Al, you’re right. I should have said chargethe battery only if you think it’s good. Tom seemed to think it might be okay. A sulfur smell is seldom good.
The only way a single hot battery can be expected and be considered normal is if the batteries in a bank are wired in parallel and the connections, both positive and negative, to the charger/inverter are off the same battery. This is the worst possible wiring scheme. If this battery bank is being chared at a high current rate the first battery will be warmer than the others.
Given the way this bank is wired, there shouldn’t be a single warm or hot battery.