X2. I used to charge batteries a long time ago without removing the caps, unless it was a fully discharged battery. Not anymore. Once had a partially discharged one in a car, that still had enough juice to turn the engine over. Put it on low charge (2 amps) just to top it off. About an hour later, I was approx 30 feet away from the charging battery. Heard a loud pop, and plastic pieces were coming down, along with battery acid. Turns out the entire top blew off the battery, leaving only the posts and cables. Scared the you-know-what out of me. I no longer charge a battery in ANY condition with the caps on.
2003 Ford F-350 V-10 Crew Cab 4WD Long Bed
2004 Jayco Designer Medallion 29 RLTS 5th wheel
Bill, Gayle, and Mindi (dachshund)
Retired at last !
Nothing is foolproof to a sufficiently talented fool.