Four dangerous battery things I have experienced:
VW battery located under back seat next to metal frame good idea to remove ring from finger as enough space to connect positive to ground.
Battery exploded while being charged outdoors in the sun, luckily I was away at work when it exploded.
36 volt battery bank for electric bike, overcharged due to electronic charger failure to shut down, great amount of H2S produced, luckily it was outside. Fumes were strong enough to be able to smell exiting the RV.
Dropped wrench fell across posts of battery bank of golf cart batteries, fixed by covering all posts with split rubber hose. This was on boat but it reminds me that I have a similar situation in the RV, time to split some more rubber hose