I am excited (and relieved) that our bus has electricity flowing throughout its circuits. Designing, spec’ing components, and building the house electrical system has been a challenging undertaking. In fact, this task has probably been the most complex part of our bus conversion.
Nearly nine months ago, I started reading every article, blog, and forum I could find about RV and converted bus electrical systems. This early information helped me formulate some ideas about the basics of the best electrical system for our specific needs. One of the most important things I learned is that there is no one perfect system. Certain basic electrical design and safety factors must be included in every RV electrical system; yet, there are unlimited customizations available.
I began the design of our system with three non-negotiable guidelines:
- 120V AC would be the primary power source for lights, appliances, etc
- Power would derive from three sources: house batteries, shore power, and generator
- The system must be expandable to include solar power at a later date
Another very important driver of the design was budget. My goal was to design an effective and efficient electrical system on a reasonably low budget. Our budget was $1200 and we came in just over $1000.
In addition to the dozens of hours I spent reading and learning about RV electrical systems, I have a solid understanding and knowledge of electricity. I am by no stretch an electrician; however, I have years of experience doing a wide range of DIY electrical projects. This experience came in handy on numerous occasions.
Fairly quickly in the research and design process, I realized that specific components and equipment impact the overall design. In other words, I learned that I could not design a system and then select components. It was best to let the research, design, and component selection process, move down the track together as opposed to separately. For example, when I determined that I needed a three-way switch to select the source of 120V power going to the breaker panel, my research lead me to Blue Sea Systems because they were the only manufacturer that offered a switch with the exact functionality I wanted. The specifics of the Blue Sea switch (8366) required me to slightly alter my wiring plan. This was an easy modification at this point in the process; but it would have been challenging to make the change later.
Another important design consideration was to keep the house batteries and the engine batteries separate. We will be boondocking as much as possible (and relaying on inverted battery power). The thought of dead engine batteries while camping in a remote location scare the hell out of me.
Shore power and generator power were the simplest and easiest part of the overall system. I installed a Park Power 30 amp RV/Marine Inlet on the outside of the bus. This inlet is threaded to provide a secure water-proof power cord connection. Using 10/4 wire (I had the wire in my shop and ignored the red wire) I connected the inlet to a Square D 4-circuit 2-space 70-amp breaker box. I installed one 30 amp circuit breaker in the box. The output from the breaker box goes to the Blue Sea 3-way switch.
The generator will be mounted on the rear bumper of the bus. I ran 10/4 wire underneath the bus from the bumper to the Blue Sea 3-way switch. The generator has not been installed, so I have not tested this part of the system. I will likely add a breaker or fuse where the wire connects to the generator. This will protect the 3-way switch in the event of a short, surge, or some other malfunction.
Battery power is the most complex part of the entire system. After a lot of research, I decided to buy two Interstate 6V deep cycle batteries. For the price, I do not think there is a better choice for deep cycle batteries. These batteries are located in a sealed box located behind the driver’s seat. The battery box is vented with a 1 ½ inch PVC pipe going through the roof. Camco makes a plumbing vent cap that works great to prevent water from entering the vent pipe.
Battery output goes to a 1000 watt pure sine inverter. Selecting an inverter was a difficult decision. There are numerous pure sine inverters available. Prices and features are all over the map. I eventually selected the NPower XRP inverter offered by Northern Tool. My decision was largely driven by price. I am confident this $250 inverter will meet our needs for a long time.
I installed a Blue Sea Class T 400 fuse block with a 400 amp JJN fuse between the battery and the inverter. I may be over cautious; but, I don’t want to fry the inverter if something goes wrong with the batteries. This fuse costs $30 from Amazon; but, it gives me peace of mind that the $250 inverter is protected.
I used an old 10 gauge extension cord to connect the inverter to the Blue Sea 3-way switch. The extension cord is simply plugged into one of the inverter 120V outlets with the other end hard-wired to the switch.
At this point, there are three power sources going into the 3-way switch – shore, generator, and house batteries. One nice feature of the Blue Sea switch are LED lights that indicate available power. If I am connected to shore power and have the invertor running, the switch shows available power from those two sources.
The output of the 3-way switch goes directly to a 12-circuit 6-space 100-amp breaker box. I am using 15 amp tandem breakers in four spaces. This provides room for four more circuits for future expansion.
From the breaker box, the electrical system is not much different from a typical home. I used 14-2 wire to feed eight outlets and overhead lights.
Originally I planned to switch the inverter input between the house batteries and engine batteries. My idea was to use engine batteries when driving and house batteries when parked. After further research and excellent advice from several skoolie.net users who are much smarter than I am, I bagged that idea. The problem with using engine batteries for the inverter is the distance between the inverter and the batteries. The primary engine battery is under the hood (about twenty feet from my inverter). There is a secondary engine battery located under the bus. Even if I used two gauge wire, twenty feet is simply too far to safely and efficiently power an inverter.
For now, a hard-wired charger is maintaining the house batteries. I plan to add the ability for the engine alternator to charge the house batteries. I am still in the research phase of that addition. Another future addition will be a battery condition monitor panel.
The battery charger is a NOCO Genius G15000. My initial battery charger choice was the Xantrex Truecharge. Those plans changed when Xantrex failed to respond to my telephone and email inquiries. I contacted Xantrex to confirm the charger model I spec’d would meet my requirements. After seven days of no response, I went back to the drawing board and realized that NOCO has several models that would easily meet my needs. I contacted NOCO via email for guidance in selecting the best model. Within six hours, I had a response to my questions. Over the next few days, I exchanged several emails with a NOCO technical support person who helped me make a smart purchase decision. I could not be more pleased with the Genius G15000.
Speaking of great customer support, I cannot say enough positive things about Blue Sea Systems. For the record, Blue Sea is not supporting the Adventurous Wanderers. I am simply a very happy customer. Over the course of several weeks, I had numerous email exchanges with a technical support person at Blue Sea. He offered a level of customer support that is hard to find today.
In addition to the primary 120V AC system, our bus also has several 12V DC components. These include a Winegard satellite dish (great Craig’s List find!), a few dome lights, fresh water pump, and the fan on a Sun-Mar composting toilet (not yet installed.) I wired these components to a central fuse block (Blue Sea ST Blade Fuse Block 5026). This fuse block is powered through a switch that allows either house batteries or engine batteries. The switch is a Blue Sea 11001 Battery Switch. When we are traveling, our 12V needs will come from the engine batteries. When we park, I will switch over to the house batteries. Remember, I fear dead engine batteries in a remote location.
All of the electrical system components (120V and 12V) are located on a panel I built behind the driver seat. This location is easily accessed from the front or the rear of the bus. The bus chassis and engine electrical system is located in a compartment above the driver’s seat. This location made it extremely easy to connect the house and engine systems as needed.
As we embark on our adventure in a few months, I suspect some tweaks to the electrical system will be required. At the same time, I am confident our bus has a solid system that will serve us well.
As a recap, here are the parts and components I used (links to Amazon are provided where possible – if you purchase from the link, we will earn a small commission):
Circuit Breaker Panels
Blue Sea Systems
- 3-way Switch 8366
- Class T 400 fuse block
- 400 amp JJN fuse
- ST Blade Fuse Block 5026
- 11001 Battery Switch