Back when I lived in california I had a friend who worked at Tesla who offered to sell me a Nissan Leaf battery pack they tore apart. I paid about 95$ per module and I never really did a whole lot with them. I happen to have eight of them in Philadelphia and more in my barn in illinois. If you are interested in some really really big batteries, please let me know. These batteries can give a lot of power, so could be used for portable welders and everything. And yes I do have enough to make a 48v pack for a cargo bike.