I have spent the last couple of years thinking about how I could increase the range of my Magic Mobility X4 wheelchair. The obvious solution was to change the batteries from lead acid to lithium. Doing so in a way that is safe, is reasonably cost-effective, and has sufficient power for dramatically increased range has been a bit of a challenge.
About 6 months ago, I started to get serious about this project. I spent several months procuring all the bits and pieces. My friend, Greg, helped me put everything together (as he has done on so many other projects). After several weeks of testing the cells that would come together to form the battery, and then testing the assembled battery, we were finally ready to install the mess.
Greg came over yesterday and we spent about 4 high-quality hours doing the install. After we were done, I was able to test the chair in the garage to prove that it worked! It did.
Today, I was able to wrap up a few loose ends and took it out for the first real test drive. I planned to just go 100 yards, because the forecast was for snow and looked like the snow could start any time. Once I got in the chair and went 100 yards, I knew it was not nearly enough. I wound up going 5.2 miles and had a blast.
Based on the preliminary computations of energy used on that test ride, it looks like the batteries will allow me to exceed my goal of a range of 12 miles. That is a lot better than the 4 to 5 miles that I could get with lead acid batteries.
I will need to do a lot more testing to ensure that the system is really stable, but the initial indications are quite positive.
Obviously, I am pretty tired today. I will be resting a lot in the upcoming week. I do have another ski outing scheduled for Tuesday, though
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Here are a couple of pictures. The first is of my friend Greg surveying his work. The second gives a better view of the 8 lithium cells (LiFePO4) that make up the battery pack along with all the necessary wiring.
Steve