i installed an electric gate opener at the s&b a while back, the kind that runs on a car battery but has built-in charging controller. i bought a new deep cycle marine battery for it but cycled my old one out of the camper to the gate and kept the new one for the camper. made sense to me at the time.
now it's a year or so down the road after the install and my kid comes in from work about 1am last lite. i'm just drifting off to that warm, fuzzy place, and WHAM! BOOM! sounded just like when the power transformer out front got hit with lightning last year. kid calls, 'dad! come quick! the gate just blew up!'.
got there to find pieces of the battery and the weather plastic case it lived in strewn across 25 feet of driveway and the road beyond. battery was ripped open on both sides showing plates like a monster movie shows teeth, top caps blown off, case badly buckled, most of the weather case totally gone. the kid was petrified, thought his car had blown up.
kid said it went off just as he pressed the clicker to open the gate. today, after i cleaned up the mess, i put in a new battery, checking the charge volts and amps. 16v open ckt, 14 v loaded with the battery. amps <1a. gate worked ok afterwards.
point is, maybe this could have happened while that battery was in the camper! hate to think of it like that, but let's be real... it might uv.
anyone here have any such experiences? any ideas about the science of why good batteries turn bad and go boom in the night?