Depleted battery question
I unplugged my trailer from shore power for a few days and forgot to plug it back in. Went out there and obviously batteries were dead as interior lights were super dim. Ask my husband to plug it back in to shore to recharge and see this is were it gets scary. After a couple of hours I noticed a rotten sulfur smell, not equating it to the trailer or batteries went on with my day. A few hours later 10pm, fire department rolled up knocked on the door asking if we smelled anything weird. Husband said he had and they continued through the hood looking for the smell. 15 mins later gas company came knocking, husband gets up and he and the gas company traced it to the trailer and the batteries. Thank god I didn't burn the hood down. Question is it because the batteries dried out or what would cause that. I've had depleted batteries before without them frying like this.