Definitely understood. The water pump analogy was definitely not perfect, just my most recent experience. I do realize that building a huge battery like this is a project, but it's also not rocket science.
You bring up some good points about the challenges of building the pack and they certainly are challenges.
A. Fit: Pouch cells are are certainly energy dense so fitment is more of a challenge with cyllindrical cells. But we've also come a long way since Zero announced they had the densest cells in the market. To match voltage we'd need 28S, to match capacity we'd need 30P. That's 840 cells.
Zero battery box is about 10" wide. You can fit 3 cells side by side and still have 1.5" extra for wires, tape, foam, etc. Tight but doable. So basically you're looking at 3 side by side packs of batteries.
The pack is about 16" long. If we use 17 cells in this direction We would still have 2" for other materials.
It's also 16" high. So let's say we have 2 of the 3 packs at 15 cells high, with the 3rd one containing the remaining cells with the last, impartial row at 13 cells high. This leaves about 3.5" above the pack, in the enclose for the BMS.
This is not to say this is the most optimal way to fit the batteries, I haven't even accounted for staggering them, but they definitely fit. If I play around with more configurations I could potentially fit a lot more cells, and if necessary I could always extend out into the area where the storage/powertank/chargetank sits.
B. This is a legitimate issue that I definitely need to do more research on. It's clear that batteries are best with temp management. But Zero basically doesn't do temp management. We've seen their cells overheat from charging and especially from long freeway rides and extended trips from people who charge and ride back to back multiple times a day.
The question is really how much are the tesla cells going to heat up under my personal normal use vs the farasis cells, how much loads effect the heat etc. The tesla cells are rated to reach up to 70c under load, while the farasis are rated to 55c. Farasis rated for continuous discharge of 87A, and the tesla cells are rated for only 15A continuous. But when you consider we're talking 8 tesla cells per 1 farasis cell, an 87A load would only be 11A~ per tesla cell. So the bike would be working with a significantly bigger margin.
I really don't know the answer to this question and more research is warranted. Perhaps I would need to do something similar to what
Alta did for their cylindrical cells.
C. This is honestly trivial compared to the rest of the build, and even in the worst case scenario it's a non-issue to me since I do not ride in the rain.
D. BMS's aren't black magic. There are a huge number of them available and programming them isn't complex. I'm not concerned about this part of the process at all.
E. This is really the main thing I've been trying to ask about, which is how much of the bike is integrated with the battery. There are a ton or resources for building batteries, but there isn't a lot of info on how the zero controller and mobo integrate with the BMS. I've heard people on this forum do some programming changes themselves on the controller but I'm unclear on the line between what is user programmable and what requires dealer tools.