Fitting 250w setup to 12v kids quad??

Vr6woes

As above really,

Had the quad for nearly two years now, had a 12v car battery fitted which extended run times immeasurably.

Sadly it is no longer fast enough hence this project.

I’ve cobbled together a list of bits and have had a decent go at getting them together however I’m stuck and would greatfully take some advice at this point.

So. I bought a 250w speed controller. Below is the model.

I got this throttle.

I’ve wired two 30amp 12v lead acid batteries in series and done my best with the throttle and switch wiring. I used the original push on/off switch from the quad. It had two positive and one earth tab so I wired the plug labeled ‘power lock’ to this switch as well as the yellow wire from the throttle to the spare positive terminal. The other 3 wires from the throttle are wired to the plug labeled ‘dérailleur’

Controller. Throttle

Blue green

Red red

Black blue

So. The switch turns on and off. And the led volt gauge on the throttle turns on and off with the switch so I thoufh here we go, easy as that.

Unfortunately not. When I connect the motors they are stuck on at wide open throttle. Even with the throttle pins disconnected. Throttle has no effect on motor speed its just full throttle soon as the battery is connected.

Can’t figure out what I’ve done wrong or is there some way of checking if its just a defective controller it was only 9quid off ebay so won’t be the best.

Any advice would be welcome.

Thanks in advance.

Max

justin

Vr6woes Very cool project. Here are my thoughts:

Behavior of the speed controller doesn’t sound that unusual. A lot of electronics will exhibit unusual behavior when you have open circuit and input (throttle pins) are left floating.

Typically the throttle control will get 0-5V from the speed controller and supply back 0 to ~ 3.5-4V over a third pin that tells the speed controller throttle position. 0V would correspond to off and 3.5 to 4V would correspond to max throttle.

I searched Amazon for this product and found this writing diagram. Not sure if it’s exactly what you have.

To rule out issues with the speed controller, try shorting the 0V pin on the throttle connector (Speed adjustment in this diagram) to the throttle speed input (Signal input pin). This should put the motor at 0% throttle and verify that something is not messed up with the speed controller. If this works, good sign that you have the right pins/connectors and that the speed controller isn’t stuck at max throttle. When you unshort the pin, I’d expect it to go back to wide open throttle b/c that sounds like the behavior of the controller when the throttle input is left floating.

Before connecting up anything though, I’d double. check that you are working on the right pins/connectors. Best way to do this is with the supplied sheet + verify voltages using multimeter in voltage measurement mode if you have one.

If that goes well, second thing I would look at is the throttle control. Verify that you have the correct pinout (0V, +5V, Signal output). You should be able to connect the throttle to 0V and +5V, then monitor the signal voltage output using a multimeter. You’ll connect one pin of the multimeter to 0V and the other to the signal output pin on throttle.

As you twist the throttle, you should see the voltage on the multimeter going from 0V up to whatever the max voltage is. If you aren’t getting that, then either you pinout is incorrect, you have connected something incorrectly, or the throttle is broken.

Caveat with using the multimeter: make sure you are operating in voltage and not current mode. If you make the measurements described above in current mode, you’ll just blow out fuses on the multimeter and wonder why it’s not working correctly.

Hope this helps! Please update us on your progress.

Vr6woes

Mate,

Thank you for a quick reply, much appreciated.

I have done the initial test you recommended, made up a jump lead and bridged 0v, black wire with blue signal wire, still WOT. So is it possible ive fried it with connecting it up in a myriad of different, incorrect ways? Or a duff controller, at 15quid I can’t imagine the QC is up to much.

Haven’t got a multimeter and had a feeling this project was going to need one, ill get one anyway but do you think its wise to order a new controller? Is there any other quick check i could do to confirm the controller has had it. All components were brand new but I’ve bought enough chinese stuff to know that doesn’t really mean anything. Thsnks again.

justin

Vr6woes I would at least get a multimeter (they are pretty cheap) and make some voltage measurements to make sure everything is looking good and connected as you think. It’s definitely possible the controller got fried or sent you a faulty one.

Vr6woes

justin

Hi mate, thanks for getting back to me.

Update, ive got a multimeter and also bought another speed controller assuming the first was duff.

Unfortunately same issue as the first.

Using multimeter im getting 24+v out of the motor wires the second batteries are connected. Regardless of whether throttle or anything is connected. I’ve bridged the 0v negative to signal wire and has no effect, still WOT as soon as battery is connected.

Controller must be working to an extent as ive got yellow wire from throttle connected to positive terminal on switch and when turned on throttle illuminates and displays voltage and turns off when switch is pressed. However, regardless of pin out configuration nothing has any effect on motors which are always at wide open throttle with batteries connected.

I’m starting to think I’m making some basic error in connecting this up, possibly with the battery to motor circuit as you can have everything disconnected just motor and battery and full power and even bridging the throttle input pins to 0v to signal wire still getting full power.

I’m usually pretty good with electrics, at least simple stuff like this so very annoying I can’t get this sorted. Any help is again much appreciated.

I’m ruling out defective speed controllers as chance of getting two duff ones on the bounce is pretty slim

Hope you can help, im too invested now to abandon the idea, cant let the daughter down, lol.

justin

Vr6woes I’m sure you can get it to work!

I took a quick look through the comments on this Amazon listing (seems to be what you have) and someone said throttle input range was 1V to 4.5V for control. If this the case I’m a bit surprised that connecting input to 0V wouldn’t work.

One thing you might test is the throttle output voltage at 0% to 100% throttle and see what range that is giving.

I looked through your photos carefully and it’s a bit difficult to tell what’s connected to what. Best way to help is if you could pencil out how you have things connected.

Vr6woes

Quick update guys.

Cracked it. Turns out the throttle just wasn’t compatible with the speed controller. Bought a new one with integrated key switch, wired it up exactly as I had done before and it worked instantly.

Still running the wrong motors, 18k 12v. Previously running off the original wiring these motors didn’t have the torque to even drive the thing with a kid on it.

Same motors with new speed controller and it is slightly faster than stock. I have a pair of 24v motors on route. These come with gearboxs attached. These 24v gearbox have a few internal metal gears and way more torque than the ones in it now so should be perfect.

The linear throttle is brilliant. Just got to find a way of hiding or covering the front battery. But the concept works just need to fine tune it all now.

justin

Vr6woes Congrats on the progress! Throw up some photos of your finished build when you have it all together.