WillChair 2 Build Page 1

What do you do after you build something better, faster, and more durable (WillChair Build)?  You start over and build something else that's even better, faster, and more durable!  Fast forward a few years, a new house, job, shop, tools, and it's suddenly time for a remux.  The first build is getting long-in-the-tooth.  She's been abused like a rented mule for three years and needs some maintenance.  

A few specs on W2:

Width - 27 inches at widest point

Length - 43.5 inches from stem to stern

Seat Pan Height - 15 inches

Weight - 264 pounds fully dressed

Range - 30+ real miles; not uber inflated ISO test fantasy miles

Ground Clearance - 6.5 inches

Speed - 12 to 15mph depending on gearing

Suspension - 4 inches of travel

Power - 2,880 watt hours

Zero off-the-shelf powerchair parts except the seat cushion.  Every piece was manually cut from 6061 billet aluminum or A36 steel.  Even the plastic parts were built on a 3d printer.  The motors are brushless that were custom built to my specs.  The controller is a two channel robots unit running custom software.  The rear wheels are aircraft quality spun aluminum wrapped in 6 inch wide 4 ply commercial mower tires.  Actuators are IP rated industrial grade.  All fasteners are 304 or 316 stainless.  All electronics components are industrial or commercial grade.

Details.  It's all about the details.

Note the RC receivers.  Yes, it is radio controlled.  Why?  Ummm, why not?!?  If you ever have a chair with RC you'll never know how you got by without it.  

Just above the actuator on the right is the charge connector.  But lithium is complicated?  Nope.  It's simplified to one polarized connection.  You couldn't do it wrong if you tried.

This is actually the first chair I built.  No need in beating this one to death (yet).  One of the many benefits of RC and having enough power to be usable for something besides a glorified Barcalounger.

Custom built belt drive setup.  Gearing changes are quick and simple.  Go from trail cruiser to tractor puller in minutes.

Several goodies hidden inside.  Those are industrial tractor spindle bearings. 

The powerplant:  56 individual 3.6 volt LiFePo4 cells manipulated to produce 48 volts nominal with 60ah of capacity.  Complicated?  Maybe a bit but not too bad if you understand it.  Engineered correctly at this stage on the frontend makes it as simple as charging a cellphone and extremely durable on the backend for the user.  This pack only needs to be charged weekly and will last at least ten years.  There are 2,880 watt hours of energy here vs 1,080 or so on a typical powerchair.

Complete CAD packages, shop drawings, BOM, and wiring diagrams are available.

That was the highlights.  Follow along on the next few pages to see how she came together.

WillChair 2 Build Page 2