I had an incident this weekend where my electronic brake pin was accidentally pulled, which enabled the trailer brake overnight. We woke up to the LP monitor beeping due to low battery power, and there were other weird electrical anomalies happening.
We decided we'd have to leave when I realized my 2 x 6V GC2 batteries were registering 4V only. Ouch!
It's then that I noticed the pin was pulled for the trailer brake, which I assume is the sole reason for the low voltage.
When I spoke to the dealer, they recommended that I charge the dead batteries on a dedicated charger at 12A, (not the built in 3 stage charger in the trailer). I used a charger that I have, and set it to the Pb function which cuts off at 2.4V per cell. I followed their recommendations and kept the two 6V batteries connected in Series and set the charger for a 12V battery. When I checked on it, the amps had started climbing down, and the charger was reading 14.4V. This should be the cutoff voltage for Bulk charging, and then I was going to lower the amps to 2A for Absorption. The thing was, I heard the batteries "bubbling" which made me think they were boiling inside.
Is this normal? I'm new to to this stuff and only know a bit from what I've read.
I've since taken it off the main charger and have hooked it up to my battery tender, in hopes it will finish off the job, as it should be done.