Need advice on motor selection for my kids "toy"

MrGentry

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I just bought my kids a used Grave Digger power wheel with the metal frame and suspension. We bought it as a project to possibly turn into a gas powered kart, but for now I think we are going to stick with electric.
We plan to change the wheels to real wheels and tires (probably from a golf kart), which means ditching the motors that power the rear wheels. So a new motor is in order, and that's where I need some help.
One kid is 7 and weighs close to 80lbs and one is 5 and weighs close to 50. They like to ride together occasionally. The digger probably weighs 40-50lbs (est. from lifting it into a vehicle) currently.
I'm thinking of getting a 24v 500w motor kit, but not sure if that's going to be enough power (is it ever). I'd like to stay at 24v for the sake of weight, but if we need to go bigger we can. What advice do you have?
 

I74

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That 24v - 500w was my first thought when I read your title.

I lined up a Guy on another site with one of those set ups, & 2 - 24v Li packs wired in parallel ect. ect. ,, for a micro Mini bike.
He said it does pretty darn good for what it is, - '' think it's geared around 8.5 - 1'',, & the 24 v ''brushed'' stuff is fairly cheap.

Won't be anything fast,, but I would think a set up like that would probably get your kids around ok.
 
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MrGentry

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That 24v - 500w was my first thought when I read your title.

I lined up a Guy on another site with one of those set ups, & 2 - 24v Li packs wired in parallel ect. ect. ,, for a micro Mini bike.
He said it does pretty darn good for what it is, - '' think it's geared around 8.5 - 1'',, & the 24 v ''brushed'' stuff is fairly cheap.

Won't be anything fast,, but I would think a set up like that would probably get your kids around ok.
I'd like to get a 1000 watt, but haven't found one on 24 volt, likely because of the amp draw. The 24 volt stuff is fairly cheap, and we could always upgrade in the future to 36 or 48 I suppose.
 

I74

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36v 1000w would cruise ''you'' around some with proper gearing. ;)
I built my wife a 36v - 1000w BLDC set up Mini bike , that's powered by 2 - 10s - 4p Li packs wired in parallel.

Gearing on that is 6.5 - 1, & pulls my 210 lbs. just fine on the flats.

Also played around with the MY 1020 36v 1000w brushed set up once , & reworked the motor some,, & also messed around with the timing on it a bit ect.. That was a really ''strong'' / pretty impressive ''cheap motor & controller'' set up.
Those motors have 4 ''very stout'' brushes, that are positioned 90* apart from each other, & is pretty much bullet proof.

More I think of it,,, a 36v 1000w might be the way to go, right off the bat,, because your kids are not going to get any smaller ect.

That brushed set up after I tweaked it,, actually had more kick than the 36v BLDC set up.
 
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MrGentry

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36v 1000w would cruise ''you'' around some with proper gearing. ;)
I built my wife a 36v - 1000w BLDC set up Mini bike , that's powered by 2 - 10s - 4p Li packs wired in parallel.

Gearing on that is 6.5 - 1, & pulls my 210 lbs. just fine on the flats.

Also played around with the MY 1020 36v 1000w brushed set up once , & reworked the motor some,, & also messed around with the timing on it a bit ect.. That was a really ''strong'' / pretty impressive ''cheap motor & controller'' set up.
Those motors have 4 ''very stout'' brushes, that are positioned 90* apart from each other, & is pretty much bullet proof.

More I think of it,,, a 36v 1000w might be the way to go, right off the bat,, because your kids are not going to get any smaller ect.

That brushed set up after I tweaked it,, actually had more kick than the 36v BLDC set up.
I'll check prices on the kits. The 24v stuff is pretty cheap, and the power wheels is already 24v, so we could reuse the battery pack for the time being, but no, the kids aren't going to get smaller...unfortunately.
 

EpsilonZero

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We plan to change the wheels to real wheels and tires (probably from a golf kart), which means ditching the motors that power the rear wheels. So a new motor is in order, and that's where I need some help.

I went the route of rigging up lawnmower wheels to work with the original style gearboxes. The original 550 motors were garbage and I upgraded first to a Traxxas motor set and then a Holmes Hobbies TorqueMaster Expert 550 21t matched set with 12deg advance. The new motors are faster, quieter, and cooler running with a double bearing design. This is running on just a 12v controller from EastCoast PowerUp and a Dakota Lithium 23Ah battery. My controller is discontinued, but they still make power wheels 24v versions.

20200813_175647.jpg20200704_193023.jpg20200704_192544.jpg20200704_192537.jpg20200704_184808.jpg
 

I74

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I went the route of rigging up lawnmower wheels to work with the original style gearboxes. The original 550 motors were garbage and I upgraded first to a Traxxas motor set and then a Holmes Hobbies TorqueMaster Expert 550 21t matched set with 12deg advance. The new motors are faster, quieter, and cooler running with a double bearing design. This is running on just a 12v controller from EastCoast PowerUp and a Dakota Lithium 23Ah battery. My controller is discontinued, but they still make power wheels 24v versions.

View attachment 125102View attachment 125103View attachment 125104View attachment 125105View attachment 125106
Looks like the kids are pulling you along,, pretty cool ! :)
 

MrGentry

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I went the route of rigging up lawnmower wheels to work with the original style gearboxes. The original 550 motors were garbage and I upgraded first to a Traxxas motor set and then a Holmes Hobbies TorqueMaster Expert 550 21t matched set with 12deg advance. The new motors are faster, quieter, and cooler running with a double bearing design. This is running on just a 12v controller from EastCoast PowerUp and a Dakota Lithium 23Ah battery. My controller is discontinued, but they still make power wheels 24v versions.

View attachment 125102View attachment 125103View attachment 125104View attachment 125105View attachment 125106
Did you make that hub or buy it somewhere?
 

EpsilonZero

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Did you make that hub or buy it somewhere?

I made the hub from some PVC board, a plastic transmission gear from Amazon, and some bolts, nuts, and washers. I also used some copper pipe as a bushing so the wheels would fit on the existing spindles. I also had to drill holes in the wheels to attach my makeshift hub. The fronts were of course easier with basically just having to cut a copper bushing for each.

If you're going to do something like this and use plastic gearboxes, I highly suggest cleaning off the grease that comes pre-"applied" (often just a dollop here or there) and replace it with something better. I am using DOW Molykote EM-30L synthetic grease and haven't seen warping or gear stripping since. I even returned a couple of damaged gearboxes to service (previously heat-warped and partially fused gear/housing) and kept using them for months without failure.
 
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MrGentry

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I made the hub from some PVC board, a plastic transmission gear from Amazon, and some bolts, nuts, and washers. I also used some copper pipe as a bushing so the wheels would fit on the existing spindles. I also had to drill holes in the wheels to attach my makeshift hub. The fronts were of course easier with basically just having to cut a copper bushing for each.

If you're going to do something like this and use plastic gearboxes, I highly suggest cleaning off the grease that comes pre-"applied" (often just a dollop here or there) and replace it with something better. I am using DOW Molykote EM-30L synthetic grease and haven't seen warping or gear stripping since. I even returned a couple of damaged gearboxes to service (previously heat-warped and partially fused gear/housing) and kept using them for months without failure.
The hubs looked good. My plan is to remove the stock stuff and run a live axle. Eventually I may convert it to a gas go kart but for now I think electric is the best option.
 

EpsilonZero

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The hubs looked good. My plan is to remove the stock stuff and run a live axle. Eventually I may convert it to a gas go kart but for now I think electric is the best option.
Does that power wheel have a full length metal frame?
 
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