Not having any shore power connection, and a small outboard engine for on demand charging has forced me to be electrically conservative on my boat since I can not just plug in and charge the batteries up whenever I want. The result is that I have upgraded all the lighting to LED lighting, and installed a small but capable solar charging system. This has worked out rather well and I am able to sustain my electrical needs for even week long live aboard trips. The only downside to this is when I need to run small power tools or plug in a 110v device or charger, I have to dig out an extension cord with a shore power adapter and run it. That can often take longer than the project I need the 110v power for.
I decided to install an inverter at the same time I was upgrading the electrical panel. I determined that something in the 400-500w range would probably be enough for my needs, which would mostly be for things like running the dremel or a heat gun to heat shrink electrical connections. I knew I didn’t want the inverter installed visible in the cabin, and I didn’t have any appropriate place to install it even if I did. I had a spot inside a hanging locker that would work great and sit just a few feet below the panel, but that meant I was limited to inverters with remote panels, which means 600w and up. After some research and feedback from other sailors I decided that I would go with the Xantrex ProWatt SW 600 True Sine Wave inverter. I originally looked at the Pro Mariner TruePower 600 Modified Sine Inverter, but found that the remote only has a 10 foot wire, and it is not easily user extendable (read on to see why that is important), and for the small price difference the Xantrex is also a True Sine Wave inverter instead of a modified sine wave.
Having never wired an inverter before, my original plan was to wire the inverter to a dedicated 50A breaker on the panel as outlined below…
But after lots of feedback I changed my plans and decided to install the inverter back closer to the batteries following this general diagram.
My only concern with this design is that I cannot disconnect the inverter from the batteries without disconnecting everything else, and thus leaving some phantom loads all the time. So I decided to add a switch on the positive cable to the inverter. I also decided to add a fuse to the main output since I had overlooked adding one when doing the initial electrical distribution upgrade. The final installation came out like this.
I shortened the main battery cable from the battery switch when I wired it to the new ANL fuse block, which I put a 100A fuse in, then go straight down to the main positive buss bar, and over to the switch for the inverter. All wiring that feeds the inverter is 4AWG. I installed the inverter on a vertical bulkhead about 3 feet from the switch. The inverter is only able to output ~6A @ 110v, so I ran 14AWG 3 strand cable attached to a weather resistant plug and plugged into the inverter…
The mounting location of the switch, while easy to reach and use, makes it difficult to see the LED indicating that it is powered on. The remote switch for the inverter has a 12v input that is used as an “ignition interlock” so that the inverter cannot be powered on without 12v power being sent to that wire first. The intention is that you cannot turn it on unless the engine is running, and therefore preventing your battery from running low. I attached the “interlock” wire to the output of the 12v outlets breaker so that the inverter cannot be turned on without having the 12v outlet breaker turned on, so that if the breakers are all off, the inverter is also off.
Since installing the inverter in the first week I have used to to run a power drill with a wire wheel to clean and prepare the surface for a new zinc, cut out the mounting hole with a Dremel Trio for the new stereo, and charged the battery for my cordless drill.