Our  latest RV is a 2007 Ford Transit Van, extra long wheel base – we bought it as an empty shell (an ex work van) and we completely outfitted it with  cabinets, drawers, wardrobe,  bathroom, kitchen, dining and a bed!

For the 12 volt electrical, we added a 105 amp hour deep cycle AGM Battery , a 150 watt  RV Solar Panel, RV Led Lights, Water Pump,  12 volt Television , 12 volt Sockets and USB Charger.  I’ll attempt to show show you how all of this was done.

I bought a BEP 1000-6w  RV switch panel with built in fuses , that way I didn’t have to buy a separate fuse panel which saves on space and wiring.   I also bought a 150 watt   Mono Crystalline  RV Solar Panel which puts out about 8 amps in full sun.  With this I also bought a Top Ray TPS 1230 –  30 amp RV Solar Controller which regulates the power from the Solar Panel.  In the photo below I’ve attached the RV Solar Panel to the roof of the van with some ABS brackets  which are screwed to the roof  and sealed with Dicor Sealer.   You could use metal brackets which are a lot  cheaper than ABS,  however I think the ABS brackets look better and they won’t corrode.

The RV Solar Panel came with a 10′ cable,  I drilled a hole through the roof underneath the solar panel and ran the cable through it, I then sealed around the hole with Sikaflex.  I left a bit of slack in the cable so I can occasionally lift the solar panel and clean underneath it.

RV Solar Panels need an air space underneath for cooling, about an 1 1/2” is enough.  RV Solar Panels work better when they’re cooler.

Solar panel on van roof.

150 Watt Monocrystaline Solar Panel.

To make the project neater, cheaper and easier I’ve mounted the Battery , the Switch Panel and the Solar Controller all very close to each other.   The Switch Panel ( pictured below) is mounted on the outside of a closet wall and the Solar Controller is mounted just behind it on the inside of the closet and out of sight. The  RV Battery is also inside the closet, mounted on the floor.  Having these items close together uses less cable, makes the job cheaper and you get less voltage drop with shorter cables.   Also if you have a fault in the system it will be easier to fault find if most of your connections are in the same area.

Bep 6 Switch panel, with built in fuses

Switch Panel made by BEP with six switches and and six built in fuses.

The cable from the RV Solar Panel enters the rear of the closet to attach to the RV Solar Controller.

30 amp solar controller.

30 amp RV Solar Controller mounted inside closet

The photo below is a close up of the RV Solar Controller,  most RV Solar Controllers have the same set up.  There are 3 sections, the left hand section has a picture of a solar panel, the middle section has a picture of a battery and the right hand section has a picture of a light bulb.  Each section has two screws, one for a (positive +) cable and one for a (negativ e -) cable.  Notice that I have run the red cables to the + and the black cables to the – , or red to positive and black to negative.

So basically my RV Solar Panel cables attach to the left hand section , my battery attaches to the middle section and the right hand section  will power my 12 volt led lights, RV water pump , TV and 12 volt outlets.  The ends of the cables will need some insulation removed to fit the terminals in the solar controller.  The RV solar panel cables need to be attached last, after the battery cables are attached for safety reasons.

 

close up of solar controller wiring terminals

                                                 Close up of my Solar Controller showing the three different sections of the wiring set up. solar panel, battery and the load .

OK that part was simple, now I’ll show  you how to set up your 12 volt circuits,   From the right hand side of the RV Solar Controller, or the load side,  I’ve run the red positive + cable  to the Positive Bus Bar, and the black- cable to the Negative Bus Bar.   Now I have  positive and negative bus bars,  just like two live battery terminals.  I keep the bus bars separated because if a conductor  touches both bus bars at the same time i’ll have a short circuit.  Bus bars like the one in the photo below are great because you can easily add circuits without  crimping on eye terminals and running multiple cables from your battery terminals.   It would pay to mark + next to your positive bus bar and a – next to the negative bus bar to save confusion.

So now the battery voltage will travel from the battery to the RV Solar Controller then down to positive and negative bus bars.

Electrical bus bar.

This a the “Positive” Bus Bar for running multiple circuits, there is a similar Bus Bar for “Negative”

Using a couple of Bus Bars can reduce the amount of cable and crimp terminals needed, as well as produce a neater and more reliable job.  The photo below shows the rear view of the BEP RV 6 Switch Panel and below it is my Positive+ Bus Bar.  The short cable with the  yellow insulated eye terminal is the power feed into the switch from the bus bar.  From there the current travels through each of the 6 individual  switches and out through the 6 red wires to the left, running to each of the 6  circuits.

Rear of Switch panel

Rear of BEP Switch Panel.

When running your cables,  buy some twin sheath insulated cable similar to the photo below and run a separate length to each RV light fixture or appliance.  Make sure your cable is rated high enough for the circuit.   Note: the switch panel I’m using comes with 5  ten amp fuses and one 15 amp fuse so if you have circuits that require more amperage than that  you may have to run though a relay or use a heavy duty switch.

 Twin Sheathed Insulated Copper Cable.

 When running your cables don’t let them  rub on any sharp edges, you don’t want a short circuit and don’t run 12 volt cables across 110 volt cables if you have any.  When attaching to pumps and lights etc, strip some insulation from the cable ends and attach red to red and black to black, using crimp terminals.  If your using LED lights, the wires coming out of 12 volt LED lights are sometimes white and black, if this is the case run black to black and red to white.  Note: if you wire 12 volt LED lights backwards they won’t work.

At the other end of the cables run them to your switch and strip about  5/16  of insulation from the ends of the red and black cables.   Attach the red cables into the rear of the RV Switch Panel as in the photo below and tighten the retaining screws.

The black cables will attach to your Negative Bus Bar with the black wire going to it, not the Positive Bus Bar.

Power travels from the Bus Bar to the switch then to the 12 volt appliance

I used up all 6 switches of my RV Switch Panel on lights, TV and the water pump, and I still wanted a 20 amp 12 volt socket with USB outlets.  Now even if I had room on the switch panel for the 20 amp socket,  that’s too much amperage for the switches and a 12 volt socket does’t really need a switch .  To add an extra circuit,  I bought an Inline Blade Fuse Holder,  pictured below,  and instead of using a fuse I’m using a 20 amp blade style breaker.  They cost a little more but you don’t have to buy another one if it blows.

I attach one cable from my Inline Fuse Holder to the Positive Bus Bar then I add a length  of  red 12 AWG Cable to the other cable coming from the fuse holder,  long enough to reach my 12 volt socket.  That cable has to attach to the positive terminal inside the 12 volt socket.   From the negative side of my 12 volt 20 amp socket I ran some black 12 AWG Cable back to my Negative Bus Bar.

   Inline Blade Fuse Holder with 20 amp breaker

If I had a few extra circuits to add I would probably buy an extra fuse panel,  however if it’s only one or two extra circuits, Inline Fuse Holders are inexpensive and easy to install.

20 amp 12 Volt Socket with USB Chargers

I have a small inverter, only 300 watts, and I connect it directly to the battery with the supplied alligator clips, cables and inline fuse.  Inverters need to be mounted as close to the battery as possible,  with the shortest cables possible and with the appropriate size fuse, shorter cables mean less voltage drop.   Inverters draw too much power to run through the RV solar controller.

Inverter is connected directly to the Battery with eye terminals or alligator clips

The battery I used is an AGM which stands for “Absorbed Glass Matting”.  Some of the wonderful advantages of AGM  Batteries are that they don’t need  topping up, there are no filler caps or plugs.  If they fall over nothing leaks out and they are great in an RV  because you don’t get any gas smell and they’re maintenance free!

105 amp Hour Battery with 8 AWG Battery Cable

                                                                                                        

The Positive+ Battery Cable runs to a Fuse then up to the Solar Controller

I’m using  8 AWG Cables to run from the battery  to the RV Solar Controller.  From the Positive+  terminal of the RV battery, I run a short length of red cable to a main fuse  or a breaker as in the photo above.  The black Negative-  cable goes straight to the Solar Controller.

The RV Solar Controller I’m using is rated at 30 amps  input and 30 amp output, I can have up to 360 watts of solar panels with a Solar Controller that size although my solar panel is only 150 watts.  By taking my power from the 30 amp RV Solar Controller I can only draw 30 amps, if I draw too much amperage the RV Solar Controller has a built in circuit breaker that will cut out which is very handy as it saves blowing fuses.  The RV Solar Controller will also cut power if the battery voltage gets to low which protects your battery from over discharging.

The AGM  Battery is totally separate from the vehicles starting battery, it only receives a charge from the solar panel.  By setting it up this way there’s no chance of flattening your vehicles  starting battery while camping.   If in the future I find that the solar panel isn’t charging fast enough I could also charge from the vehicles alternator but for now I think this is working perfectly!

The 150 watt RV Solar Panel is perfect for our system, however we are  using a gas fridge.   If we we’re using a 12 volt compressor type RV refrigerator we would probably nned to double the solar capacity and add another battery.