Quote:
Originally Posted by CharlesMoore
Sailboaters have for years used less than 800AH battery capacity and a few 200W solar panels to run for weeks at a time off the generator. They lack few creature comforts and with some judicious use of power go for two weeks or more without the genset.
The minute you throw in the air conditioner all thoughts of off the grid go asunder. This includes Lithium options that are priced within the realm of the common retiree. We are not really there right now.
There exist a few new nano technology battery options on the horizon that offer 10x the capacity and almost instant recharge capability if the gen-set allows. Alas, this technology may be 10 years away. So either do without the aircon or use the generator.
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This...
We did 3 years with 300 watts solar (poly, not mono due to shading from sailboat rig) and 420aH AGM - had refrigeration, no AC and never owned a generator, and not once did we need to start the engine to charge. This is all possible with a thoughtful install and judicious use of power. That being said, we ran a 3000w pure sine inverter connected directly into the shore power mains with a manual transfer switch and had full ability to charge phones, laptops, camera equipment, blender, hair dryer occasionally, water maker, water pumps, fans, lights, just as if we were plugged into shore power. The things that made this possible were a quality battery monitor (Victron), and high volume low draw 12V fans to stay cool. For refrigeration anything with a "swing compressor" is ideal. They are some of the most efficient ever made - ours would run on either 12v DC or 120v AC, though I only ever used DC (compressor is 12v DC native, so why waste efficiency converting precious energy to 120v only to then again waste efficiency changing it back?) and the draw was 2.5 amps DC under full load, the icecream would be solid!
My point is that off grid energy use is much less about energy production - that's the easy part, it's all about storage capacity and usage efficiency/monitoring.