I have news! Some good, some... less good.
So the thing is built. It has brakes. One of which is for stopping when you want, and works great. The other is a safety for stopping the thing if you let go. It works less great. I need to introduce another spring or something to give it more oomph. It seems to be good on power. I loaded it up with some bricks and gravel I had on hand, I'm estimating 150-200 lbs worth, and it had no trouble at all hauling it up my driveway. Seemed like it could probably keep up a jogging pace with that kind of load.
That's about the end of the good news. The bad news is I made some design mistakes, and the setup has some inherent flaws.
Design mistake number 1: Setting the wheels so they are much closer to centered under the load than on a traditional wheel barrow. Felt like a good idea at the time, considering the kind of load I wanted to haul, and the distance I wanted to haul it. Seemed like it would add a little bit of balancing challenge, but put much less of the weight on the operator.
Design mistake number 2: As you may be able to tell in the picture, it is noticeably taller than your average wheel barrow. This is because I wanted it to clear the batteries, figuring out exactly how long those legs should be to clear the batteries was complicated, and I thought it better to err on the side of slightly too tall. Seems like I landed on much too tall. I have something like 6 inches I could stand to lose before it would risk hitting the batteries, and I think I am going to be cutting legs and rewelding them to get rid of most of that excess.
Design flaws 1 and 2 combine to create a very awkward situation when encountering obstacles. The thing is very keen to keep moving when the wheels stop, and with the height, and the wheels being further back, most of the tip prevention comes down to the driver. Not an easy thing with the kind of weight were dealing with.
This is where the inherent flaw comes in to make things even more fun. Transaxle sounded like a lovely idea, but for my specific circumstances, I am now interested in ways of disabling it. If I hit a root, pothole, bump, whatever, with one tire but not the other (very likely with this trail) the motor has no problem at all with letting that wheel stop, and just sending the power to the other wheel instead. This causes the thing to turn toward the stopped wheel. The weight in the barrow obviously wants to keep moving straight. Since I designed the thing to pivot from side to side, to deal with awkward terrain, I now have a few hundred lbs trying to keep going straight while the wheels go sideways, and the structure in between provides no resistance to it doing just that.
So these three problems mean that when I went to put it away in my garage and hit a 2x4 with the left wheel, it turned sideways, pitched forward, and tried to roll over to the right pretty much all at the same time. I'm perfectly happy dealing with the design issues, its really just labor, nothing much to figure out. The one I would like advice on is the transaxle. Is it plausible to open it up and lock some parts together to get it to act like a solid axle?
Oh, there was also a weird electrical thing it was doing. I turned it on the first time and it functioned just like I would expect. I went inside, came back out and the motor wouldn't kick on. I messed with it for a bit, checking voltage on the batteries, finding no problem, eventually I unplugged it and plugged it back in and it worked again. After screwing around with it for a while it seems fairly consistent. After turning it on, then letting it sit for a minute, it wont work until power is disconnected and reconnected. Hitting the on/off switch doesn't do it, it only starts working if you disconnect the power entirely.
