M.L. Toys
M.L. Toys
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Need new batteries? Going from 12V to 18V or 6V to 12V? Wiring Questions?
By MathewB
Good afternoon,
I'll probably get burned for even thinking this all up so don't hold back. I've currently got a power wheels dune racer runing on a porter cable 5 AH 20v battery with 775 traxxas motors and steel first gears + pinions from MLToys. I decided to go one step further and wire in a SPDT 30/40 amp waterproof relay with a steering wheel mounted momentary push button (Boost) switch. when activated, it ties a second 20v battery in series with the first to create 40v. Now, this is not a great solution nor do i plan to keep it long term. I do not have a speed controller and i'm using stock wiring/switches (pedal and shifter). I did install a waterproof fusible link on the positive of the batteries (30A) for safety. As i'm sure you can imagine i've blown the fuse a couple times. I have 3 girls, one is 9 (63 lbs) one is 7 (60 lbs) and one is 5 (58 lbs). they like to ride solo though they do occasionally ride together, Thus the blown fuse. That being said, the car runs great and it's fast (scary fast O.O) i did the bike tire mod to the front though i don't dare do anything to the rears (Shredding the gear box and melting motors).

All that said, i'm thinking about doing an overhaul to the entire power wheels to include:
- 10 AUG Wiring for the entire Car
- Mini timer time delay relay for the boost (5 second on, 10 seconds 0ff)
- Triple relay parallel to series battery system ( 2 matched batteries in parallel that switch to series when boost is activated
- LED headlights and tail lights
- Remote kill switch (thought about the legitimacy of an RC speed controller wired up in reverse. Pull the controller trigger to kill the voltage at variable speed)
- Change out front wheels for actual air inflated rubber tires and rims.
- Change to Brushless motors (Is it worth it?)

I've also sourced a means for mounting the lithium ion batteries in the vehicle though it would be expesive. Plan is to use modified Dewalt Tool Connect adapters hard mounted and hard wired into powerwheels for easy connect/disconnect and possible tracking? This of course would mean using much more expensive dewalt li-Ion batteries. I'm not interested in Lead acid. I'm planning to draft up a drawing for the electrical stuff but could use inputs. I'm not sure about the logistics of the front wheel modifications and how intensive that process would be. Not sure how much an RC motor controller can take (volts and amps) Anything helps, but i'm really excited about the project and i know the girls are stoked. All the neighbor kids are jealous of their power wheels :P and i've got some of the dad's asking about doing modifications themselves. I understand this is dangerous and i know the motors are only rated to 18.6V, i know the wires get hot. I want to do it right, but i also don't want to spend $2000. I realize i could just buy an electric go kart but that takes all the fun out of experimenting and all the curiosity out of the kids (switch and relays and batteries are a cool learning experience for kids). Let me know what you guys think. Thanks in advance.

Mathew B.

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By Hammer-fm
Speed is addictive, isn't it? The ESC is the most important upgrade, as even with a 2-speed (turbo/non-turbo) option, with those kind of speeds it is nice to have the finer control.

If you have an ESC you don't need the parallel vs. series relay. It's easier to build in a throttle-limiter option so that "full throttle" becomes 50% duty cycle (this can be typically done with two resistors on the throttle return line and a low-current switch).

40V on that Traxxas motor is probably going to be fairly short-lived, owing to very high brush speeds as well as excessive heat at high RPM. I think you already guessed that, so the second question would be to look at options. MHO, the right option for that much speed is to either do scooter motors and a chain drive, or dual motors (and skip 1st gear) -- both of which require some fabrication. The gearboxes in my vehicles with the dual-motor setup (see link in my sig) have been problem-free for over a year, even at 3x stock speed, and even with increased traction vs. stock. Since they're each running only 18V and ~22-23k RPM, they're not being worked that hard. See an example video here. Without the speed controller it was really unusable above 24V (see the end of this video). You at least have a turbo button :lol: .

You could move to using a gearbox with a higher tooth count (eg. get a Corvette gearbox and drill out the axle hole). You could put a 22T gear on and get a 38% speed boost vs. the 16T. Running that 20V will still be pretty quick and would last a lot longer than 40V. Maybe not fast enough though...
dual-motors.jpg (48.94 KiB) Viewed 2683 times
By shender944
Im running a 36v lithium ion setup the battery came from a hover board. I then ordered a speed controller and throttle pedal from an online scooter store. Originally I ran the back two motors in series to keep the voltage down to 18v but it only lasted about a month. Im now in the process of converting the car over to rubber tires from harbor fright and a straight axl chain drive powered by a 500w motor. Well see how things go i might upgrade the motor if I recall correctly the speed controller is good for up to 1000w.
By MathewB
Due to the nature of my work I travel a lot and I've been benched on my projects. Lots of birthdays and holiday stuff around the corner so money is tight, However I am seriously intrigued by the quad motor design (2 motors per gear box) I think a good power controller and the quad motor design would be perfect for a simpler build-out that gets the job done and done well. I did end up burning out one of the Traxxas 775 motors as was expected.... told the girls they can't use the boost button in the grass or when riding together (Just another reason why I really want to do this modification) I've always had a fascination with EVs and that translates into a more affordable hobby of electric ride on vehicles.... XD The 5 AH batteries i'm using are off brand porter cable and they're not holding up very well on their own so i bought new ones and put them in series with a much smaller boost battery on the other leg of the relay. I think ideally I would have 2 sets of 2 x 5 AH 20v batteries in parallel and a good power controller with a decent Hall-effect pedal. Still considering brushless motors if that isn't totally irrational and i've even considered more elaborate redesign to include fabricating an aluminum frame and replacing rear axle to accommodate a scooter motor and chain drive. Ideally the power wheels will look stock but run quite fast. My short term goal is to make the dune racer faster than the neighbor kids on their bikes.... I'm close XD. I'm going to try and follow this forum better and i'll take pictures and maybe post a video when I've done some serious remodeling. Thank you for the valuable insight and I look forward to talking with you more about this project.

Shender944 - That definitely sounds like a viable option as well. I've looked on or something like that and sourced a 2000w power controller with a hall effect pedal for about $100. I figured i would leave room for improvement though i don't know what i could possibly do to get 2000w through a power wheels O.O or if that could even be done responsibly to any degree. I am interested to hear how your project turns out.

Thanks for the input, I'll keep you guys updated as I make progress.


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