Electrical Power

I am an offshore sailor.  I am used to spending a week or two offshore.  I understand was is needed to be off grid, and that is my goal for this camper.  I don't want to have to plug in anywhere, and I want to have everything I need to live in this camper for two weeks at a time, or longer.  I also want it to be comfortable such that I could live in it for an extended period, 3-4 months without going crazy, and that means holing up in in for several days in extreme weather.

My plan in to make small improvements, of the sort most people would do to bring a new camper up to a functional standard.  I also want to reduce my energy consumption, while improving my battery storage and charging capability.

The first thing I did was to put a 250 A-H 8D battery into this camper.  It fit perfectly, but but it needs a special charger to charger it properly.  Gel Cells are sensitive to charging voltages, over charging, and need a slower charge rate.

One weakness of this camper is the converter/charger which put's .5 A per hour back into the battery. and does not stop.  If left on, it will over charge a battery and ruin it.  However, it is such a slow charger, that this would take a while. Still I would not leave it charging for more than a day or two.

Unfortunately, all of the drop in replacement converter/chargers are biased for flooded batteries.  AGM batteries would work fine and that is my goal--to replace my Gel Cell with two 8D AGM batteries, and update the wiring to the converter, while installing a better converter/charger.

However, if I use solar panels for charging and I have enough of them, I won't need to plug in a charger at all.  I ordered, four (4) 105 Watt solar panels, which will give me 420 watts of charging.  I can mount all of these near the front of the roof well clear of obstructions that might block sunlight. 

From my yachting experience, I know that I can count on about five hours of full output on the average every day.  Really this is just a multiplier to estimate charging capability for horizontally mounted panels.  That works out to 2100 Watt-Hours.  Using a 40 Watt MPPT controller I can expect about 166 A-H per day on clear days and should see at least 20 A-H on the darkest, most over cast days.

Some people will tilt solar panels to capture more of the sun's rays, especially in the winter.  Typically, winter sun angle decrease charging by 50%.  Tilting will increase that by 30%.  Tilting mechanisms can be awkward to use, and if you forget, you can easily rip the off hitting overhead obstructions.  If I need more power in the winter, I'll add two more panels and a higher capacity charge controller. 

In any event, a strong solar charging system will mitigate the need for a better converter/charger.