Dual Kelly KLS7230SR + two 48V 1000W brushless motors for skid-steer UGV build

[belltozar]

Hi everyone,

I am planning to build a small skid-steer / tank-drive UGV platform using two Kelly controllers and two brushless motors. I would appreciate advice from people who have experience with Kelly KLS controllers, electric trikes, go-karts, or dual-motor EV builds.

Current hardware:

• 2 × Kelly KLS7230SR controllers
  • 24–72V
  • 300A
  • STD version
• 2 × electric rickshaw brushless motors
  • nominal voltage: 48V DC
  • output power: 1000W
  • rated speed: 410 rpm
  • rated current: 28A
  • chain drive output

The idea is to build a differential-drive UGV:

• left motor → left Kelly controller
• right motor → right Kelly controller
• steering by different speeds of left/right motors
• possibly controlled by STM32

The main questions I have:

1. What is the recommended power wiring architecture for two Kelly KLS controllers from one battery pack?

My current idea is:

Battery +
→ main DC fuse
→ manual disconnect
→ precharge circuit
→ main DC contactor
→ positive busbar
→ separate fuse for left Kelly
→ separate fuse for right Kelly

Battery -
→ negative busbar
→ both Kelly B- terminals

Does this look correct?

1. Should I use one main contactor for both controllers, or one contactor per controller?
2. What fuse ratings would you recommend for this setup?
   The motors are only 48V 1000W / 28A rated, but the Kelly KLS7230SR controllers are much more powerful. I plan to limit the battery current and motor current in the Kelly software.
3. For precharge, is it enough to use one precharge circuit across the main contactor before the positive busbar, or should each controller have its own precharge circuit?
4. For control, what is the best approach?

Option A:

• Use Kelly joystick / wig-wag mode
• 2.5V = stop
• higher than 2.5V = forward
• lower than 2.5V = reverse
• STM32 generates two analog 0–5V signals, one for each controller

Option B:

• Use normal throttle 0–5V
• Use FWD/REV digital inputs separately for direction

Which method is more reliable for a skid-steer UGV?

1. Are there any special Kelly KLS parameters I should pay attention to for low-speed, high-torque UGV use?

For example:

• battery current limit
• motor current limit
• acceleration time
• reverse speed limit
• joystick dead zone
• regen braking
• identification angle procedure
• thermal protection

1. Do these rickshaw motors seem suitable for this type of platform, assuming I keep the current limits reasonable and use proper gearing?
2. What common mistakes should I avoid when wiring two Kelly controllers in one vehicle?

I am especially concerned about:

• precharge
• contactor wiring
• fuse selection
• shared battery ground / busbars
• throttle signal grounding
• cooling of the Kelly controllers
• Hall sensor wiring
• safe emergency stop

I attached photos of the motor label and one of the Kelly controllers.

Any advice, example wiring diagrams, or links to similar dual Kelly / dual motor builds would be very helpful.
I am mainly looking for practical wiring examples: battery, fuse, contactor, precharge, busbars, two Kelly controllers, two motors, and control signal wiring.
Thanks!