Kelly Controller not sending voltage to throttle

SS_denver

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Mar 30, 2025
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Denver
Hey all,

I am helping my nephew with an Ebike build, and he is having issues with his Kelly Controller (model Mini KVD8420NV). We have successfully hooked up the the battery and throttle to the controller, but get no results from the motor. When I probe the output from the controller with a voltmeter there is no voltage coming from the controller. Could we have blown a fuse in the controller when hooking up the battery? Is it possible the controller is defective?

Any help would be greatly appreciated. Thank you!
 
Not sure I follow.

I'm running power to the controller from the 48V battery, which has a line to the throttle that I assumed would be delivering 5V (and then the throttle acting as a pot to deliver control signal back to controller). Is that not correct?
 
Did you wire power to the ignition line?
DJ7091Y-2.3-11 Pin Definition
(14) REV_SW: Reverse switch input. Orange
(6) RTN: Signal return or power supply return. Black
(12) FWD: Forward switch or High speed switch White
(11) 12V:12V Source Red
(25) 12V brake switch. Yellowish
(22) ECO: Low speed switch input Blue
(33)CAN-H:Greenish(Optional function)
(7) PWR: Controller power supply (input). Pink
(34)CAN-L:Brownish(Optional function)
DJ7091Y-2.3-21 Pin Definition
(15) Micro_SW: Throttle switch input. Gray
(3) Throttle: Throttle analog input, 0-5V. Dark Green
(1) Temp: Motor temperature sensor input. Raddle
(20) RTN: Signal return. Black
(8) Meter: Copy signal of hall sensors. Dark Gray
(4) 5V: 5V supply output, <40mA. Purple
(2) Brake_AN:Brake variable regen or Boost function. Brown
DJ7061Y-2.3-21 Pin Definition
(21) RTN:Signal return. Black
(5) 5V: 5V supply output,<40mA.Purple
(18) Hall A: Hall phase A. Yellow
(17) Hall B: Hall phase B. Dark Green
(16) Hall C: Hall phase C. Dark Blue

Think - ignition line = (7) PWR: Controller power supply (input). Pink

This be the wire that makes controller turn on.
 
Ok....I think I see where the disconnect is. When I talked with my nephew about this he said that the three connections from the controller were for 1.) a throttle. 2.) a motor and 3.) a volt-meter of some type. He said we didn't need the volt-meter and that we were just going to throttle and motor it, but clearly we need to power pin 7 using this third connection.

Is there a recommended piece of hardware I can buy to connect to this last connection (the volt-meter...or whatever it is we are missing)? BTW, below is the wiring we've done so far. everything seems so straight forward I am at a loss as to how we screwed it up (though it wouldn't be the first time.)

controller_screenshot.jpg
 
Normally a switch or keyswitch is used to connect the ignition / ksi wire to the battery positive.

Depending on the controller design, if you have a separate switch to turn your system on and off at the battery, you can wire that directly, with no switch. Doing so will mean that if your system is connected to the battery, the controller is active, and any throttle input will engage the motor, with no safety interlock.

A switch on the handlebars between the wire and b+ gives you something to turn off if the throttle input is stuck at some voltage above the zero point (broken ground wire, etc).

Some controllers (including some kellys) require a precharge and a contactor to switch battery power to the controller on and off, *after* the ignition wire is connected to the battery, to power the controller's insides on and off in the right order. Check your specific model's manual (from the kellycontrollers site) for the wiring diagram for your version and the type of setup.

If the controller isn't powered up in the right order, it may just error out and not operate.
 
Ok, that makes sense actually. Otherwise the controller is just always on (somebody bumps the throttle and it could drive off!)

I think I'll buy an ignition to hook up to the Kelly controller...probably stick with Kelly brand just to make sure that everything is compatible (at least to minimize the headaches...trying to keep this kid excited about building things). Do you all think that if I hook up the ignition that I've linked below that I'll be able to get this puppy moving?


Thanks for all the help BTW!
 
Depends on the model; if it's like any of those I've seen or had in my hands, you'll have to connect it to the computer to setup the motor with it.

Check your manual for that specific model and version for the specific wiring you need (including contactors, precharge, etc), and for the procedure(s) for setting up the controller to run on your specific system.


They may have "plug-and-play" dumb controllers that don't require that, but then you have to figrure out the hall/phase combination manually. (there are threads for that).

As for "brands" of keyswitches....it doesn't matter. You just need a switch that closes it's contacts in one position, and opens them in the other. The one you link is going to require you to figure out it's wiring and make connectors to match your setup; the same is true of probably all of them.

Pick one that mounts where you want it, works the way you want it to, and has any other features you like (voltmeter, mode switches, waterproofing, requires key to stay in to stay on, etc).
 
The voltmeter+throttle will work just fine. It says Kelly style plug it doesn't really say if it's pinned correctly or plug and play. It's not hard to take the pins out and repin the plug so it shouldn't be a big deal. I have quite a bit of experience with these controllers, if you need anything just send me a PM.
 
PM is the fastest way to get help from me since I don't check in to this forum as frequently as I used to. Not to mention that most people don't use the search function anyways.
 
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