Forum Discussion

MisconductOIB's avatar
Feb 26, 2016

Solar Adventure

Well since I'm going to be boondocking some this summer I have decided to begin my SOLAR adventure. I plan on buying my batteries this weekend. Starting off with 2 6V batteries any advice on manufacturer and such.
  • Go over to the Tech forum and search solar. You'll be there all day.
  • Your RV will consume more power than most 'guess'. The CO meter, propane leak detector and refrigerator together consume about 35 amp hours per day, or what a 120 watt solar panel will put back in a normal day.

    I would recommend a pair of 140 watt solar panels, and a PWM controller. The MPPT are way overpriced for the couple of extra amps that they claim to put into the batteries.

    This place has 12 volt nominal solar panels for $229 with aluminum frames. SunElec.com

    You can use 6" long 2" angle aluminum for brackets, with 3 holes 3/16" for #10 screws into the roof, and 5/16" hole for the 1/4" bolt into the panel framework.

    Rubber roof sealant seals all the holes, and prevents leaks.

    I ran #10 UV resistant grey wire down through the refrigerator vent to the controller, then to the battery.

    Good luck,

    Fred.
  • MisconductOIB wrote:
    Well since I'm going to be boondocking some this summer I have decided to begin my SOLAR adventure. I plan on buying my batteries this weekend. Starting off with 2 6V batteries any advice on manufacturer and such.

    Do any energy audit first this will tell you what size battery bank you will need. Two 6 volt batteries may be fine or the audit may tell you that more are needed. Even though this is a pita it is very important to do.

    Once you know the battery bank size needed then you can figure out what you need in the way of solar panels.
    The nest and it's loads
    The link I've included is the way I went about it. There are many others here also.
  • I bought a pair of Sam's Club 6V GC2 Energizers, three or so years ago. They are holding up well, have been lightly used, and have been on solar since new.

    Solar does a better job of charging than I can with all manner of 120V chargers.

    I'd suggest you have an upgrade path or buy more module than what you need, initially. A solar user seems to find new ways to use that power.:)
  • Stop. Do an energy audit.

    One good way to do this is to plug the entire rv into a kill-a-watt meter and measure a couple of days of energy use. Here is a simple flow chart.

    Budget-->Energy Audit-->Battery bank size-->number of watts-->PWM or MPPT. What ever type of controller is chosen, make sure it has adjustable set points and a temperature probe that is on the battery.

    If you use solar as a battery charger, one rule of thumb is between 60 and 150 watts of panels per 100 amp-hours of storage. The smaller the battery bank the higher the wattage needed (per 100 amp-hours). Here is a link to the rather special spreadsheet which includes an energy audit, that N8GS has created to help size solar battery charging systems!

    solar spreadsheet by N8GS

    If you full time or use an inverter lots, then populate the entire unshaded area of the roof with panels. I'm considering replacing my awning with solar panels.

    For a nice explanation of solar, try this link:

    Golden rules of solar
  • Very good write up Rbertalotto. Got my inverter 3000 watt going to work on my audit next had not thought of that, but makes very good sense.
  • A 3000 watt inverter may make the tiny battery bank pretty unhappy.

    My 3000 Magnum uses about 23 amp-hours per day just by being turned on.

    It does have a sleep mode but then it "flashes" power once every 5 seconds and I dislike the various idiot lights and beeps from occurring.

    MisconductOIB wrote:
    Got my inverter 3000 watt going