Rawdawg697
New here
First post here and don’t really know much about anything EV related. I’ve worked on cars/trucks/dirt bikes my entire life and have no problem with the design or modifications regarding my new project, other than the electrical components.
I found a good deal on an old electric rental go kart and bought it. The seller of course told me it worked fine just needed new batteries. Once I got home and started cleaning and inspecting things I discover the controller was shot. Pulled the controllers pcb (if that’s what it’s even called) out of the housing and found a giant burn hole through it and the thick copper bar running through it.
With the controller shot and what I believe to be suitable replacements for high amp brushed controllers being very expensive while not know if the motor was shot too, I started digging into it. The motor is a lynch motors lem-200 48v 200 rated/ 400 peak amp motor. Not having any batteries besides a bunch of 3s rc batteries and Milwaukee m18 batteries, I decided to rig up 2 m18 batteries and connect them to a kill switch and directly to the motor, the motor spun up and sounded fine with the tires off the ground. I jumped in and turned it on and ripped around the neighborhood did some donuts and realized I was melting the thin wire I used to rig up my batteries so I quickly shut it off.
Now to my questions/help needed/recommendations
Most of the brushed controllers I looked at that could push over 200amps were several hundred dollars so I assume I’d be better off switching to a brushless motor and controller?
I’d love to go crazy with the build but I want to keep the build relatively cheap while still being pretty powerful. I started looking at the kr5v motor but haven’t found to much details on that motor. I’ve watched countless videos on YouTube of qs138 motors in go karts and that looks like a lot of fun but I definitely don’t need to be doing 80-100mph. Would a qs120 be a decent motor in a go kart?
Moving on to batteries I obviously don’t think my rc batteries or m18 batteries would be suitable long term so I’ve been playing with the idea of building my own possibly out of A123 cells or maybe 18650/21700 cells? Then I can found the 44v Honda clarity batteries that are like $60, I could get 2 of those for dirt cheap and put on a nice bms. Could I run one 24s bms for two Honda clarity modules or would each 12s module need its own bms?
I’d love any recommendations or guidance on this project because like I said I really don’t know anything about the ev components.
I found a good deal on an old electric rental go kart and bought it. The seller of course told me it worked fine just needed new batteries. Once I got home and started cleaning and inspecting things I discover the controller was shot. Pulled the controllers pcb (if that’s what it’s even called) out of the housing and found a giant burn hole through it and the thick copper bar running through it.
With the controller shot and what I believe to be suitable replacements for high amp brushed controllers being very expensive while not know if the motor was shot too, I started digging into it. The motor is a lynch motors lem-200 48v 200 rated/ 400 peak amp motor. Not having any batteries besides a bunch of 3s rc batteries and Milwaukee m18 batteries, I decided to rig up 2 m18 batteries and connect them to a kill switch and directly to the motor, the motor spun up and sounded fine with the tires off the ground. I jumped in and turned it on and ripped around the neighborhood did some donuts and realized I was melting the thin wire I used to rig up my batteries so I quickly shut it off.
Now to my questions/help needed/recommendations
Most of the brushed controllers I looked at that could push over 200amps were several hundred dollars so I assume I’d be better off switching to a brushless motor and controller?
I’d love to go crazy with the build but I want to keep the build relatively cheap while still being pretty powerful. I started looking at the kr5v motor but haven’t found to much details on that motor. I’ve watched countless videos on YouTube of qs138 motors in go karts and that looks like a lot of fun but I definitely don’t need to be doing 80-100mph. Would a qs120 be a decent motor in a go kart?
Moving on to batteries I obviously don’t think my rc batteries or m18 batteries would be suitable long term so I’ve been playing with the idea of building my own possibly out of A123 cells or maybe 18650/21700 cells? Then I can found the 44v Honda clarity batteries that are like $60, I could get 2 of those for dirt cheap and put on a nice bms. Could I run one 24s bms for two Honda clarity modules or would each 12s module need its own bms?
I’d love any recommendations or guidance on this project because like I said I really don’t know anything about the ev components.
It *could* be fixed, and if it were in my own system then in my younger days I would have done so, but these days I'd pass. 
