Hunting Kart Controller / Motor help

[loves80z]

Hi all,

I am looking for help with a motor and controller combo. I posted on another forum, but have not gotten any response and I have read a lot here so am hoping to have some discussion/help.

I have built a kart. Some pics attached. I need an upgrade for more power (go figure) and a better controller. The kart goes thru mud on my hunting property carrying 200 lbs of cargo and weighing 300lbs and dragging materials at walking speed. Its geared so 3600 rpm is about 4mph. The motor I am running now is a 1kW MY1020 brushed and a $30 controller. I keep destroying the controllers. The contacts on the relay weld shut and I lose reverse. I took the controllers apart and found the relays are rated 20 amps NC and 30 amps NO. The kart paddles thru the mud slow. I can see its pulling upper 20's for amps when its doing it. The mud is in patches. At this point I figure that the motor has been overheated exceeding duty cycle and the controllers are not sufficient either so the current system has got to go.

I would not mind spending more money on a better built motor and controller and over sizing things so they run cooler when I'm pushing hard. With the cart going slow and everything inside the body, I am not getting any cooling from air movement.

I have looked for a better motor but having a hard time of it. The 2kW range doesn't seem to have much for good motors so I have been looking bigger. Without any better ideas, I am thinking I will get a lightning rods big block and a Kelly KLS6018N. I am running 4 marine 90amp hour batteries. I don't think I have room for a 5th battery, but I could change to 60v when those batteries life is up. I bought them last year. I am not stuck on Kelly controllers, I just don't know any better and I figure I will need to program temperature and max amps drawn. Also feels like using a controller that works in torque mode would be best, but again I don't know any better. What does everyone else think?

Do the Kelly sinusoidal controllers work well with the LR motors? Does anyone have another controller/motor combo that may be a better fit for the job?

Any help would be much appreciated.




Thank you.
Kevin

 

[amberwolf]

If you go to a brushless motor and controller, there won't be a need for a relay to do reverse, as the electronics in the controller will operate as well one way as the other.


There are brushless versions of motors in the same basic design as that MY-motor, including some that have similiar model numbers, so they would essentially be a bolt-on replacement. Then a brushless controller that can do the current you're after.

If the motor itself is not large enough for your needs, you can get bigger ones. QSmotor makes a similarly shaped motor that I think is rated for 3kw (there's a few threads that discuss them; might be called a QS120? cna't remember).

If the motor and controller are buried inside the casing, you should add forced ventilation to keep them cool.


Don't know which controller would be best; depends on the features you need, power level, voltage, etc.


But the first thing I would recommend doing is ditching the lead batteries. You could cut 3/4 of the weight off that battery pack, and greatly reduce the power needed to move it by doing that. Each of those batteries probably weighs 60lbs, so you would be taking 180lbs off the cart.

Also, because you don't generally get anywhere near the rated capacity from lead batteries, vs lithium, then you wouldn't need as many Ah either. So the battery will likely end up even smaller and lighter. Without knowing how much capacity you actually use now, I couldn't say what you'd really need, but I would guess that 50-60Ah of Lithium will probably be equal to the 90Ah of lead, for usable capacity. Might need more, probably not.

You could get used Nissan Leaf cells that just bolt together; not sure of the cost; there's various threads about those. Other cells also available, some bolt together, some requiring more DIY methods. Some new, some used. etc.

 

[loves80z]

Thank you for the response Amberwolf. I will be looking for information on the qs motor. From their website that looks like a good recommendation I have not seen before. I am not limited to the size / shape of the my1020. I will make whatever mounting I need and I do have more space.

Good suggestion on cooling with forced air. I could use a thermostat controlled fan.

I don't think budget will allow me to ditch the lead batteries and buy lithium. You bring up good points though. Less power required because of less weight. I paid 100 per battery so thats 400 total for lead. I will have to take a second look at it. Wishing I had asked for advice last year.

Thanks again!

 

[loves80z]

I asked Fany at Kelly controller for a recommendation. The recommendation was for a KLS7218S, It can be configured for torque, current or RPM mode before shipping. Current mode is when the controller adjusts motor current according to throttle and that's what I think I want.

 

[loves80z]

I purchased a 2500w boma motor and a KLS7230S. Hoping the Kelly autotunes the motor.