E-powered beach/sand cart

[njcart]

Hello all, first post on here but I have been reading up for awhile.

I am going to attempt to add an additional powered drive axle to a beach cart like this:

Another view showing handle that you pull on.

The cart is ment to haul standup jetskis (300lbs) over the sand. Pulling the cart over the sand is difficult and wears you out before you get to ride. I am not looking for the motor to do 100% of the work....but I am hoping it will add a good amount of "assist". Because I om only looking for a top speed of 3mph...I chose one of the unite GEARED 600watt 36v motors (MY1020Z3). I will use a rear axle off of an ATV and try to get the biggest sprocket I can find for the atv axle. The below drawing was made using sophisticated CAD software....MS Paint...lol. It does not show the fancy mounting brackets, ect I am working on, but it gets the point of what I am trying to accomplish across.

This is the 36v controller I am going to use and I also bought the matching throttle for it.
http://www.tncscooters.com/XK-022D-5.php
*I will be using (3) 18AH 12v AGM jetski batteries wired for 36v.

Questions:
1) Controller has a single wire "charge inhibitor connector"...can I just leave this unconnected?
2) Controller has "brake connector" with 2 wires. Can I just leave these unconnected, or do I need to connect them together to fool the controller?
3) Has anyone fitted a #520 chain sprocket to one of these geared motors? That would make life easier...but I think I will have to do my backup plan. Which is to just to find the largest #420 sprocket I can find (around 60-70 tooth) and weld/bolt it to the existing ATV sprocket on the axle. The motor has a gear Ratio: 60:9 (6.67) already built in, and if I can keep the 10tooth drive sprocket and have a 60-70tooth driven sprocket I think my max speed will be right where I need it (3-4mph)..WITH MOST IMPORTANTLY A GOOD AMOUNT OF TORQUE!

Any other feedback, comments, suggestions are GREATLY appreciated!
Thanks.

 

[Ykick]

Interesting? Will this be submerged for launching/landing?

Seems like there should be a simple yet elegant configuration somewhere in there?

'sorry not any help but I like the project...

 

[njcart]

Interesting? Will this be submerged for launching/landing?

Seems like there should be a simple yet elegant configuration somewhere in there?

'sorry not any help but I like the project...

Thanks. No the cart will definetly NOT be submerged...lol The motorized cart is just to get the jetski from the truck to the water's edge, and vice verse. The cart has a winch on the handle to crank the jetski back on to it. The skis are light enough for one person to drag the final few feet into the water without too much trouble.

 

[Rassy]

Cool project. I'm sure you considered many possibilities, but it seems to me it would work good to put the second axle at the front of the trailer on a pivot so you could steer it with a little tongue like a kid's wagon has.

Then you could add a seat and ride it to the waters edge. Your weight would give you traction on the drive wheels.

Good luck with the project.

 

[njcart]

Cool project. I'm sure you considered many possibilities, but it seems to me it would work good to put the second axle at the front of the trailer on a pivot so you could steer it with a little tongue like a kid's wagon has.

Then you could add a seat and ride it to the waters edge. Your weight would give you traction on the drive wheels.

Good luck with the project.

LOL, I did think about putting a seat on it...lol But inorder to keep it as simple, light, and as transportable as possible, it will still be manually steered by the person "pulling" it. Honestly there is really no steering required, its a strait shot from the truck to the water most places here. I am trying to make it as simple as possible, so that there is no more then 5-10mins of "setup" time when I arrive and unpack it from my truck. The reason I wanted to keep the axles as close together as possible is that the jetski itself will be sitting on the bunks, with majority of the ski's engine weight hanging over the drive axle. I think that will help ensure it has adaquate traction, but that is yet to be seen.

This might demonstrate what I mean about the jetski's weight placement over future new axle better then me describing it. Being that its all box aluminum its easy enough to drill a new hole in the tube and adjust how far the axles are spaced.

 

[njcart]

Update.
After much debate I decided to over gear. Making a custom #40 80tooth monster 13" sprocket for the ATV axle with a 10tooth #40 on the motor. That should let the motor run in its happy full RPM zone and produce a max 3.6mph with the 21" tires I'm running. Ordered all the supplies and I will be making the mounting plates for the motor this weekend.

Anyone have any answers to the controller wire questions? The controller is the only part I am not that comfortable with.
Questions:
1) Controller has a single wire "charge inhibitor connector"...can I just leave this unconnected?
2) Controller has "brake connector" with 2 wires. Can I just leave these unconnected, or do I need to connect them together to fool the controller?

THANKS!

 

[amberwolf]

If you don't need extra support of the second axle, then there is a simpler idea: bolt a "tophat" adapter to the inside of one of the wheels, and a sprocket to that. Drive that sprocket from the motor, and there you have your power assist. If you need evenly-driven wheels or better traction, you could put tophats/sprockets on both wheels, driven either by a single motor (with a long axle between two sprockets) or two separate ones.

I don't know about the "charge inhibit" wire, but hte brake wires you just leave unconnected.

 

[Ykick]

This isn't gonna need much of a duty cycle will it? If its only gonna run for seconds at a time I wonder about something like an ICE starter motor and a ring gear on the back of one of the trailer wheels? It's not as if you're gonna drive it for 30 minutes across town...

Are the ATV axles easy to come by?

 

[njcart]

If you don't need extra support of the second axle, then there is a simpler idea: bolt a "tophat" adapter to the inside of one of the wheels, and a sprocket to that. Drive that sprocket from the motor, and there you have your power assist. If you need evenly-driven wheels or better traction, you could put tophats/sprockets on both wheels, driven either by a single motor (with a long axle between two sprockets) or two separate ones.

I don't know about the "charge inhibit" wire, but hte brake wires you just leave unconnected.

I dont need the extra support of the 2nd axle, but I want to make this as modular as possible as I use the same cart for loading IN the water occasionally. So ideally the motor driven axle will just be a quick pin and it will slide out of the standard beach cart, leaving the beachcart intact in its stock form. I want to make the battery box just as easy to remove, and use quick connects for the throttle. Appreciate the ideas though.

 

[njcart]

This isn't gonna need much of a duty cycle will it? If its only gonna run for seconds at a time I wonder about something like an ICE starter motor and a ring gear on the back of one of the trailer wheels? It's not as if you're gonna drive it for 30 minutes across town...

Are the ATV axles easy to come by?

You are correct the duty cycle will only be 2-4, 400' roundtrip runs from parking lot to the waters edge. With breaks in between for loading and unloading the skis. The fullsize ATV axles can be had all day long on ebay for $100-120, and are probably overkill for this application. I am looking into using the chinese knock off child size 110cc ATV axles for future carts, as they are much lighter (and cheaper), but they are limiting on how big of tires you can run, and may not meet my width requirements for adiquate stability. The sand duty really needs 21" OD minimum tires.

 

[Pure]

It seems like to me mixing electrics and salt water would be a bad idea. I know DC motors will run submerged in plain H20 but am not sure salt water would be a good idea. I know you said that it would not be getting wet, but that would kind of defeat the full use of that trailer It is after all meant to be backed into the surf by hand until the ski lifts (floats) off, fully or mostly submerging the rear end and drive components. Even using it like you are describing still leaves your motor very vulnerable to contact with the salt water.

I really think a better (also probably easier) idea would be to weld a bicycle fork with powered front wheel on to a standard swing down trailer (I have no clue what these things are called, but it's the part of a trailer that swings down and locks into place when you are putting a trailer on or off of your car.) Then use some sort of wagon type of handle to pull and control the cart. Using a bike hub motor on the front will mean that the motor in the front has to go in less deep of water and the added clearance of the 26" rim will also help keep your motor out of the water. Besides all that, hub motors are very easy to seal.

 

[njcart]

It seems like to me mixing electrics and salt water would be a bad idea. I know DC motors will run submerged in plain H20 but am not sure salt water would be a good idea. I know you said that it would not be getting wet, but that would kind of defeat the full use of that trailer It is after all meant to be backed into the surf by hand until the ski lifts (floats) off, fully or mostly submerging the rear end and drive components. Even using it like you are describing still leaves your motor very vulnerable to contact with the salt water.

I really think a better (also probably easier) idea would be to weld a bicycle fork with powered front wheel on to a standard swing down trailer (I have no clue what these things are called, but it's the part of a trailer that swings down and locks into place when you are putting a trailer on or off of your car.) Then use some sort of wagon type of handle to pull and control the cart. Using a bike hub motor on the front will mean that the motor in the front has to go in less deep of water and the added clearance of the 26" rim will also help keep your motor out of the water. Besides all that, hub motors are very easy to seal.

Appreciate the feedback. You might be confusing the hand cart used for moving the ski, with the roadworthy trailer that is hitched onto the back of the truck and backed into the water. The only thing I am looking to add motor assist to is the handcart pictured above. This handcart will never be "dunked" "splashed" or otherwise come into contact with salt water, while the motor and modular atv axle setup is attached to it. If I am going to use the cart in the water it will look exactly like the first picture I posed up top, with NO electionics/atv axle, ect on it. I know this does defeat the purpose of the handcart some making it non submerable, but in practice it will work just fine for my needs. Believe me, with the jetski electronics I am very familiar with maintaining a DC ignition system that does come into constant contact with saltwater. Its not fun...lol Thats why I am designing the "assist axle" and the attached motor/electronics to be molular and quickly removable if I choose to use the cart IN the water. Moreso then salt water...I am worried about the motor getting sand in it from the vent holes in the back of the housing. Thats going to be a tough one to avoid.

 

[amberwolf]

I really think a better (also probably easier) idea would be to weld a bicycle fork with powered front wheel on to a standard swing down trailer (I have no clue what these things are called, but it's the part of a trailer that swings down and locks into place when you are putting a trailer on or off of your car.) Then use some sort of wagon type of handle to pull and control the cart. Using a bike hub motor on the front will mean that the motor in the front has to go in less deep of water and the added clearance of the 26" rim will also help keep your motor out of the water. Besides all that, hub motors are very easy to seal.

Actually, hub motors are kinda difficult to fully seal, from all of what I've seen reported.

But mroe than that, a bicycle wheel is not going to give the traction this cart will need--not in sand. It has to have large balloon tires on there to do that. This can be done, but no existing bicycle fork except maybe a Hanebrinks would fit such a wheel.

 

[njcart]

But mroe than that, a bicycle wheel is not going to give the traction this cart will need--not in sand. It has to have large balloon tires on there to do that. This can be done, but no existing bicycle fork except maybe a Hanebrinks would fit such a wheel.

This was my thinking as well, even with these big 21" ballon tires.... in really deep gnarly sand its though to move the cart over it. The tires are really key to this spreading the load out and floating it over the sand. The power assist SHOULD make the task easier. Hopefully...lol

 

[amberwolf]

If not, at least it'll make it easier to dig nice holes.

 

[njcart]

If not, at least it'll make it easier to dig nice holes.

If there was a thumbs up icon I would have posted it...lol

 

[ronnieb52]

Currie 24 Volt, 5-Pin Controller.

*Please note: The Over Charge Protector (Charge Inhibitor) does not need to be hooked up. It is a safety feature on newer model scooters so that the scooter won't run while it's charging. This controller works with older models without using the Over Charge Protector plug.