Power Wheels
- Thread starter RClippa
- Start date
This morning is not great. The blisters are pretty bad, and my wife is not happy with my stupidity. She should know better by now. Even with a left hand that is not full strength I am excited to get back tonight. I am about to head to the dump to empty my trailer so I can get wood to the shop to start the seat bases. While out and about I need to pick up some 3/4" shaft collars to fix the position of the rear wheels on the axle shaft. All goes well I should be able to test drive tonight to see if I need two motors or one! I also need to order new tires. These are pretty old and don't hold air. I was going to just tube them, but after looking it really isn't that much more expensive to just put new rubber on.
Toolbox? haha. That is so he can carry my beer this halloween!
97TJGUZZY
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even better!!!
Last night was a big old flop. I decided to try out the power on the thing before I went to much further. I figured that if I have to rebuild the powertrain side I need to know now. Well I need to rebuild the powertrain side. I am just not sure to what extent. The single motor was torquing up so much that it could twist the motor mount and misalign the chain. This didn't help me at all. Between this and some questionable wiring the thing wouldn't even climb over a 2x4. Very disappointing. I need to do some more testing to figure out where the problem lies. I guess I will rewire it and see if that does it. Then I can try to remove the speed controller and see if that is a current limit. Finally, maybe rebuild the motor mount to be more rigid?
If that all fails I am not sure what path I will take. I can setup the second motor, but between the gears, chain, and larger speed controller I will likely be in that upgrade for around $100. I could throw the kitchen sink at it and upgrade to a 1800W brushless 48V motor system. Certain to push this cart all over the place. That will set me back around $130 for the motor and controller and another $120 for two more batteries. It is pretty much guaranteed to work though. If I setup both the motors I have now I will only be around 700W of motor power. Is an additional $150 worth more than double the power? I know, I know. Yes it is! But that is another $250 into a project that is wildly over budget. I am nearing the point on this project that I can't hide the cost in my normal spending.
If that all fails I am not sure what path I will take. I can setup the second motor, but between the gears, chain, and larger speed controller I will likely be in that upgrade for around $100. I could throw the kitchen sink at it and upgrade to a 1800W brushless 48V motor system. Certain to push this cart all over the place. That will set me back around $130 for the motor and controller and another $120 for two more batteries. It is pretty much guaranteed to work though. If I setup both the motors I have now I will only be around 700W of motor power. Is an additional $150 worth more than double the power? I know, I know. Yes it is! But that is another $250 into a project that is wildly over budget. I am nearing the point on this project that I can't hide the cost in my normal spending.
I think I am going to give it a shot to patch what is there. I am going to try a more rigid motor mount to maintain chain alignment. Then up some wire gauge issues and see if that helps. Then I will just bypass the speed controller and see if that controller is just not putting enough duty cycle through to the motor. Then I have to make the call on trying a different gearing and losing some top speed, dual motor, or mega motor with battery upgrade. I am struggling with that one knowing that this is a 2-3 year toy. Then they will be old enough for RZR racing.
Last night I spent my time working to solve my powertrain problems. I cut out the old motor mounts and built a new mount. Rather than use a pivot style mount I converted to a slotted style mount. This thing is more rigid, but it still deflects under the full torque of the motor. I will need to stiffen the mount even further. This helped but didn't solve my torque problems. I didn't expect it to, but tried anyway.
I am now looking at adjusting the gearing and sacrificing top speed for some hill climbing torque. It looks like I can get a 15 tooth sprocket for the rear axle that will give me a 50% increase in wheel torque and keeps it at a 6mph top speed. This is where I am thinking I will land, but I will go ahead and put both motors on. This will give me a massive jump in torque without having to go 48v. I want the 48v but I would have to run a jackshaft to reduce the speed so it would be suitable for a 5 year old. Without it the thing would go 15-20mph. I will save that for the next project.
I am now looking at adjusting the gearing and sacrificing top speed for some hill climbing torque. It looks like I can get a 15 tooth sprocket for the rear axle that will give me a 50% increase in wheel torque and keeps it at a 6mph top speed. This is where I am thinking I will land, but I will go ahead and put both motors on. This will give me a massive jump in torque without having to go 48v. I want the 48v but I would have to run a jackshaft to reduce the speed so it would be suitable for a 5 year old. Without it the thing would go 15-20mph. I will save that for the next project.
The chair was actually a direct drive. My current ratio is not far off, but is a slight overdrive. The new ratio on Monday will be a 40% under drive. This plus the parts for the second motor will increase the torque from what it is today to 3x larger. That should remove all of my concerns around the system.
I didn't head over there last night. Yesterday was the anniversary of our engagement so the wife and I celebrated with some great Italian food and a good bottle of wine. Tonight I will work on the second motor mount and finishing up the metal fab. I am ready to get to paint. I have also started the seats, but with everything shut down it is hard to get the fabric I need.
I didn't head over there last night. Yesterday was the anniversary of our engagement so the wife and I celebrated with some great Italian food and a good bottle of wine. Tonight I will work on the second motor mount and finishing up the metal fab. I am ready to get to paint. I have also started the seats, but with everything shut down it is hard to get the fabric I need.
Got the second motor mount wrapped up. I just need the sprockets and speed controller to show up and it should be in monster truck mode. I also mounted the last of the exterior metal. Just a dash and one closeout to finish up and then it is finishing work time!
Check out that front wheel travel!
Check out that front wheel travel!
needed to use one motor for front tires and one for the rear axle
The thought crossed my mind, but the staggered tires would make it complicated and the steering would get significantly stiffer. While a 4 year old is seemingly strong, I am not sure they could handle that. I am already designing a differential for the rear to make life easier on him.
The new sprokets showed up this morning. Sadly, I can't find anything that matches the motors so my night was spent matching the bore and broaching new key ways into them. I did manage a short drive at the end of the night. With my weight in it, there was a lot to be desired but I am not a small person so the kids should be happy for now.
Old final drive versus new. Both motors installed and ready to go. I need to figure out a good way to manage the electro magnetic brake system in the motors.
Old final drive versus new. Both motors installed and ready to go. I need to figure out a good way to manage the electro magnetic brake system in the motors.
Not sure exactly what you mean by Electromagnet Brake but im imagining it has some sort of secondary coil that as you entergize it releases?
Might be kinda cool to build up a little arduino with a mosfet to to ramp up/down that brake voltage.
Might be kinda cool to build up a little arduino with a mosfet to to ramp up/down that brake voltage.
I tore one apart and it is a coil mounted to the back of the motor. When energized it pulls a spring loaded steel plate off of some brake material and frees the motor up to spin. It is more powerful than the motor itself. I tried to full current a motor against it and there was no slip.
Now the question is, do I ditch my current speed controller and just build one. I found a 40amp regenerative H-Bridge that can handle both motors. It needs a controller to drive it though. I could do a quick Arduino to read the accel pedal and maybe a brake switch. Then I could fade the system inbetween motoring, regen braking, and friction braking. If it falls in line with our buses, I could extend the range by up to 25%. It is a lot of work though since in the end I will be putting a 2000w brushless motor system on this thing.
97TJGUZZY
SUPPORTER
when you say there was a lot to be desired, how does it compare to a typical power wheels?