[kaptain]

What does my battery voltage have to do with the inverters charging them? As long as they are over 10 volts the inverters should turn on and begin to charge them. But since you are asking, they are all over 12 volts.

Most inverters are inverters only, without a charging function. Some inverters, like what we have on Newell coach, have a dual function. Besides its inverter function (converting battery energy to 110/220V), it has a charging function too. 

However, such a dual-function inverter/charger usually works only if the battery voltage is at a specific voltage range. If the connected battery voltage is too low (no output) or too high (may go into a float mode, trickle a small current to maintain), it won't charge.