunner Motor
HobbyKing ECO6-10 200W charger
BAC-0283P brushless e-bike controller
Stock, the scooter has 2 12V 7Ah SLA's in series for 24V 7Ah, and a 200W brushmotor. Unfortunately Razor seem to have cheaped out over the last few years, as originally these used to have proportional throttles.
This is a shame because it means I have to purchase a seperate, proportional throttle to use with the new controller. Luckily the handlebars are a standard size, so they are very common, around $18 for a thumb throttle from China. I have decided to use a thumb throttle, just because it's not quite as easy to accidentally activate, and with this kid of power you really don't want it trying to take off without anyone on it.
The motor I am going to use is rated at 2700W peak, which is an insane amount of power, in fact with the scooters 5:1 gear ratio and ~25cm dia wheels, I calculated a max acceleration of 6m/s/s, which is insane and impractical. Because I also knew the ratios, I chose the 245kv motor based on the maximum speed it'll be able to run, which is around 49km/h. I will probably limit this to around 40km/h max, as it has short coupled steering so would probably have stability issues at such high speeds, not to mention dangerous.
However, the controller I chose was mainly based on available space. I really wanted to try keep everything nice and protected inside the original battery compartment:
So I printed out some to-size paper mockups of the batteries and controller, so I could do a test fit before purchasing, which helped greatly:
But, this controller is only good for 24V at 50A peak, so I would only be running the motor at around 1/3 capacity at most, which on this scooter, should still be more than enough. By overrating the motor, I shouldn't have too much of an issue with overheating, as the motor is fairly well out of the way of any decent airflow. It also means if I really need to, I could modify the controller, either by adding more or changing the FET's, and also adjusting the shunt to "trick" it into driving more power. But, like I said, the 1000W peak should still be more than enough for this.
So earlier this week I ordered the motor, 2 LiPo's and the charger, which are on the way at the moment. Hopefully next week sometime I can order the controller.
However, there are still a few things left to do.
Firstly, the motor comes with a 10mm prop adapter, which I need to turn down 8mm, thread, and mill/gring/file in a D key so I can attach the original sprocket.
Second, I also need to design kind of a "bridging" controller, that'll look after everything. It'll just be a basic uC, with a current shunt to measure total system power as well as regen braking, it'll also be able to program the motor controller "on the fly", so to speak, to limit both speed and current so that people lighter than me can also use it safely if needed, provide an LCD readout, of things like battery voltages, estimated run time, power consumption, regen braking power, motor & battery temps etc. So it'll kind of be the central processor, mostly for safety in monitoring the batteries. The same PCB will also have 3 connectors (Well, 6 including the balance connectors) which will act as the main battery "bus", and all the batteries will be charged in parallel off the 10A charger.
I like making threads on my projects as they're a convenient place to make logs until I have the time and effort to compile them on my site, and well, maybe someone else will be interested
Cheers,
Dan
