[robertrael]

Sorry this is wordy, I thought too long on how to present all the details. MY TL;DR is at the bottom.

I ran my Golf Cart batteries (Energizer EGC2 T105) 6V each in series completely out of water (I think.) Each battery took a gallon of distilled water to fill. I'm sure this is covered somewhere here, but maybe someone can help me determine if I have ruined my batteries? The date code on one of the batteries says 1/11, so I may have lucked out (for the most part) and it might have been time to replace them soon anyhow.

I have a solar panel on the batteries constantly, but for about 1-2 weeks we got cloudy days and a lot of rain, something we're not used to here in San Diego.

I have charged the batteries to full capacity as reported by my Xantrex converter/inverter, yet with no inverter load the voltage reading seems to drop rather quick. No inverter load is confirmed by the reading on the output of the inverter as being zero.

I'll be honest, I never really paid attention to the voltage and voltage drop, but I know the inverter shuts down at somewhere around 11.? volts. When I first disconnect from shore power, I see 13.1 V from the batteries, and maybe 5-10 minutes later I see 12.6 and lower. At this point, the only things on the battery were the carbon monoxide detector, and the bat wing antenna. I can't think of anything else that was using the battery at that point.

TL;DR
Full charge on batteries, rapid voltage drop as reported by inverter with no inverter load, and minimal battery load. One of 2 batteries has a 1/11 sticker on it. I made the mistake of running the batteries dry.