I had my 2 motorhomes stored all winter in a non-heated polebarn with no electric for charging. We did have a little milder winter this year than last. It only got to -7F a couple of times and most time was between 0 & 10F. Last week both started up with no boost or any problems. Radio settings remained as last fall. A fully charged battery should hold with no problem.
1999 Damon Challenger 310 Ford