The battery is complete and I have been riding the bike for a few days now. Here are some photos of the build and the bike:
test fitting the pack inside the battery box. I had to be very cautious since the case is conductive and I haven't fully insulated the pack yet.
How I terminated the positive end of the pack. I folded the nickle sheet over and then added more spot welds. You can see a couple spot welding mistakes where I missed the mark. Otherwise it went pretty smoothly.
Added some 3mm thick rubber padding
Soldering the positive cable. As suggested my many on ES, I finally purchased a fat tip soldering iron (80W) since my butane torch stopped working. What a difference it is having an adequate sized soldering iron! I used a lot of solder on those 8AWG cables but I am happy with the result. I made a goof when selecting the solder to use. I had accidentally used 40/60 rosin core instead of 60/40 rosin core. That explains why the soldering appeared more dull. I switched back to 60/40 as soon as I realized what happened.
Pretty happy with how the box turned out.
I am happy I chose XLR connectors for charging. The make a nice solid connection.
Current pulled after first real ride. As expected, the performance of this new 14S7P 40T pack is virtually the same as when I was running a 14S5P 30Q + 14S6P 25R. It has a bit less voltage sag which is exactly what I was after, although not much less. The real benefit is having one pack instead of two. Charging and riding is more enjoyable.
I'm quite proud of how everything turned out, especially for my first cylindrical cell pack. There are definitely some issues I need to address with the battery box but nothing that is stopping me from riding.
If kind of funny. I was used to riding the fat bike since last fall and up to now. This bike is a completely different ride (street vs offroad). When I twisted the throttle for the first time on the bike since last year, the acceleration is enough to make me laugh and be a bit frightened.