Thank you for all the feedback everyone has provided. It is great to know that folks have followed along on my adventure. I sure appreciate all the encouragement I receive here.
I had two primary reasons for embarking on this project. The first was purely practical. I wanted to see if there was a way to increase the range of the X4 wheelchair. It has been a wonderful chair and I have really enjoyed having it. But, a range of 4 miles has been very limiting.
The second was to do something that would keep my mind busy learning new things. Batteries and electronics are not new to me, but I had never done a project like this. I have learned so much doing it and it has been great fun.
Now that the project is mostly wrapped up, I can say that it has been tremendously worthwhile. I have learned much and have a deeper understanding of how energy is stored by various battery chemistries and how that energy is released from the battery when there is a demand.
The X4 wheelchair has a maximum speed of 4.2 miles per hour (up from 3.6 with lead acid batteries). If I am going at full speed for 6 hours, I would only go about 25 miles. I don't think there will ever be a day when I can ride at full speed for 6 hours. It has been remarkable having a wheelchair whose range is greater than what I am able to ride in a day. That means there are no effective limits imposed by the wheelchair. It is now the only wheelchair I have that does not cause me to turn around early because the batteries are getting low.
I have informed my friends that I am looking for hiking partners who can match the range of the X4. So far, I have not had many takers
The X4 wheelchair was a derelict when we obtained it 3 years ago. It took months to get it back to where it could be used. I was never satisfied with the wiring it came with and had always hoped to do something about that. This project gave us the opportunity to address some (but not all) of the wiring issues. I am much happier with it now.
There is still work to be done. I would like to rework more of the wiring and, especially, clean up the wiring for the seat elevate function.
I look forward to many more projects like this one. I am now investigating using LiFePO4 batteries in another wheelchair. I just have not decided which one yet!