Instead of the Sanyo 20700B's I'm trying to build my next pack out of Sanyo 20700A cells. Obviously they have less capacity, just 3100mAh... but they are also rated at 30A continuous discharge per a cell, and from what I have heard, that is a realistic number. My goal is to build basically the smallest/lightest 20s pack I could that would be able to utilize the 3000w power of my new Cyclone. I'm going to try to pull this off with a 20s2p pack, for my short distance rides that will be the majority of my use of the bike.
Now for the cool part about this. I'm getting these Sanyo 20700A cells from 18v 6.3ah Bosch battery packs. Each oack is costing roughly $55 shipped, and contains 10 cells in a 5s2p pack. On top of that, the cells are already inside a nice holder that's supposed to be some kind of cooling plastic (considering these are Bosch, I wouldn't doubt this being true... though I am not too familiar with plastic). ALSO, the cells are already connected by a copper plate that is laser welded to the cells, with copper tabs at the beginning and end of each pack, making it pretty damn easy to connect these packs into a 20s pack (could really do it pretty easily with a simple soldering iron... WITHOUT the issue of causing damage due to over heating the battery by directly soldering to the cells). Given this 20s pack will only be a 6.3ah pack... but that should be plenty for 90% of my rides, and I plan to make a second or possibly 3rd to run in parallel for longer rides.
If you ask me, for the price, and the fact that these cells are pretty much all set up, good to go... could easily be done with minimal cost in tools (I assume anyone making their own pack already owns a halfway decent soldering iron)... and the 40 cells + holder + copper plate laser welded (better than any home welder is gonna do) only cost about $220 so far.
Like I said, trying to go small and lightweight, but still make 3000w of power. If I was going for capacity.. and could find a good source for them, I'd go with the Sanyo 20700B most likely... tho I currently don't know any good place to get them at a good price. I suspect they'll be showing up inside some power tool's high capacity power pack soon enough... or something comparable. And for me, not being able to find battery holders the right size would be pretty trivial... I can easily 3D model and print them to the exact size and layout I want (given I already have multiple 3d printers... but even if I didn't... could get one for under $300 that would be more than adequate to do the job).