Alarm

We have a 2014 keystone Laredo. We have not used it for 7 months, we took it off t yesterday, everything was fine until I was gated I into a he electrical at the rv park and within a minute the most horrible life of d alarm went off . It was nice but it he carbon monoxide or smoke alarm.? The alarm was piercing. My husband checked the propane tanks and realized one day f to be tanks was slightly left on, th worm can ntinu d, he is as going to disconnect the he battery, took a th from very off, took the battery charge lead off and the alarm stopped. No propane smell, the alarm did not go off again. The button in for he travel now says d the battery is fully charged. Anyone have any idea what the alarm went off? Thanks for any Help