Hi folks, first of all I want to say thank you for a great forum here. I have followed this forum for quite a while and love it. I have not posted because I did not have anything really to offer that had not been covered. Until maybe now. For my purposes I have been studying building my own batteries out of lithium ion cells (primarily 18650's). There is a lot of great information and instructions on lots of forums/youtube etc. regarding this. But I noticed that here, mostly everyone buys commercially available batteries and pay the markup for someone else building them. If the process of a proper build are followed closely, it seems that you can build a good battery with more mAh that is safe and save a lot of money. You can do it with new ...or even used cells. My question is, if that is so, why are the folks in the robot community not pursuing this?