Originally Posted by rpatterson
A fully charged deep cycle battery should not go down in 3-4 days. I even have a 2 watt solar trickle hooked up.
I think your expectations might be aimed a bit high. To keep your battery healthy, you don't want to draw them below 50% SOC. A true deep cycle 12v battery (as opposed to a deep cycle RV/Marine hybrid) would typically have 180-220 ah capacity. So you'll half that to 90-110 ah "available". Parasitic draw ALONE will eat that up in 3 days. Throw in some lights, water pump, cooking stove ignition, hot water heater, reefer... you would have to be conservative to get 2 days let alone any longer without a charge source. Generator, alternator in your TV, solar... whatever your poison.
A 2 watt panel.. which you will rarely see outputting the full 2 watts will only get you around .35 amps (1-2 amp parasitic though).
So realistically you would need a good 2-3 hours of maximum output from your panel to run a single small LED like for an hour. As a trickle charging system, you'll be loosing 3-6 times more juice just from parasitic draw than your panel is capable of adding to your battery.
Solar is certainly a good option though. I run a 440ah battery bank on 540 watts of high voltage panels with all the creature comforts (microwave, TV and Satellite receiver, etc) and only on very rare occasions have to crank on my genny to recharge. In winter maybe every other week and with summer sun it may only be once during a three month period.
You're headed in the right direction though.
I just remembered. Isn't that 2watt panel 6v?