Anyone want to help modify a Radio Flyer Model S?

[Dameon]

Mine is finally on the way... took a while to get a code.

My intended order of mods: 1) Variable speed accelerator switch, 2) rubber or rubber-coated tires, 3) Battery voltage upgrade (likely adapt Dewalt 20v MAX batteries, including the receptacle so I can swap like a hand tool battery).

Other than that, just enjoy it! I have no kids nor do I intend to. This is for me!

 

[David.85D]

I haven’t found a suitable variable speed switch to work with the standard battery - the battery is looking for some signal from the micro controller in the switch we haven’t figure out yet.

It won’t matter if you switch to some other batteries.

 

[Dameon]

I haven’t found a suitable variable speed switch to work with the standard battery - the battery is looking for some signal from the micro controller in the switch we haven’t figure out yet.

Do we know if the signal is a voltage sense or an encoded data stream? Surely it wouldn't be something overly complicated. Reminds me of when I was using a Prius accelerator for my home brew electric car conversion. It had a whole slew of wires for a device that shouldn't need many. Most of them were safety over rides... stuck open, stuck closed, 90% pushed or 100% pushed. Once I get mine, I'll test for output on the output side.

It won’t matter if you switch to some other batteries.

I figured that would be the "easy" part. The fabrication to make the car accept a non-modified Dewalt battery would be the tougher part. I intend to use a broken charger. It has the receptacle and contacts already in place and wired. Just pull all the charger stuff off and find a way to mount it cleanly. Possibly make space for (2) 20v batteries as the high amp hour Dewalt is only 6.0ah without getting into their potentially weird flex batteries.

 

[David.85D]

Post 42 links to the data sheet for the switch/controller. It’s digital. I was hoping someone would reach out to the manufacturer in China and get more detailed instructions

 

[Dameon]

Post 42 links to the data sheet for the switch/controller. It’s digital. I was hoping someone would reach out to the manufacturer in China and get more detailed instructions

Went back and checked... the link to the foreign site is gone. I'll have dig more for whatever schematics I can find.

Based on your pictures, moving the DP wire to the WK contact may give a result. Otherwise feeding B+ with a variable voltage from another (easier to diagram) switch, and closing the original switch all the time, might work.

 

[Krash]

...The fabrication to make the car accept a non-modified Dewalt battery would be the tougher part. I intend to use a broken charger. It has the receptacle and contacts already in place and wired...

Another option is use the 18v tool to 20v battery adapter .

 

[David.85D]

Here's the information from the Internet Archive. Looking for the actual datasheet now.

VS80B series Variable Speed switch with Microcontroller for t-Welcome to Shandong weida machinery co.,ltd.

 

[David.85D]

FWIW, the description says it can be configured as variable speed and can operate on up to 24V, so there is room for us to play with it, if we can figure out how to change the configuration.

 

[David.85D]

data sheet, extracted from the 2015 catalog, and a circuit diagram that appears in US Patent 7,705,260

From the layout of the prototyping board shown int he catalog, I think that simple push button switches somehow made on connections 1-4 set the mode. I have yet to find the specifics though.

working link to the manufacturer's site - VS80B - 上海拜骋电器有限公司

 

[foobar510]

hey folks I just bought one of these ride on cars, there isn't anything about it on modifiedpowerwheels.com but I want to soup it up for my kid. He has a 24 volt Lil' Lightning McQueen with a ESC and thumb throttle (mounted on the steering wheel). So we know how to push the envelope with these things.

So I am going to replace the 14.4 V battery with a 36V Li-ion battery pack (42V at full charge) from a hoverboard, I have a couple of them, they are light and super powerful, and also made out of 18650s (which is what I presume is in the fancy Tesla pack)

I've ordered a 36V, 500 watt speed controller, and a compatible accelerator pedal (basically a potentiometer) for under 30 bucks. My guess is the single black wire is some kind of battery authentication system to make sure the battery is authentic, but since I'm replacing the speed controller and battery, I won't need to crack it.
To increase the voltage by this much, it appears that there are some PTC's (auto resetting fuses) in series with the motors. Those will have to be replaced with a higher current capable overcurrent protection. I will also be adding a short circuit brake. When the motors are shorted, the rolling resistance gets very high (this also heats up and burns out the motors quicker, but motors in a souped up power wheels are essentially sacrificial parts anyways). I have a push button on the old one but it pretty much locks the wheels, need to figure out a more gradual braking system. The added weight of this car might also burn the motors out much faster than I am anticipating.

Finally don't try to hook up the higher voltage source without completely disconnecting the foot pedal and everything down from it (accessories). I popped a capacitor and probably something like the horn is permanently broken. No big loss.

Anyways should get the pedal and other stuff in the mail this weekend and will try to post some videos when it starts coming together. Hope others out there are souping up their radio flyer cars, these things are super cool!

 

[buttershrimp]

Anyone know any tricks to improve turning radius?

 

[foobar510]

Anyone know any tricks to improve turning radius?

There are little metal pegs welded to the top side of the steering rack that limit the turning angle, I am planning on filing those down or removing them entirely (there is about another inch or so of clearance until the front wheel binds on the inside of the fender). Nice thing is if you screw it up you can always just drill and tap a hole and put some bolts in to do the same job. If you do it let us know how it goes.

 

[buttershrimp]

There are little metal pegs welded to the top side of the steering rack that limit the turning angle, I am planning on filing those down or removing them entirely (there is about another inch or so of clearance until the front wheel binds on the inside of the fender). Nice thing is if you screw it up you can always just drill and tap a hole and put some bolts in to do the same job. If you do it let us know how it goes.

Genius, are you aware of anyone trying that? Also curious how you would access that? Sorry I just have a hard time picturing... do you think you’ll cut them with hacksaw? Turning radius is definitely in need of improvement

 

[foobar510]

Happy friday all, I made a bit of progress today that I'd like to report. I was able to cut off the nubs that limit the steering angle, I found the easiest way to do that was remove the steering rack entirely and used a dremel metal cutting wheel.

I have not driven it yet but it seems like you can only fully turn the wheel if you pull up on the wheel a little bit, so I am thinking maybe add a little spacer collar between the wheel and the dashboard to keep it lifted, if I can't figure out where it's binding.

It seemed to work but of course we haven't driven the thing yet. Second I hooked up the 36V battery, speed controller, and pedal. I used connectors I got from electricscooterparts.com. The battery and motor connectors are CNX-50s, and the speed controllers tend to use those and CNX-52 3 wire connectors. They are not too hard to assemble with a soldering iron and needle nose pliers if you don't have the crimper.

Next time I have a few hours free the next project will be to figure out the wiring on the forward/reverse and 1/2 low/high switches. I suspect that the low-high switch rearranges the motors in series for low and parallel for high. The forward/reverse switch is a little weird because it seems to have 4 wires coming out, my theory is that it only powers one motor in reverse so it's slower in reverse, but since I haven't actually seen the car driven I can't confirm. Can anybody let me know if only 1 wheel is powered in reverse?

Finally here is a video of the ESC working:

You can see from the sparks why I say that the motors are basically sacrifical.. I don't expect it to last a long time because the brushes will burn up.

 

[David.85D]

I just tested our car. Reverse powers both rear motors, not just one. Remember the original go-pedal is a drill switch with a microcontroller built in. The forward/reverse and high/low could be switching logic to that microcontroller (I don't know, just don't ignore the possibility).

And, ... good luck!

 

[foobar510]

Hey folks, quick Sunday night update on my progress. I have the ESC hooked up with low/high gear and forward/reverse. High/low is achieved by placing the motors in series for low gear (thus splitting the voltage between the two) or parallel (so both motors get the full voltage) with a clever arrangement of a double pole double throw switch. I am pretty sure the extra wires on the forward/reverse switch are to put the motors are in series (low gear) in reverse. Since I am relocating the high/low switch on the dash I'm not going to bother with figuring out how to wire them up that way.

I cut a hole in the side of the battery compartment in the trunk and put the hoverboard battery in there, connected with a XT60 to CNX-50 dongle I made. I also mounted the accelerator pedal by cutting out the flange that the old accelerator pedal mounted to and making a little aluminum plate. It's ugly but functional. I will probably 3D print a bracket at some point to close up the floor.

Showed the car to my kid for the first time today. He was pretty excited because he has outgrown his lil' lightning mcqueen but disappointed that we couldn't drive it today, he can only fit his feet in if he takes his shoes off now. Here's a video of him doing some donuts.

All that's left before it is driveable is mounting the low/high switch and a brake button on the dash, and figuring out where to secure the speed controller so all of the wires reach. Probably 1 more weekend session and it'll be ready to drive, I'll take some nice pics and diagrams then.

 

[BlackxP90D]

I've already stripped the entire factory harness, the only part I really want to use is the factory battery, which needs a serial command from the gas pedal switch to activate. Hopefully just holding it in the on position after changing the battery will keep everything on until the battery is low.

I'm waiting on a few other parts for the project.

Navio2 Autopilot
Reach RTK module
Sabertooth 2x32 motor driver
HS-7954SH high torque servo

The goal is for the car to fully autonomously drive around a pre-programmed route, with centimeter accurate GPS. Later on I want to add sonar and computer vision for obstacle avoidance.

Where you able to finish this project.

 

[buttershrimp]

Happy friday all, I made a bit of progress today that I'd like to report. I was able to cut off the nubs that limit the steering angle, I found the easiest way to do that was remove the steering rack entirely and used a dremel metal cutting wheel.
View attachment 386799
I have not driven it yet but it seems like you can only fully turn the wheel if you pull up on the wheel a little bit, so I am thinking maybe add a little spacer collar between the wheel and the dashboard to keep it lifted, if I can't figure out where it's binding.

It seemed to work but of course we haven't driven the thing yet. Second I hooked up the 36V battery, speed controller, and pedal. I used connectors I got from electricscooterparts.com. The battery and motor connectors are CNX-50s, and the speed controllers tend to use those and CNX-52 3 wire connectors. They are not too hard to assemble with a soldering iron and needle nose pliers if you don't have the crimper.

Next time I have a few hours free the next project will be to figure out the wiring on the forward/reverse and 1/2 low/high switches. I suspect that the low-high switch rearranges the motors in series for low and parallel for high. The forward/reverse switch is a little weird because it seems to have 4 wires coming out, my theory is that it only powers one motor in reverse so it's slower in reverse, but since I haven't actually seen the car driven I can't confirm. Can anybody let me know if only 1 wheel is powered in reverse?

Finally here is a video of the ESC working:

You can see from the sparks why I say that the motors are basically sacrifical.. I don't expect it to last a long time because the brushes will burn up.

I got the steering radius improved but I can see what you mean by the binding.... I need a spacer collar to try to prevent it... I am thinking of cutting into the trunk a small gash where the steering rack can go and add a little more turn. What do you think?

 

[mb300sd]

Where you able to finish this project.

Partially done, it drives with a remote. I constantly have like 20 projects going on and tend to lose interest when I have to wait too long for parts to ship. Will cycle back around to it eventually...

 

[foobar510]

Hey folks, I finished the 36V controller Tesla upgrade and drew this wiring diagram of the project.



The forward/reverse switch is actually 2 DPDT switches but I only needed to use 1. I also didn’t use the black tipped green/white wires that run from the front to the back. I was able to relocate the 1/2 switch into the plastic panel underneath the forward/reverse switch. Highly recommended. Kid understands to put it in 1 on the grass and around people and can put it in 2 to let it rip when he has space.

Kid loves the car and it gets a LOT of attention out and about. Even more than the Lightning McQueen. I am thinking about putting something sticky on the front tires to get them to grip a little better. It is so fast that understeer is a real problem. The steering rack mod to improve turning radius definitely seems to work though. He can make turns just about as tight as his previous lightning mcqueen.

https://photos.app.goo.gl/skj9g4TNdeGr4Fpx7

Biggest issue is that the car is so heavy the motors get HOT under braking because they dissapate so much heat, I am a little concerned that it will start a fire under the seat. I may look into heat pipes or something to move the heat. Any questions, please let me know! I will take a few pictures of the installation tonight.