The Actual Mountain Wheelchair Motors are Working!

…plus lots of other updates

It’s been a little quiet on the blog over the last week or thereabouts so I wanted to I’d like to share a number of things that have happened during that time…

Spokes

After dropping off the motors and wheel rims at Halfords in Llandudno, the guys were able to take all of the measurements, but weren’t able to locate the correct spokes from any of their suppliers. Just like me, they did some digging around and the only suppliers they could find were in China. I’ve since ordered the spokes from China, but of course they’re all celebrating the Chinese new year at the moment so it’s going to be a number of weeks before they arrive.

Battery Pack

The first 48v battery pack is ready. After bottom balancing all of the cells, I was impressed as they were charging as most of them remained within 0.001v of each other, and there was just one other cells which was 0.002v behind the others. Fully charged, this is a 56.5v battery:

Interestingly, John Williamson (Aka Burgerman) of www.wheelchairdriver.com has been reading through my posts, and based on his background working with charger manufacturers in an advisory capacity for 25 years, he’s suggested that bottom balancing is the wrong way to go about this. Thanks for taking the time to read my posts John, I think more research is required on my part.

Grinding away the Dropouts

With much trepidation, I spent a large part of yesterday grinding away part of the BMX forks to get the motor axles to fit. Looking at them though, I’m really worried that the dropouts on the forks (the part where the axle will sit), aren’t going to handle the torque produced by these motors. I’ve had to file so much away, that there’s far less metal on the forks now than there used to be. Originally, I imagine an engineer would have calculated how much metal needs to be there:

Snapped dropouts is a common problem with e-bikes:

To overcome this, you can buy and attach what’s called a universal torque arm. This arm takes the torque produced by the motor and transfers some of it higher up the forks where they are stronger:

My only problem with this is that I think they look untidy. I gave it some thought last night and have made some rough sketches of a purpose built “torque arm” that will bolt to the frame. If I can get those made up at a reasonable price that’s what I’ll do, if not then I guess I’ll have to go with these unsightly universal torque arms.

At least the motors look cool now that they’re sitting in place and Ada’s really pleased with the purple dust cups which she chose.

Motor Controllers

Six motor controllers arrived from China yesterday and at first glance I’m really happy with them. They’re far smaller than I expected them to be which means they’ll be easy to fit within the mountain wheelchair frame.

The main problem I have with these controllers though is that the Chinese user manuals have been badly translated into English. Trying to understand what the manual is trying to say is rather difficult.

Whilst I was waiting for the controllers to arrive, I was however able to produce a wiring diagram to provide power the 6 motors:

Once I had the wiring diagram and knew what I wanted to achieve, I then spent days searching through online components for the parts I needed. Trying to find a simple thing like a 48v switch (200a and waterproof) has been impossible in the UK so I’ve had to resort to getting parts shipped from China again.

Actual working Mountain Wheelchair Motors

Nonetheless, and this is quite a big moment, I’ve just managed to get the actual mountain wheelchair motors running for the first time!

You’ll have to excuse the temporary wiring, but, Woohoo! It’s working!

 

Mountain Wheelchair Motors have been left at Halfords

This was the scariest moment so far in the mountain wheelchair build…

Last night, I dropped off all of the motors and wheel rims at Halfords Autocentre in LLandudno.

This will be first task that I’ve had to get somebody else in to complete and I felt extremely nervous walking away, leaving all of the wheelchair parts in somebody else’s hands – What if they don’t do a good job of it? What if they drop one of the motors? What if something gets damaged? Do they realise how important they are?

To be honest, the two people I spoke to were very reassuring, and the girl at the counter added to the label “Guard with your life”.

They were kind enough to let me take a photo for the blog – “bye bye motors, it was nice knowing you”

And, they even said they’d take some photos as they carried out the work which was pretty cool.

If you’re reading this Will, then I’d just like to say a big thank you for offering to do it. In the end I thought it best to go to a store to do it because it meant that if they did get damaged then I’d be able to recover the costs.

All in all, I’m a little nervous, but at the same time extremely excited. The wheels were one of the first things I started thinking about when I began this journey. Once the motors are sitting in their rims, they will be the first part the mountain wheelchair which will be finished. No more research, no more designing, done, finito!

So long as everything goes well of course :S

*Update*

Received a call from Halfords the following day to say that they had done all of the measurements and found that they needed an odd size spoke which they couldn’t obtain from their suppliers. They did however email me a link to some on ebay, but they’d need to be shipped from China. The good news is that they’ve done all of the measurements and at least now I know what size spokes to get.

I’ve been into Halfords to collect the motors as the motor controllers will soon be arriving and I want to start playing with the electronics whilst I’m waiting for spokes to arrive.