In case anybody needs proof that I love my wife, I’ll tell you about the Inverter we installed in the Airstream. You see, my wife loves her Blendtec Blender, which checks in at 1800 watts of pure blending bliss. She found a lower-wattage hair dryer for use in the Airstream, but that Blender was going to come along with us. Prior to this upgrade, every boondock blend required hooking up the Honda 2000 generator. Since my prime motivation for this entire power upgrad was laziness, I wanted to make sure that blending was easy.
Two types of inverters exist in this world: Pure-sine wave and Modified-sine wave. The Pure-sine wave inverters produce an AC power signal that looks very much like we are used to in home wiring. Modified-sine wave generators produce an AC power signal that is ‘blocky’ and follows the desired signal with some approximation. Some electronics do just fine with a modified-sine inverter, and they are MUCH cheaper. Many advanced electronics don’t do well with the blocky signal approximation and so require the more expensive variety. I decided to buy quality in this case, and chose a pure-sine inverter.
All pure-sine inverters are expensive, but some are much more so than others. The inverter I chose was the Samlex Solar PST-2000-12 PST, which I actually purchased at BestInverter.com due to a slightly overall cheaper price. I also purchased the RC-200 Remote Control Panel for mounting out in the kitchen.
The product listing pictures of this inverter make it look quite small. Really, it is pretty darn huge. I had used measurements before purchasing to verify that I would be able to fit this where I wanted, and it fit rather well. I mounted the inverter under Cara’s bed, with the DC power connections on the side closest to the DC wiring panel. With the high amperage draws required to produce 1800 watts of AC power, the voltage drops over distance. We minimized that voltage drop by using large wire (AWS 2/0), and by keeping the run as short as possible. The design of this inverter means that the AC power cable actually comes out of the other end, but the length of the AC wire is much less of a problem than the length of the DC wire.
Here, for some scale, is my completed DC wire panel with most of the blue inverter visible. (Look down below for a picture with some protective panels in place.)
When I added the inverter, I also added two additional components to my DC wiring setup. I added a 250 AMP fuse to prevent the inverter (or anything else, really) from drawing too much power through the wires. I also added a disconnect switch that could isolate the inverter from the rest of our Airstream’s DC wiring. Both of these components were wired into the positive wire leading to the Inverter.
I mentioned this on my last post about the battery upgrade, but it is worth mentioning again. The 2/0 wire that I used is very large, very stiff wire. It is nearly impossible to bend short sections of the wire to fit between the necessary mounting screws after the lugs have been crimped on. Before I crimped the ends, I made sure the wire was the needed length and bent if necessary to align as nicely as possible. I then marked the cable with a sharpie to help me align the lugs at the proper angle to make the connection. Short sections of this wire DO NOT TWIST. By being careful and triple checking my alignment and configuration, I was able to make every wire segment work properly without stressing the wire. As with nearly everything in RV life, you will have more success if you are not in a hurry.
After adding the DC wire connections, I ran the remote control panel wire from the end of the inverter down to the kitchen, where I cut an appropriately sized hole underneath the Solar Charge Controller remote panel. The length of my run was just slightly longer than the remote control wired provided by Samlex, so I added a length of wire here. It is worth knowing that the cable provided is a cross-over RJ50 10p10C cable (not a straight cable). You will need to either replace the entire length of the wire with a cross-over cable, or use a 10p10C adapter to join it to the needed length of straight cable. If you don’t understand this, ask me or call Samlex and explain your situation. 10p10C cables and adapters are not very common, so you will likely need to order this online.
Having a remote control for the Inverter was a must for us. The inverter itself has a switch on it, but the inverter is mounted right under a sleeping kid. I did NOT want to disturb anybody just to turn the inverter on. The inverter itself does beep when turned on, but the noise isn’t super loud and it never wakes my kids up. Mounting the remote panels for the inverter and the solar charge controller also makes load monitoring easier. The solar charge controller is connected to a shunt battery monitor, which allows me to compare AC load with DC load and battery voltage. I highly recommend getting remote panels and mounting them someplace convenient.
The last wire to add was the AC wire running from the inverter to my AC panel in the kitchen. (I actually ran this at the same time as the control wire above.) This was a simple task, though the process of wiring it into the Airstream’s AC system was complicated enough that I’m going to write about that in a dedicated post.
Installing the DC wiring was tough, but a good thing to get finished in my project. The wires themselves are hidden behind a panel that I modified to fit the inverter. I also added some wood that covers the top of the main DC fuse to prevent things from dropping on it.
And here we are, with the DC power stuff complete and only the AC wiring left to complete.