bigcitypopo wrote:
We (I) have geared her whole rig around 12V living... I ran an anmeter and she drew 68AH over a 2 day period... Just fridge, some LED lights and 12v TV.. I think I want to set her up with 3 of those 140w panels....
68 amps over a 2 day period is 34 amp hours a day. Two 140W panels will be more than enough. Was this measured in the summer or the winter, when the nights are longer? You'd probably have her do fine with two 100 watt or 120 watt panels, with her usage level.
I go through 35-45 amps a day, and I am using a 150W panel... 8.4 amp peak charge rate, and an adjustable voltage charge controller, set at 15.0V daily. I find it easier to keep batteries in tip top shape with that voltage setting when camping. I disconnect the battery completely when trailer is in the storage yard and top charge battery before putting away in storage, and then top off battery with distilled water as necessary after charging up for storage.
I am running a true commercial grade deep cycle battery, no calcium in solution in the plates, antimony instead and thick, thick lead plates. About 90# worth of battery for 150 amp hours. All those little things add up, if you are a purist, or an electrical engineer, or an electronics geek.
For small scale 12V stuff at 240 watts or less, I prefer portable solar panel set ups over fixed,mounted on the roof. Far more harvest and efficiency any time of year if you aim them and chase the sun a little bit. Means also owning less panels and less up front cost,because so much more efficient when portable, higher yield in amp hours per panel.
If I sell my travel trailer and upgrade, my portable solar panel comes with me, not lost in the sale to someone who may not care to use solar in the first place.
