On these types of charges- just make it a habit to pop in once a month and unplug the charger, turn on headlights for a couple minutes to drain the “surface charge” then test voltage. 14.4 is the max charging voltage you ever want. Battery with surface charge off should no more than 12.6 volts. If it is over 12.6- set a timer to go check it next month and see if it’s ready to plug back in.
We say 12volts, but each cell actually has 2.1volts not 2volts.
6 cells X 2.1 volts= 12.6 volts.
Over charging a battery is WORSE than it sitting under charged.
A battery at 11.6 volts will start most engines, a battery at 11.1 volts will start some engines in modern temperature. A battery at 13.6 volts is out gassing its acid into hydrogen and swelling up the battery from heat. If the lead plates don’t short inside and ruin the battery, then the case will swell up and crack. Liquid acid (normal) batteries then leak acid everywhere. AGM (optima/odyssey gel type) simply crack but continue working without leaks until the lead finally shorts inside.
Remember when charging ALL automotive type batteries discharge hydrogen gas. You can turn off the charger but the gas remains.
Safety Sally moment. Unplug and ventilate (turn on a fan) the air around the long term charging battery before starting.
Below is pics of a group 31 battery common in semi trucks, heavy equipment, etc.
85 lbs & 13”x6.75”x9.5” roughly. This battery lives on a high dollar very accurate charger for emergency use generator. The batteries were less than 2 years old, impeccably maintained equipment. Two batteries in series operated at 24V for the equipment. The on board charger was verified amperage and voltage in optimal range and no smell of hydrogen sulfide present, as witnessed by the two professionals present. One person had a multimeter attached to the battery inline with the one that exploded, not attached directly to the battery that failed. He was monitoring voltage drop upon start while the other person starts the generator. The battery suffered an INTERIOR FAILURE where the connection opens, and trapped hydrogen sulfide gas ignited. There is the possibility the gasses picked up a spark from the surrounding area but no loose wires or source of that spark was able to be determined from the thorough investigation that followed.
The person at the battery location was as safe position as possible by distance yet still able to monitor his meter. The ignition causes the battery to explode sending the top of the battery hitting the angled side of the engine then the person in glancing blow and still traveling 20’ beyond the person. Multiple shrapnel pieces of the battery case scattered with a piece the size of a silver dollar found 40-45’ away.
The acid spray went straight up, ricocheted of the angle of the engine traveling as far a 30’ that was detectable. The person was sprayed hut immediately treated suffering only small bruise and cut from glancing blow, protective clothing ruined along with meter. No long term injury to the person. I can’t say who these people are but some of the members here have met them or one of them- that part will not be discussed- read the room.
UGGHH! I tried but can’t get pics to load. I will get attempt to reset and load them later.