Yes, it is over built, yes the wheels are big and no the welding is not first rate. But it is mine, I built it, it works. So there!
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Building a Battery Cart

It is over built because I am 60-something and getting smarter

Text & photos by Tom Hintz

Posted – 5-3-2013

One of the “I didn’t think of that” things that came up after I started flying electric powered radio control planes was the labor involved in taking a deep cycle marine type 12V battery to the field for recharging battery packs for the planes. Since a decent airplane battery pack can cost $35 to $50 (and more) buying an $80.00 deep cycle automotive-type battery made perfect sense. What was not as smart was my not recognizing the challenge of carrying a 47-lb battery from the garage to the car, the car to the table at the flying field and then back to the car and then back into the garage.

Big Wheels

I looked through my steel supply and noted that I had plenty of 1” angle and 2”-wide flat stock so I went to the store and picked up four 6” wheels (ball bearing naturally), four ½”-diameter bolts (for axles), eight washers and four nylon insert lock nuts. I know the 6”-tall wheels sound too big but remember the 47-lb battery that they would carry and the grass I had to pull this cart (and battery) through to get to the table at the flying field. Bigger wheels just handle irregular surfaces and running over grass better.

I used 1/2" bolts (hardened) for axles and nylon insert nuts to keep them on. I am not fooling around wi th this project. It's a build once, use forever deal.
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Ground Clearance

Another good thought on my part was to elevate the bed of the Battery Cart enough to prevent it dragging excessively in the grass it was running over. To set the ground clearance I piled two pieces of scrap wood (1-1/2” total) and set the bare frame on that. Then I could locate the axles, stuck through the wheels in the right spots on the frame tabs to attain that 1-1/2” ground clearance. This procedure also helped me get all four axles placed so that I actually had all four wheels on the ground at the same time – mostly.

Assembly

I measured the bottom of my battery case and cut four pieces of 1” angle, mitered on both ends to make the basic frame of the Battery Cart. I know this is overkill on the materials but it is what I had and I don’t want any surprises like the battery dragging on the ground later. I welded up the angles to make the rectangular base and test fit the battery (in its carry case) in the frame just to be sure. It fit perfectly.
Then I cut four 2”-long pieces of 2”-wide by 3/16”-thick steel bar to serve as mounting points for the axles. I welded one of those at each end of the long sides of the frame. Then I put a bolt into a wheel, held that assembly against the frame (still on the blocks of wood) and tacked the bolts/axles to the tabs, one in each corner. With all four axles in place I finished welding them onto the tabs.

I found a piece of 1”-wise by about ¼”-thick steel with a hole already drilled near the end so I cut off three inches of that. I put the piece in my big vise, hole end up and about 1” of the other end clamped in the jaws so I could get out my hand sledge and beat an angle into it. That piece was then welded to the underside of the (now) front of the Battery Cart to serve as the hitching point for a dog leash with which it would be pulled.

Here you can see the grass-missing 1-1/2" of ground clearance and the simple "hitch" where the dog leash will hook up.
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I wire brushed the whole assembly and taped up the axles to keep them paint free. Then I hung the Battery Cart on a wire and shot a good coat of primer and then followed that with three coats of red paint. The following day I removed the masking tape, installed the wheels and put the battery in the cart and shoved it across the floor.

It rolled nice so I was done. Still need to buy the leash.

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