I’ve had 4 lipos which are now dead, but part of the problem was that they discharged unevenly. I had this idea of connecting the cells of each battery in parallel e.g cell 1 of battery 1 connects to cell 1 of battery 2. Although this theoretically would work to keep all cells at the same voltage, if cell 1 of battery 1 discharged quicker than cell 1 of battery 2 could this cause cell1 battery 1 to be charged to quickly and die. Hope someone can shed some light on this!
There are risks with that plan, but not too severe. I would personally charge them each individually to as close to identical voltages as possible and then hook them all up together. Remember, when working with lithium batteries make sure they are at storage charge. The lower the voltage, the less reactive the lithium is with oxygen if you fail catastrophically. The damage will be limited significantly with storage charge cells
If you mean charging/storing them in parallel and then discharging them in series, that can work. You cannot, however, have your packs connected in series and parallel at the same time.
Or, you know, you could just use a BMS - a system specifically designed to prevent that exact problem, without all the changing-around.
Using well-matched cells/packs and not running them too hard also helps tremendously.