I would agree, but I did fold up about 4^2” of foil into little tabs, so there was a decent amount of surface area. The easiest would be to just dedicate the single cell charger to the pump and solder wires to the contacts with some nice tabs. But since it might be another 5 years until we camp like this again, I probably won’t.
I’ll add my 30Q charged to 3.8V also dropped, but only to 3.3V also. It was definitely delivering more current based on the sound, but at the levels being delivered (+5A) my meter with really long leads is not going to do the measurement justice.
Main reason to go parallel is to reduce current draw per cell and voltage sag. I can’t use all the capacity in this pack as it pulls the voltage down to 3V a cell before 1/4 of the capacity is used. I’m about to rebuild my ebike battery, so I’ll probably swap out these cells for 8 of the Sanyo GAs from the bike battery. Even though they have only ~60% of the capacity of new, that’s still more than these cells and I’ll be able to use more of it.