Made it out again, just after the sun set. Ran power to her and got her charging. /quote]
If you can leave power out to the boat try putting a clamp light with a 100W incandescent bulb (ha those are getting scarce) in the engine compartment. that keeps thigs warm enough to keep the oil a little thinner and easier to start.
I also use some inexpensive float chargers on my batteries while I am away, once they are fully charged.
Fully charged batteries store well when cold I am told.