I am on holiday without my external charger and my 18650s in my GX350 have run out of battery. I just purchased 2 18650s and am curious about the negative effects running two dead and two full(ish) new 18650s. Also wondering about the orientation of married batteries after learning of the "2 married pairs" recommendation. Does anyone know of these details?
You could get away with using the new set in just dual battery mode as they will be equal in charge and strength.
It is never advisable to run a multi-battery mod with batteries that are unbalanced, the lower weaker batteries will put undue stress on themselves or the stronger fresh set, which can lead to a venting issue as the stronger batteries will try to charge the weaker ones on top of providing power you are pulling from them.
Married = bought together, charged together, used together, never cheating on the others until death do they part.