I found a guy that can get his hands on used/rejected 18V Makita Lithium Ion battery packs. These packs use Konion 18650VT cells, 10 per pack. From his experience of working with a lot of these used packs, you get at least 8 good cells out of every pack. I plan on building a 14s14p Lithium Ion battery for my scooter. The beauty of these is you don't need to balance charge them, you can monitor them but balance charging is not necessary. I should be able to build this pack for under $500 total and have enough cells to fix my three cordless drills