When you charge batteries, you keep like-charged batteries together; you never just replace one … even though it’s tempting and it keeps the flashlight going at half the cost. Why? … the lower-charged battery SUCKS THE ENERGY out of the good battery. It just can’t keep up always providing the energy in the partnership and carrying the load, so it soon loses its charge… faster than if it had been teamed with a battery of similar juice. You might be tempted to fault the new battery that lost its charge faster than you thought it should, (or lost its patience) when the cause is really the damn old battery that isn't trying to do its share.
I’ve drawn my line… my personal boundary … my space. I won’t let you back across. You are a dead battery to me.