Wednesday, July 10, 2013


I've been fooling with 12 volt power of late, and seeing how complicated or simple it might be to depend on it. For this, I chose a single task; the powering of my 12 volt cooler. I used a separate 110 amp hour Kirkland (Costco) Deep Cycle battery. The initial take-home message is that I need much more solar collection ability than I have. Combined, my two 40 watt Coleman solar Panels are simply inadequate. I'm not quite getting 5 amps of charge from them, and that's only in ideal conditions. Thankfully, the cooler is quite efficient. The unit draws a maximum of 46 watts, or about 4 amps. Also, it's only cycled on for less than half the time so I'd estimate about 2 amp hours consumption. Assuming one does not want to run their battery much below half-way, we're looking at the single battery easily powering the cooler for a 24 hour period, but not much more. Of course while driving, the battery can charge back up, but if you want to stay put for a few days, you'll need a solution.
 Assuming nice sunshine, my setup can "maybe" put 50 amps back into the battery on a nice long summer day, if I move the panels to better face the sun as the day goes along. So, in reality I can barely keep up.
Knowing this, I think I will conclude that 200 watts of solar panel is a working "minimum".
 With that in mind, I'll probably try and sell my 2 40-watt panels and go with some larger ones. thankfully they are coming down in price. I could add another battery, but that would only be a partial fix. i.e. it would last another day or so, but then I'd still have to recharge everything. Depending on the amount of time you camp without an electric outlet of course, this whole discussion could be a little academic. Nevertheless, it's good to have options. Perhaps I 'll go back to propane refrigeration, but that's another story...