Dusty R wrote:
Why not put a battery disconnect on the battery?
Is there any ill effect to a modern automotive engine with the battery being disconnected for 3 months?
Won't hurt the engine but will not help either.
Radio presets are not the only thing that will be lost.
Modern engine/drive train systems require constant 12V power to retain all learned settings.
In a nutshell the engine ECU will "learn" and retain all operating parameters as you drive. Those parameters are then used to make precise adjustments to your engine spark and fuel system along with learning and adjusting your transmission control for upshift and downshift.
Disconnect the battery for more than a couple of minutes and all that learned info is lost.
While this doesn't hurt anything it doesn't help in the fact that the computer will need to go through multiple complete "cycles" (cold to fully hot back to cold) which will affect emissions, fuel economy and sometimes drivability until the computer has optimized adjustments.
Read your vehicles owners manual for how to complete the ECU learning cycles.
For yrs I have jumpered in an additional battery power source to the vehicle when replacing starting battery in my vehicles in order to not lose the ECU settings.
Depending on what you have available, you can add a 50W solar panel with a solar controller to keep your starting battery charged if no shore power is available.
If you have shore power available you could just buy a 120V multistage charger for the starting battery. Not expensive and you can leave it wired up so all you have to do is plug in the MH and the rest is taken care of without needing to do anything else.
I have one like this..
on my whole house backup gen battery. It is a 5A fully automatic three stage charger and cost about $30
FOUND HERE5A isn't going to boil the battery to death and with multistage charging it will drop to maintenance charging voltage of about 13.2V.