Needed a spot welder to connect the cells, well need is a strong word...wanted for various reasons. I really wanted an alternative to soldiering the cells. The cells don't like a lot of heat, it can cause damage and reduce capacity. This (Sunkko 709AD) was one of the best consumer mini spot-welders available at the time. Supposedly the 220V model is much better, but I have had success with mine so far.
Trusty cell holders!
These cells were ordered from Terry on eBay. They didn't quite test up to snuff when I checked them. They were supposed to all be ~2600mAh, but they turned out to be closer to 2250-2300mAh. When I let him know, he adjusted the price and gave me a decent discount to make it right. I really appreciated Terry's efforts and would buy from him in the future. Here is his eBay store: https://www.ebay.com/str/power2spare
These cells from Terry came out of medical packs and were stuck with ultra sticky foam. He tries his best
I ordered these (above) cells from Battery Hookup (batteryhookup.com) and they were all tested and labelled before shipping out. I was very pleased with their quality (exactly as advertised) and that they tested as reported. I only had to re-wrap a few of these since they put kapton tape on the exposed wrapper portion. I also bought the 36v packs from Battery Hookup via their eBay store: https://www.ebay.com/str/tomhasgooddeals or their new website: https://batteryhookup.com/
Big Config 1
Initially, I was going to make big batteries that would be 14s and 28p (series and parallel).
Big Config 2
After making the second one, I decided that I had a better idea for using a better BMS (Battery Management System) solution.