M.L. Toys
M.L. Toys
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I want to go faster.
By kilo_z71
First time poster here, but long time MPW troller. This post seems to cover a few different categories, but more speed seemed to be the overall theme. I've got two girls under 4, and a Kid Trax 6V Viper (Fwd & Rev only, one wheel drive). During a bored Saturday afternoon I wired up a 12V battery in it (I unplugged the circuit board as to not fry it) and my girls loved. I took it out because it wasn't done right, but just rigged up to see if they would like it, could handle it, and if the wiring, motor/gearbox would holdup. Now they pout because it goes slow and "will never go fast again!" So I'm looking to do it the right way now and seeing's how y'all are the experienced ones, I thought I'd run some stuff past you. So let me know what you think.

Getting rid of the 6V battery and getting a good 12V 18Ah, SLA battery to drop in with a fuse. Yes I know it won't fit, but a little fab work isn't a problem.

To keep the circuit board working (lights and sounds) I was going to get a voltage regulator to step down from 12V to 6V.

And since I'm going this far, I figured I might as well add a second motor/gearbox to reduce overall load on the motor/gearboxes, keep it from pulling to the left when they step on the gas, and because two wheel drive is cooler than one wheel drive. I know there isn't a provision for a second motor/gearbox stock, but I can work around it.

I figured the stock wiring probably won't like that much current flowing through it, so I'd get a few relays that would keep low current flowing through the stock wiring, and make the gear shifter drive the coils on the relays to control the motors forward and reverse(does anyone know how about how many amps a stock motor can pull at full load?).

Let me know your thoughts, things I'm missing, haven't thought of, or anything else. Thanks.

Unsure of your particular ride, but generally speaking, a 30 amp fuse is good. So if you get 30 amp relays, or better yet 40, you should be just fine. Best guess anything under that and your probably to close to risk welded contacts causing run away.
By kilo_z71
Thanks Suburbancharlie77. I was thinking something along those lines but good point you made about melting the contacts.

Here is a wiring diagram to more clearly represent what I was thinking. I'm more of a mechanical guy than electrical, so don't take this as gospel, and let me know your thoughts. Thanks.
Kid Trax Viper 6V to 12V Wiring Diagram.jpg
Kid Trax Viper 6V to 12V Wiring Diagram.jpg (65.4 KiB) Viewed 5120 times
I'm no wiz, but are you sure that you even need the relays? I was expecting something far more complicated.
I really can't imagine the shifter switches are much different than the power wheels ones, and there's only the 2 switches, and gas pedal, and has no problem with even 18 volts. I don't see why you wouldn't be able to simply split the power wires to the one motor to both? This weekend I'll have a closer look at power wheels wiring to double check, but I don't think there's anything separating them?
By kilo_z71
From what I read most people who use stock harnesses are using one motor. The way the stock wiring is set up, the current flows through the Fwd/Rev switch before splitting off to the motor. So with my double motor setup, doubling the current though the stock stuff is what I was concerned with. But maybe I'm too entrenched with Murphy.

metaprinter...I don't see where my short is, but again I'm no electrical engineer. I've color coded the diagram to trace thing a little better.
Kid Trax Viper 6V to 12V Wiring Diagram.jpg
Kid Trax Viper 6V to 12V Wiring Diagram.jpg (67.94 KiB) Viewed 5111 times
By Rob222
by adding a fwd/rev relay you will only protect the shifter contacts from the higher current. Your power switch and gas pedal will still see the higher current. But at only 12v all the relays may not be needed anyway.
Last edited by Rob222 on Sat Jun 25, 2016 7:16 am, edited 2 times in total.
By Csalemka
I have the Kid Trax Dodge Viper SRT (yellow, not sure if it's different than the newer Red one) and here is basically what the wiring looks like from stock maybe it will help. From this thread.
Also, I don't think it's entirely accurate. I've traced all the wires. Working on drawing the diagram myself but I'm a bit slower. Will post later this weekend. I threw in 12V battery into everything being stock ie switches, lights, etc and haven't burnt threw anything. Although since then I've replaced headlights, put in flashing LEDs on front and back and put them all on their own 12V. But the rest of the stock switches are still being utilized on 12V and haven't had any issues. Shifter working fine and gas pedal working fine.
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By kilo_z71
Csalemka - that is the diagram I started with, assuming it was right. However I did assume, so I'll go back and pin out the stock harness to check. So your lights (until your changed them), sounds, ect from the circuit board work fine on 12V? And are you running the stock single motor/gearbox?

Rob222 - A DPDT relay wouldn't do me any good, but if I got a DPDT manual switch that would be easier. I was just trying to make do with stuff I had on hand, but the ol' amazon has them for $15. But like you said, then that is the only thing being protected from the high current. The pedal wiring is stock, but again I'm taking someone's word for that, and will check it out myself.

Rob222 and metaprinter - This was based on the diagram Csalemka linked to. So I'll check it out and see, but assuming this is an exercise in wiring for now, I don't see where the short comes from (might just be my severe incompetence) . Both relay coils have +12V supplied when the power switch is closed. Assuming the shifter is in the shown position (forward), when the gas pedal is closed -12V will be supplied to the top shifter contact, which supplies -12V to the forward relay coil. -12V is also supplied to the bottom shifter contact, but since the switch is not closed to that contact, nothing happens. The forward relay will close, sending +12V and -12V to the motors. It will also send +12V and -12V to the output side of the reverse relay, but since it's not closed, nothing will happen. When the shifter is put in reverse, the 2nd from the top and bottom contacts are closed, which would send -12V to the reverse coil only.

With how my brain understands it, let me know if that's how it actually works or not (assuming the stock diagram was right, which I'll check out tonight). I know I should just throw an Ardunio in it and be done with it, because I'll probably do that later on, but I'm wanting to do it on the cheap for now. Hey happy Friday to everyone by the way.
By Csalemka
Not sure if you can understand it but here are the notes I took when tracing all the wires. Hopefully you can decipher it. I'm going to finalize the diagram this weekend and post what I got. I'll answer what I can about deciphering. Just want to share it hoping someone can come up with the schematic cause mine is probably going to look like crap. But it will be understandable haha.

Gas Pedal
- back to front bumper (black-blue-gray)
Black- to rear bundle, Blue- to Throttle 1, Gray- to Throttle 4
Large connector to dash
- Red big- to Throttle 4, Red small- to Small connector to dash, Gray- to rear bundle
Small connector to dash
- Red- to Large connector to dash, Black- to rear bundle
- lateral front to back 1-2-3
1. Black- to 6, Blue- to gas pedal
2. Black- to rear bundle
3. Red big- to 4, Red small- to front lights harness
- medial front to back 4-5-6
4. Red big 1- to Large connector to dash, Red big 2- to 3, Gray- to gas pedal
5. Red- to rear bundle
6. Black big- to 1, Black small- to front lights harness
Charging Port
- black, red, white to harness
- Harness output- small black x2, red, gray
- Distal end of harness output
Gray- to Large connector to dash
Red- to battery harness
Black small 1- to Small connector to dash
Black small 2- to battery harness
Motor Harness
- Black- to Throttle 2, Red- to Throttle 5
Battery harness starting at battery connector
- Black- to Gas pedal, Red- to charging port
Dash side of harnesses
- Large harness- Red 1- to power, Red 2- to power
Small harness- Red- to CPU, Black- to CPU
By Csalemka
kilo_z71 wrote:Csalemka - that is the diagram I started with, assuming it was right. However I did assume, so I'll go back and pin out the stock harness to check. So your lights (until your changed them), sounds, ect from the circuit board work fine on 12V? And are you running the stock single motor/gearbox
Yes, everything stock worked just fine on the 12V. And yes still running stock single motor & gearbox. Has a crazy amount of additional speed but definitely a lot more slipping on the road but it grabs and then goes. The wheels are about 2 years old so some wear and tear there as well. New tires might really help (or tear up the gear box). I am currently working on putting a 6V under the seat as well and installing a DPDT power wheel shifter switch so that I can switch between 6V & 12V. I have a 4 year old and 2 year old. 12 gets a little fast for the 2 yo.

Did a quick setup with stock harnesses and the following 6V/12V setup and it worked fine. Now I just have to mount the switch somewhere and do all the wiring again.
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By kilo_z71
Csalemka - The wiring diagram you linked to, and the one I started from are correct (except instead of a white wire as it says on the diagram, its a grey wire on the car). It's just the wiring diagram you linked to cleans up a lot of stuff that is wiring together in the car.

The gear shifter switch is a DPDT switch made for 125VAC 20A. So if you follow the DC current rule of thumb, it should be good to 30VDC 20A. The throttle switch is only rated for 6VDC 10A. So I'm still concerned about the current draw for my dual motor set up, but might try it for a while on one motor.

The different voltage switch is a cool idea for the different kids. My second one won't be driving for a while, so I'll have to look into that.
By kilo_z71
If they're working for now I'd leave them be, but I'd have a backup plan ready.

I just got the second motor/gearbox yesterday and had to go out of town this weekend for work. So I'll start on it next week and post some pics if you want.
By Csalemka
Most definitely. Post it up. Someone had recommended taking the kid Trax 12V police car Dodge Charger and somehow just retro fitting the whole rear end of the body. More or less. Hadn't really looked into it but going to once I got more of the current mods I'm already working on more solidified.
By kilo_z71
Ok, well finally got it mostly done, not too happy with how it looks, but my little girl won't know the difference, see the attached pictures.

I had to grind off the little tabs on the axle to allow the gear box to move farther in towards the center of the car. Then I propped up the new gear box and matched the vertical position with the left side gear box to make it look even. This allowed me to see where I needed to cut out under the driver seat to make everything fit. I had to cut out alot more than I thought under the seat to get the right side tire to stick out the same as the left side tire. I also cut out a big section in the middle for the new battery to fit in. Then roll a piece of sheet metal for the new motor to sit in, and cover up the rest of the gaps with more sheet metal.

I wired up the motors using the stock harness connector that split in to two Deutsch connectors, and the battery still uses the stock connector with an inline 30 amp fuse. This way I can put it back to stock if I sell it. I did use a voltage regulator to step down to 6V for the electronics board, and added an LED in dash so I know when the power button is on/off. Right now, the current is running through the stock wiring and switches. Things get warm to the touch, so I know I'll have to revisit that later (maybe with my relay setup). I also need to put some cooling fans in for the motors, but all the ones I have right now are too big, so another thing I'll have to revisit.

I did measure the RPM difference in the new and old motor/gearbox outputs. They are close (with in a few RPM) of each other, so that shouldn't matter.

Here are some specs for this car, for general information.
Motor has 10 tooth pinion
Gear box - 20.5:1 reduction
Tire (no load) RPM and MPH at 6V - 100RPM, 17MPH
Tire (no load) RPM and MPH at 12V - 215RPM, 36MPH
*Those are no load measurements (car propped up, no drag on tires). The car doesn't really go that fast. Assuming the manufacture top speed of 2.5MPH, that's about a 15% efficiency.
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I'm not sure how you calculated the speeds, but I'm hoping those are wrong, for kid safety!
One thing about the sla batteries, they can be discharged in any position, but best to be charged in an upright position.
By kilo_z71
The no-load speed is easy to calculate once you know the tire RPM, and circumference. But as I said, those speeds are at no-load. When the kid sits down in the car it loads the motor/gearboxes and the car won't go near that fast. That's what I was saying about the 17% efficiency...assuming the 2.5 MPH manufacture top speed claim, the car only goes 17% of that no-load speed.

I haven't yet, but will get an actual speed on the car, with a kid driving it, soon to see how close that top speed really is.
By Csalemka
Want an update! I know this is a year old. I haven't touched the kids ride ons since last year. Finishing school, baby #3 and such. Where did u get the motor? Are you using all of the stock harnessing/wiring? Is it all still hooked to the charging port on the side of the vehicle? Does it work since the stock battery is 6V and I'm pretty sure there's something in that charging port that only allows charging of a 6V because the stock port shuts off the battery from the throttle I believe so it can't be run while plugged in. Would love an update

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