I completely disconnect my fully charged battery bank when parked here over the winter months... It starts out reading around 12.6-7VDC and usually only drops down to around 12.4-5VDC over NOV DEC and JAN...
During the winter months I can read my batteries with only my Battery monitor meter connected and I usually check on it ever two or three weeks...
Sometimes when it gets down to 12.5VDC I will hookup my trickle charge for a day or two... This next winter season I will have my 10WATT small solar panel hooked up all the time giving the batteries a slow continuous trickle charge.
If you let them set you have to pull one of the battery terminals otherwise the parasitic drains will run them down in just a week.. Its best to install a disconnect switch as removing and replacing the battery terminal may or may not keep you with a good solid connection depending how tightly you install the terminal each time...
Hopefully your batteries are not damaged. Once they go below 12.0VDC it is like driving a nail in their coffin... Do a slow long charge on them using a smart mode charging mode charger. Do it two or threes time in a roll...
Got to take care of the batteries as they are your lifeline for trailers.
AT least once a month when sitting here between trips I do a walk around and read the sitting battery voltage. I like to always read at least 12.5VDC or more. Then I switch in the batteries to the trailer and hook up to my garage receptacle which turns on the converter/charger unit and then I look at the battery terminals DC VOLTAGE again and I want to see it jump up to the 13.6VDC or higher depending what smart mode the charger jumps up to. If I don't see the DC VOLTAGE jump up then that tells me my Battery charging system is not working...
Roy Ken
