
This blog post is going to teach you how to add an Inverter, Alternator charging via DC-DC Charger, and Solar charging to your OEM camper or RV that came factory installed with 30 amp shore power hookups.
This diagram features:
- 3000W Inverter Charger
- 400+ Amp Hours of Battery Storage Capacity
- 400W-1200W Solar Array Capacity
- Alternator Charging
- Shore Power Charging/Passthrough
Not quite what you are looking for? Check out other system setups here: https://www.explorist.life/solarwiringdiagrams
TABLE OF CONTENTS
History of Changes to this Page (Click to Expand)
Published: September 8, 2020 – Any changes made will be listed above.
HOW TO USE THIS PAGE – VIDEO
This orientation video will show you how to best use this page to build your DIY Camper Solar Setup. It’s a quick watch but I think it’s pretty important.
30 Amp OEM Camper Electrical Upgrade Wiring Diagram

30A Camper Solar Parts – Shopping List
The list below is a consolidated parts list for this entire system (Minus the solar charging leg, which is listed at the bottom of this blog post).
For the ‘Quantities’ in the below shopping list, each singular component is listed a quanty per each, wire is listed a quantity of feet, and heat shrink is listed as qty 1 = 2.25″.
For Example:
Qty 1 – Inverter Charger means you need to purchase 1 Inverter Charger
Qty 3 – 4/0 Wire means you need 3 feet of 4/0 wire. This may mean you need to buy 5ft from the product page
Qty 5 heat shrink means you need 5 pieces of 2.25″ heat shrink. This means you’ll need 5 x 2.25″ pieces of heat shrink for a total of 11.25″ of heat shrink.
30A Camper Solar Parts Detail
The section below will tell you where each of the parts from above fits into the wiring diagram. This is quite lengthy, but if you are having trouble seeing the diagram or just want more clarification that the diagram above doesn’t deliver, hopefully this will help:
Solar Charging Parts List & Wiring Diagrams
The following section provides you with several different options for solar charging. The above parts list can remain completely unchanged and the diagram above can remain mostly unchanged except for the alterations noted by the diagrams below, but whatever solar array setup you choose below for your needs, these parts will need to be added to your shopping list. These are broken up by total solar wattage. As a general rule, you want to have twice as many watts of solar as you do amp hours of batteries. So, 300Ah Batteries = 600W solar. 400Ah Batteries = 800W solar. 600Ah Batteries = 1200W of solar. This is just a rule of thumb. Not a law.
400 Watts – 4x100W Solar Panels – 12V Battery Bank (Click to Expand)

600 Watts – 6x100W Solar Panels – 12V Battery Bank (Click to Expand)

600 Watts – 3x200W Solar Panels- 12V Battery Bank (Click to Expand)

800 Watts – 4x200W Solar Panels- 12V Battery Bank (Click to Expand)

1000 Watts – 5x200W Solar Panels- 12V Battery Bank (Click to Expand)

1200 Watts – 4x300W Solar Panels- 12V Battery Bank (Click to Expand)

Typical 30A RV OEM Wiring
Here is a quick look at how MOST stock OEM RV’s are wired:

- The diagram above shows the typical bare-bones OEM RV/Camper with 30A shore power service.
- Shore power flows into the breaker box, powering the breaker box protected by a 30A breaker where 120V AC power is then distributed to the various circuits.
- One circuit is generally the Converter. The converter is usually built into the same enclosure that houses the breaker box (as shown) but is sometimes external. Either way, it’s wired in the same method.
- The converter converts the 120V AC power to 12V DC power which feeds the DC Fuse Block which powers the various DC devices around the camper (Lights, Fans, Etc..).
- From there, a positive and negative wire continues on to the house battery bank; usually two 12v batteries wired in parallel. These wires charge the batteries from shore power, and allow 12v devices to run when not connected to shore power.
- At the batteries, there are usually 2+ additional positive and negative wires heading off under the RV somewhere that are going to power additional DC circuits around the camper. These may be slide-outs, powered leveling jacks, and other ‘chassis’ items like that. These wires will likely have fuses in line to protect these wires coming from the battery.
- One of these wires is also likely the wire coming from the alternator to charge the house battery bank.
- When the camper is NOT plugged in to shore power, all of the 12V DC appliances will run due to them still being connected to the batteries, but the 120V AC appliances will NOT operate because the converter is a one-way-street and will not convert 12V DC back to 120V AC. The charging from alternator is typically very slow (less than 10 amps) and should, generally, not be relied on to provide adequate power for recharging deeply depleted house battery banks.
How to Integrate a DIY Camper Electrical Upgrade with the OEM Wiring
In addition to wiring the components together, here is a breakdown of how the flow of power to the above diagram works.
WIRING THE INVERTER/CHARGER To Shore Power.
When connected to shore power or generator, power flows from shore power (or generator) to the Victron Multiplus inverter charger. This charges the batteries which feeds the DC fuse block and allows 30A shore power passthrough to power the 120v appliances. You will take the 10/3 wire that goes from the shore power inlet to the back of the AC distribution panel and instead, run that wire from the shore power inlet to the input of the Victron Multiplus.
Wiring the Inverter/Charger AC Distribution Panel
The wire from the Multiplus Inverter/Charger to the AC Distribution panel should be replaced from the 10/3 OEM installed wire to a 6/3 wire and the 30A main breaker should be replaced with a 50A main breaker to accommodate for the additional capabilities of the Victron PowerAssist function.
Wiring the Solar Panel Array to your Camper Electrical System
When charging from solar, the solar panels & charge controller charge the batteries. The batteries are connected to the DC fuse block allowing use of the 12v devices around the camper. The Inverter takes the 12V DC power stored in the batteries and converts it to 120V AC power to power the 120V AC items around the camper.
Replacing Stock Camper Batteries with Busbars
A positive and negative busbar take the place of the stock batteries in the stock battery location (assuming that upgrading batteries means you will not be able to store your new battery bank in the stock location). From the Lynx Distributor, power flows to these two busbars where power is then sent to all of the OEM installed components like the DC distribution block, power jacks, slides, etc.
30A Camper Converter
The OEM installed converter must be completely disconnected. It can remain installed, but the wires must be disconnected from both the AC and DC side of the power distribution center. These wires can usually be bundled up and stuffed next to the converter.
30A Camper Alternator Charging
You will likely have a wire charging your OEM batteries from the alternator. This wire will likely be somewhere in the 12 AWG range. This will either run directly from your starting battery isolator if this is a motorhome or from your 7-pin connector if this is a trailer. This needs to be disconnected completely. This diagram uses a 30A DC-DC Charger and the OEM installed wire will be too small. The 6 AWG wire in the diagram will take the place of the OEM wire you are to remove. In the case of a trailer, 6 AWG wire will need to be run all the way to the truck starting battery if alternator charging via DC-DC Charger is desired and disconnected by the hitch by means of an Anderson connector.
Matt
Monday 18th of January 2021
Nate, what's the max length the between (4 BB) batteries and the Victron Multiplus Inverter Charger 3000 W 12 V? To fit on the TT the best I really need to separate them by 15ft or so. Is that too far?
Thanks
Matt
Tuesday 19th of January 2021
@Nate Yarbrough, that's a bummer. Time to reconfigure :). Thanks
Nate Yarbrough
Tuesday 19th of January 2021
15ft from batteries to the inverter is indeed too far per pg. 8 of the Victron Multiplus user manual: https://www.victronenergy.com/upload/documents/Manual-MultiPlus-3k-120V-(firmware-xxxx4xx)-EN.pdf
Ken
Wednesday 13th of January 2021
Normal Voltage Drop
Under a load of 130A, I have a voltage drop of about 0.4 volts from battery bank to multiplus inverter. Normal?
The battery bank was at 12.4 volts and the inverter at 12.0. The respective voltages (from inverter tracing back to battery bank) were: 12.00 at inverter, 12.10 before Lynx Distributor, 12.13 before on/off, 12.30 before ANL fuse (biggest loss by far) and 12.4 at bank.
Under progressively heavier loads my inverter shut down due to the low voltage cutoff (currently at 11.5).
Ken
Wednesday 13th of January 2021
@Nate Yarbrough, also, yes I am using the Blue Sea fuse holder as recommended (and also used the high quality 4/0 cable and terminals you recommended).
Ken
Wednesday 13th of January 2021
@Nate Yarbrough, currently I have a "Boamain" fuse installed (probably junk) and am waiting on Amazon to deliver my Blue Sea ANL Fuse (400A). Hopefully that fixes the voltage drop across the fuse.
I will double check all other connections.
Nate Yarbrough
Wednesday 13th of January 2021
12.4V to 12V is 9.6% voltage drop is at the high end of normal (Anything under 10% is acceptable), but it's still higher than expected (I would expect under 3%) for this system. I would recommend going back and checking each and every bolt in your system and making sure they are all tight and that you do not have any loose connections.
Also, seeing as the biggest voltage loss is at the ANL fuse... Just verifying... but you are using high-quality Blue Sea fuses & fuse holders as specified in this diagram and parts list, correct?
Matt
Saturday 9th of January 2021
Nate, Thanks for all the great information. I purchased one of your wiring diagrams for an 30amp RV set up. I am going to start with 4 BB 100 amp hr batteries and 4-6 solar panels. And after looking at your site and many of the videos I am understanding most of the install. I am having trouble understanding where the Victron Orion Smart 12|12 - 30A wires to on the vehicle battery side. Does it just connect into the trailer 7 pin wiring harness that connects to the truck?
Matt
Sunday 10th of January 2021
@Nate Yarbrough, Thanks, I think I may leave that out to start with. Then see if I need after I use it for a while.
Nate Yarbrough
Sunday 10th of January 2021
That needs to actually be connected to the starting battery of your vehicle. Yor 7 Pin connector likely only uses 12-14ga wire, which is too small for this increased load. Make the connection for the new 6 AWG wire from truck to trailer with an anderson connector: https://amzn.to/3bpUUJL
Ken
Friday 8th of January 2021
Thanks for all your content, Nate. Its simply awesome!
Few questions:
1. Grounding: my 30A travel trailer already has grounding at the breaker box (presumably it leads to chassis). I installed a full inverter/solar system following your diagram and grounded the Lynx Distributor directly to the chassis with 4/0. Do I need to remove the original grounding points at the breaker box, or is it okay to ground to chassis at multiple points?
2. Alternator charging: I have a traditional 7-pin connector that I believe provides minimal charging from my truck alternator to travel trailer while driving. My system does not include an isolator or additional alternator charger (it looks identical to the system you installed in the Airstream). I don't need alternator charging, but I just want to ensure my setup will not damage my truck alternator. Do I need to add any protection? Or take any steps to isolate the truck?
Thanks Nate!
Ken H
Tuesday 12th of January 2021
@Nate Yarbrough, any recommendations on how to identify the alternator charging wire?
Nate Yarbrough
Saturday 9th of January 2021
1: There can be multiple DC grounding points.
2: It would be best to simply disconnect the alternator charging wire from your battery bank in that case.
Larry Volenec
Thursday 31st of December 2020
Nate,
Great job with the website and providing kits for power system installs. I have a question regarding the Victron Multiplus 3000 boosting inverter. Once or twice a month (we leave the inverter running almost constantly), the inverter will buzz very loudly. I have tried shutting off all the AC breakers, one by one, to see if it will stop and that has no effect. Turning the inverter off and on from the Victron Multi Control stops the noise while the inverter is off, but the buzzing noise starts back up when the inverter is turned back on. The loads on the inverter are very low when this occurs. Normally the inverter hums a little when under load, but the buzzing is very loud and annoying. It tends to go away on its own after 20-30 minutes. The installer said that happens with non linear loads occasionally. Below is a list of components for my installation. Have you run across this ever? Thanks for your insights.
Component List 400Ahrs Victron Lithium batteries 2-200Ahrs connected in parallel 3000w Victron Multiplus boosting inverter charger (all AC loads pass through the inverter) 720w roof mounted solar 4 -180w panels connected in parallel 50a Victron charge controller for the solar panels Victron Color Control panel Victron Multi Control remote inverter controller Victron BMV-712 Smart Battery Controller Nations 280A Alternator and Balmar voltage regulator (4000W Onan generator was removed) AM Solar Battery Management system
Nate Yarbrough
Friday 1st of January 2021
Something definitely sounds wrong with the inverter. I would recommend reaching out to the place you purchased the Inverter from and see if this may be a warranty replacement issue or something. The inverter will buzz under certain loads, yes; but should stop as soon as the load is turned off. For example... my heat gun when on the 'low' setting makes the inverter make noise; but as soon as I turn the heat gun to off or 'High', the noise goes away.