These are the items we will be installing on our 28 foot Class C RV: Total cost is roughly $2750

- Solar panel (4x150 watt Hightec) = 600 watts

- Battery controller (Morningstar MPPT 60 amp)

- Battery bank (4x6v Trojan T-105RE) = 450 amp/hr @12v

- Inverter (2500 watt Sunforce PSW)

- Battery monitor (Bogart TriMetric 2030)

This is how I was thinking I would install the system:

Solar panels —> Charge controller

On the roof, I will mount the solar panels on a single frame that will be able to be tilted two ways (towards the driver side or the passenger side). There are no shadow issues that will come from the RV itself as long as we are parked facing north/south in the summer and east/west during the winter. We will wire the panels in both series and parallel so we will essentially have two 300 watt panels providing 24v of electricity down to the charge controller. The wire we will use to connect the panels with the controller will be a 6 gauge AWG copper wire.

Questions:

1) Do we need to wire through a junction box or any sort of fuse before the electricity makes it to the controller?

Charge controller —> Battery bank

I will mount the charge controller in the same sub bay (basement) compartment as the battery bank roughly 22 feet of wiring away from the pannels. There will be a ventilated door to this compartment and the batteries will be on stands/holders that allow them to stay separated and breath. The controller will be mounted roughly 2 feet away from the bank of batteries. I will use 2 gauge wiring to connect the controller to the batteries.

Questions:

2) Is there any issue with having the controller and the batteries in the same compartment?

3) Do I need a fuse wired in-between the controller and the batteries

Charge controller —> DC fuse box

Our current DC power is run off of a 75 amp/hr marine AGM battery that is charged by a power converter that was already installed in our RV. The power converter is plugged into a standard outlet where it draws the AC, converts it to DC, and then gets wired into the fuse box that is directed to the house battery (I’m assuming this is how the battery gets charged). From there, I believe the battery is routed back to the fuse box where the power is distributed to all of the DC appliances. I would like to keep this system for our DC power but I don’t necessarily have to. I was thinking what I could do is direct wire from the charge controller to the fuse box to replace the DC charging power provided by the power converter. When the inverter is turned on and we are drawing AC from the solar system, we will have the power converter unplugged because it will be unnecessary due to the direct wiring from the controller.

Questions:

4) Are we able to direct wire from the controller to the fuse box to charge the current house battery DC system?

5) Should we leave the converter plugged in and not direct wire?

6) Does there need to be a fuse between the controller and fuse box if we do direct wire?

7) Is there a better way to wire for DC power form the solar setup?

Battery bank —> Inverter

I will wire the batteries in series and parallel to produce a 450 amp/hr bank @12v using 2 gauge wire. I will also use 2 gauge wire to connect the batteries to the inverter. The inverter will be located just inside the door of the RV. This will be roughly 4 feet from the batteries and only 3 feet from the AC breaker box. 

Questions:

8) Does there need to be a fuse or anything wired between the battery bank and the inverter?

Inverter —> AC breaker box

From what I gather from online diagrams, I will directly wire the inverter to the main breaker.

Question:

9) Should I wire this using 2 gauge wire or something smaller (higher gauge)?

Additional questions

10) Where do we install the battery monitor? Do we need a shunt? If so, what size (100amp/500amp)?

11) How do you set the charge controller to charge the battery bank at 14.8v?

12) Are there any items that we haven’t planned for or are there any additional suggestions you may have?

I have kind of hit a road block with my research for this installation so any help or suggestions would be greatly appreciated. If there is anything that I failed to mention in this post, please feel free to ask and I would be happy to provide those details.