# Electric wheelbarrow



## qwerty256 (Jun 19, 2012)

I'm building a 4 wheel electric wheelbarrow/micro dumper, somewhat similar to a Muck Truck. I'm not sure yet if I will drive all four wheels or only the rear wheels.

Steering of the Muck Truck is done by pulling the handles to one side and/or lifting one of the handles to shift the weight. Having used one, I can say this works fine.

I was told that this scheme will not work for my electric wheelbarrow because it's not going to have a differential.

Do you think this will work?


----------



## Woodsmith (Jun 5, 2008)

If you don't have a diff then you will really struggle to turn it if it is carrying a weight that you would need a powered barrow for.

Easier would be to have two motors, one motor driving each side and then steer by powering one motor at a time.

Taking the parts off a powered wheelchair, preferably one that is no longer needed, would give a lot of the parts you would need and a joystick controller.


----------



## qwerty256 (Jun 19, 2012)

Woodsmith said:


> If you don't have a diff then you will really struggle to turn it if it is carrying a weight that you would need a powered barrow for.
> 
> Easier would be to have two motors, one motor driving each side and then steer by powering one motor at a time.


Thank you for your reply. 

Using two motors and separate controllers was my first plan, but changed to one motor with just on/off control, to simplify the wheelbarrow.

Looks like I'm back to two motors..


----------



## Woodsmith (Jun 5, 2008)

You can still have 'on/off' control for two motors. The voltage and current draw probably won't be huge so contactors or starter solenoids would probably do it.

You can get winch solenoids that allow simple forward/reverse in one unit at 12v or 24v.


----------



## dragonsgate (May 19, 2012)

Woody posted this on another thread but something like it might work for the wheelbarrow plus you could disengage it so you could move around it by hand if need be. 









This type fits at a suitable place ahead or behind the trailer's road wheel and is activated to press hard on the tyre and then drive it in either direction.

I am sure it could be fitted to the wheels of a car and the activation can be automated from the cockpit and then remote driven. Many of these things have a remote handset for moving caravans and trailers about. ****
The video didn’t load. Go to electric motors/ Ideal motor for power bursts to move car in this diy forum to see the demo.


----------



## qwerty256 (Jun 19, 2012)

The frame for the wheelbarrow is mostly finished now. I used square 25mm steel tubes welded together. I was lucky to get two small (400mm) tractor wheels. I will buy two more wheels of the same size.

I will probably use two 350W 24V geared scooter motors from ebay (MY1016Z3 T11). It's hard to find reliable specs for these motors.. After some searching, it looks like it's ~2.5amp no load, 18-19amp continuously and ~100amp if stalled. I have seen the rpm for this motor/gear as anything from 303 to 425rpm. Does anyone have a link to more detailed/reliable specs? A torque/rpm/current curve would be very useful.

I built an H-bridge using mosfets on a breadboard. It works fine to switch direction of a smaller DC motor, but need to build it on a pcb with larger mosfets to use it for this. I will probably use the H-bridge, but considering simply using an DPDT toggle switch for each motor.. The largest I have found is rated for 20A, more than the rated current, but much less than the stall current. Will this work? How do switches fail if the current is too high?


----------



## dougingraham (Jul 26, 2011)

qwerty256 said:


> The largest I have found is rated for 20A, more than the rated current, but much less than the stall current. Will this work? How do switches fail if the current is too high?


Couple of possibilities.

The contacts weld shut.

The internal mechanism turns to plasma and the circuit opens.

The switch mechanism opens but current continues to flow by jumping the gap.

The contact faces become pitted and resistance goes up.

Make sure the rating is for DC amps. Generally they are rated for the ability to switch the current. They can often carry a lot more current than they can switch.


----------



## Ziggythewiz (May 16, 2010)

They go up to 50A at my local store. You should be able to find better than 20A switches online.


----------



## qwerty256 (Jun 19, 2012)

Ziggythewiz said:


> They go up to 50A at my local store. You should be able to find better than 20A switches online.


I didn't find any >20amp DPDT rated for >=24VDC. Didn't look to many places, since I will probably go with the mosfet H-bridge.


----------

