Forum Discussion

Ev2210's avatar
Ev2210
Explorer
May 15, 2013

Solar power

We are thinking of getting a solar panel to use if we ever dry camp. Any thoughts on what size etc. The longest at any one time would be 2 days. Do we just need the panel or do we require other items to go with it. Completely new at this, so don't want to get hosed buying unnecessary equipment. Our TT is a 28". We would use it mostly for lights and maybe running the TV for an hour in the evening.
  • Though I have solar and love it, I don't think it would be worth the investment for you. We are aff the grid from 5-7 days at a time. With 2 days max, I think you would be just fine with 2 batteries. If you only have 1, add a second. You should be able to run everything you need for 2 days with 2 batteries..

    Dave
  • RoyB's avatar
    RoyB
    Explorer II
    My thoughts on adding a solar panel is to just enhance my battery system when camping off the power grid.

    My off-road popup camping includes smart mode converter/charger, additional batteries, several "go Green" ideas including LED lights, small inverters, etc...

    All of this allows us to camp off the power grid and run all the 120VAC and 12VDC things we want to have with us for a couple of weeks. The game plan here is do all of these things we want do in an one day/night camping experience and then be able to re-charge the batteries back up to their 90% charge state the next day in as short of time as possible.

    I will run down my 255AH battery bank to around 12.0VDC the next morning and then connect the trailer shore power cable to my 2KW Hinda generator using a RV30A-15A long adapter cable. This will allow my on-board smart mode converter/charger system re-charge my battery bank to its 90% charge state in as little as three of generator run time. The nature of the deep cycle batteries allows you to be able to get full specified battery power with just being charged to the 90% charge state without doing damage to the batteries.

    You also have to be aware that you can only do these 50% to 90% charge cycles for only a limited number of times before needing to re-charge to to a full 100% charge state to re-new the battery core plates.

    To not do damage to the deep cycle battery bank I will need to do a complete 100% charge state about every 10-12 days which will take a good 12-hours or more using smart mode charging technology. Normally this would would require running your generator for that total time period which alot of places will not allow you to do. Also My 2KW gasoline tank tank will only run about 7 hours so would have to be re-filled. It doesn't just seem right to have to run a generator for that long of time to get a 100% charge state on your battery bank. We usually just plan our camping off the power grid trips to be around the 10-12 days and then re-charge our batteries back to their 100% charge when we are are back on shore power.

    Where I think the solar panels would work great for me is during the day light hours I can use at least 120WATT solar panels to provide additional trickle charging of my battery bank between the time I am allowed to run my generator which is usally a couple of hours in the mornings and then again for three hours more in the early evening.

    What I would hope for is that solar panels would bring my Battery banks back up to a batter charge state and maybe I wont have to run the generator as much to do the 50% to 90% charge states.

    In my way of thinking the solar are only to used for storing up power as the sun is only out during the daylight hours and what power you have captured has to be stored in the batteries to do you any good when you need to use the power.

    My camping off the power gird planning was to beef-up my trailer equipment first for smart mode charging technology, changing out the incandescent automotive high current bulbs for leds, beef up the battery system to run all of the 120VAC and 12VDC items we want to run when camping and finally be able to re-charge the battery bank back up to its 90% charge state so that we can do all of this all over again the next day/night camping experience from the batteries.

    Camping off the power grid with just solar panels IMO is not the only thing you will need to have with you. You will need to store this captured energy from the sun to be able to use through the one day/night battery run. To me having the capability of re-charging my battery banks with a 2KW Honda type generator is the first must have item as this will work whether the sun is out or not. having solar charging will only work when the sun is out. It will not do very well if it is cloudy and rainy for several days...

    I have to have my PLAN Bs in place to be successful...

    Just my thoughts on using solar panels.
    Roy Ken
  • First, determine what your power usage might be. Lights, water pump, fan, gas detector, refridgerator, furnace, television, radio, etc. Keep in mind, on a cool night, your furnace could put a heavy drain a single 12 volt battery, and your solar panels give you nothing in the dark. Changing all the light bulbs to LED's, will cut lighting power usage, by about 70 percent.

    Approximately 250 watts solar output, 30 amp controller, and a battery bank big enough to handle your power usage. Wire runs should be short as possible and done with 10 - 12 gage stranded copper wire.

    What I have:

    Two 128 watt (24 volt) panels
    Two group 24 batteries
    30 amp MPPT controller

    The MPPT controller takes up to 48 volt input, and, converts it to 12 volt output.

    If you go with PWM controller, your panels must be 12 - 18 volt. Many panels state they are rated at 18 volts, but, actual output is more like 14 volts, which is fine for charging your batteries.
  • Unless you go very overboard with panels, you may be wasting money.I would go with a generator.The last few panels ThatI worked with did not measure up to their rated output.The ones at Harbor Freight were as much as 40% off.