For my Hub motor build I’d like to upgrade to a slightly bigger battery to extend my range. Right now I use a selfmade 10S3P battery made from 25R cells (that is 270Wh). Source for cells and nickel strips was nkon.nl. The pack is reinforced with solid copper wire to guarantee no issues with high currents. I also added balancing cables to the cells so that they can be checked individually from time to time. The layout is made to fit my selfmade deck with two channels - so it consists of basically two 5S3P packs with each having 4mm heatshrinked female bullet connectors and a small male-male connector. The pack was never charged above 41V and has only seen maybe 4-5 full charge cycles.
Price: 170€ Location: Germany
Before heatshrinking the entire packs
With added balancing wires