Battery care for summer camp

 hi james,

 i can share some thoughts on how i might go about what you are shooting for. i lived for several years when i was a kid at the base of beautiful mount katahdin. can still remember being amazed to look up in july and see all that snow. can also remember making a few bucks in the winter shoveling off the roofs of local mobile homes in a nearby park.

 when choosing the makeup your pv array (assuming we are going to leave it in place)(rooftop?) we might want to consider a nice small framed module in the smaller wattage range over some of the larger 200 watt ones for loading reasons.

 for the winter i would decomission the array and pull ~100 watts of pv out and mount it on a south facing wall making up a small winter array to maintain my bank. not sure what your planning on for a battery bank size. but even the limited output of this small vertical array should keep our battery bank in float for the winter.

 agm's are great if you can swing it. but the workhorse of most stand alones is still the floodies and a quality battery with plenty of water room toped off in the fall should do fine, i should think.

 i would stick with a good quality charge controller with temp correction here and tend to stay away from a shunt type controllers with this application.

 should be able to knock up, scrounge, or buy some kind of battery box. a charged and "tickled" battery will handle the cold fairly well. we just won't have our rated capacity until it warms back up in march.

 just my opinions here..

good luck, dave

Since trickle chargers on an unattended battery would not be good for the long term health of the battery, I wonder if it would be wise to leave a small load on in the winter to 'work' the batteries.  Maybe a light or two? 

Are there any charge controllers that have a programmable energy 'dump' to deplete the batteries every so often when unattended?

Thanks for the suggestions so far.

Jim