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dewey02's avatar
dewey02
Explorer II
May 08, 2017

Portable Solar being set up - Please check my plans

I will be installing a portable solar system and want to check with folks to see if the set up I have planned is correct. While this will be a home-built portable unit, I will be installing an electrical sub-panel inside the trailer (in the pass through) that the panels will connect to.

Our Situation:

We will NOT be installing panels on the roof, just a portable unit. We camp mostly in tree-covered areas. Our electrical use when camping is fairly minimal. I have replaced all lights with LEDs. We do not have (or ever intend to have) a television nor do we plan to use the microwave when boondocking. We do use an iPad, and a laptop that we use which will need to be recharged. We play the radio about 2 hours per day. We have the propane/DC refrigerator, toilet fan, kitchen exhaust fan, and two O2 Cool 12 volt window fans, and of course the water pump, and CO/Propane detector. We do camp when weather gets cold, so we use the propane/DC furnace in the fall.

What I have already purchased and will be using: (we will not revisit this as it is already purchased)

  • Two 120 Watt 12 volt semi-flexible solar panels from Solar Blvd. I have built aluminum frames for each of these and they are connected like a solar suitcase. They are 12 volt (Vm 20V; Im 6.0A; Voc 22.8V; Isc 6.65A). I plan to run them parallel to keep voltage at 12 volts. I am using semi-flexible panels because of the great savings in weight vs toting around glass panels of equivalent wattage
  • Two Energizer 6 volt golf cart batteries wired in series. 215 amp hours. Connection between the two batteries is 4 AWG wire. I’ve had these for two years now.


I plan to purchase the following from Amazon:

1. 30 ft of 8AWG wire with C4 connectors. Is this an adequate length? And is the gauge large enough? Or can I go with a smaller gauge and save some money? Link Here

2. Renogy CNCT-MC4Y Branch Connectors Solar MC4 Connectors Y connector in Pair MMF+FFM Link here


3. Grape Solar GS-PWM-40BT 40 Amp PWM Solar Charge Controller with Remote Monitoring (I intend to us my Apple iPad’s Bluetooth to access the remote monitoring). I plan to mount the controller in the pass through at the front of the travel trailer. Link here

4. Battery Minder EZ Connector. This will be the plug in to the side of the trailer and will connect/disconnect panel wires from controller. Wire size for this is 12AWG, but I will be only using these wires for very short distance (less than 1 foot).
Link here

5. Two RadioShack Gold-Plated Inline Fuse Holder with 40 amp fuses. Link here



6. Wiring run from Controller to Batteries – need help with gauge here. The run will be approximately 3 feet. What size wire should I be using?

7. Do I need a battery cutoff switch? Between which wires do I install it? What brand/type?

I don’t plan to install an inverter at this time, but will pre-wire the elect. Sub panel for the future.
I would appreciate your critique of the system and suggestions for wiring sizes, improvements, etc. Please avoid the “put it on the roof” and the “semi-flexible panels suck” comments, as those decisions are already made. I have numbered the items that I have not yet purchased, so that you can easily refer to each item. Thank you in advance.

73 Replies

  • I have no trouble with stranded #8, but perhaps there are other kinds.

    Distance of ground based panels from trailer.
    ------

    Besides anything else in the way, the trailer itself is a problem for shading the panels. You want to park with the battery bank to the South to keep the panels close facing South, but this may not be possible. If the batteries are facing North, your panels will be at the other end of the trailer--how long is that?

    Usually with the panels out to one side of the trailer, at some point the sun goes around the other side so you have to move the panels. Your awning and slide being out make this "worse" so that means even farther out from the trailer.

    Here we are in a field with only the trailer in the way-panels about 40 ft South of the trailer. Got sun until just before sunset when the back of the trailer gets in the way, but by then the solar has done its job. Panels in a twirling contraption I made.



    You should be ok with about 40 or 45 ft distance from the trailer NOT COUNTING trees or where some other guy's trailer is.

    Campground site--you can't set the panels up in the next guy's site. That and other things can make it all very awkward. But it can be done--just pick your own site carefully, looking at all the sun directions etc etc.
  • I can not image how stiff & tendency to kink 8g 'solar' wire might be.

    10g is stiff enough! Not suitable for portable IMO.
  • I don't know if 30ft is enough - probably cutting it close if you're a tree camper. I'd consider putting those panels in series if you go longer to cut down on line loss. Your controller will handle it.

    I don't see the need for fusing panels; some do.

    If series you can eliminate #2. Size #6 to whatever an amperage chart suggests.

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