The Battery Monitor and Inverter Are In!!!

I cannot believe I have successfully brought this battery bank upgrade project to term. Thank you so much to everyone who provided advice along the way. I also have to thank Xantrex for it’s very expensive for what you get but priceless battery monitor connection kit, without which I really don’t think I could have done the battery monitor installation.

All projects involve compromise, and this one was no exception. I don’t like where the battery monitor and inverter are located, but I’m thrilled with where the 120V connection from the inverter ends up.

The first part of today involved removing all the battery connections and pulling the batteries out of the compartment. They are heavy suckers! While I got the fuse and shunt screwed to the side wall, my mother went into her shop and cut a new floor for the compartment since the plywood I had installed had gotten warped and sloppy looking.

I used to have the batteries sitting perpendicular to the rig. Now, they are parallel.

This is the shunt screwed into the side wall of the compartment. All my negative connections (save the inverter, not yet hooked up) tie into it. The fuse is about two feet to the left, with the positive connections installed the same way.

As I continued to work, she tried to trace a path from the battery compartment to the study for the inverter starter and the battery monitor wiring. Well, there was no path for the wires. We encountered obstacle after obstacle. We could have brought the monitor up on the driver’s side, but there was only enough starter wire for a straight run, so the effort didnt feel worthwhile.

My idea of putting the inverter into the same compartment as the batteries in its own mini-compartment also didn’t work because my cables for it were just a wee bit short. That meant the inverter had to go up into the living room. If we were going to make a hole in the floor for that, I was going to simplify the project and bring the battery monitor cable up through there, too.

As for the inverter remote starter, I thought I wasn’t going to need it where it is, but it will be installed when my mother and I finish up the woodworking projects. A picture below will explain why.

Hole in the floor allowing the passage of the 12V, battery monitor, and 120V cables. It’s finished with a computer cable conduit like you see on desks. We’ll also be adding insulting material.

My mother then took off to buy some exterior-grade 120V cabling while I got everything but my inverter hooked up in the battery compartment since I wasn’t too sure about the ground issue. When she came back, it was time to pass the 120V (15A) cabling from the inverter in the passenger side of the living room at the front of the rig to the shore power cable compartment located just past amidships on the driver’s side at the rear.

I was actually up a good part of the night thinking about this wiring issue. I had originally thought that the inverter would be in the battery compartment. So the easiest thing would have been to install an exterior-grade outlet in the compartment wall, snake the shore power cord under the rig, and plug it into that outlet.

Then I thought about that. I just didn’t see myself plugging and unplugging several times a day when I am traveling. Having the outlet in the shore power cable compartment would mean being able to leave the shore power cord plugged into the inverter all the time. I would then just have to turn the inverter on and off as needed.

We brought the 120V cabling down into the battery compartment through the same hole as the 12V cabling and out an existing hole in the side of the compartment. Now, we just had to get it across and down the rig and up into a compartment full of electrical wiring. Well, crawling under the rig notwithstanding, this was the easiest part of the day!

We got a couple of false starts because of the dang muffler that prevented us from crossing the rig sideways. A neighbour who is knowledgeable about cars was out in his yard, so my mother went to ask him for advice. He said that there would be a bridge of sorts at the very front of the rig because of the transmission and that would give us a path far enough away from the muffler.

He was right! And soon as we got the cabling to the driver’s side, we were able to follow the generator wiring’s route all the way to the back of the rig. The hole for that wiring into the compartment was big enough for us to fit the 120V cabling through after removing the insulating material! We still need to fit a male fitting at the inverter end and a female fitting at the compartment end, but the hard part of that job is done.


The 120V exterior-grade cabling is essentially a heavy-duty extension cord that will live, curled up, in the shore power cord compartment.

I will be putting a female end on this cable. This will allow me to add the 30A to 15A adapter into which I will plug the shore power cable. Don’t worry about the wire end being open since it’s not connected to anything.

Once all the cabling was run outside, it was time to get the battery monitor cable run inside and hooked up to the monitor. After much debate and hemming and hawing, I concluded that the easiest place to install the monitor and still have it be readily visible was behind the ladder to the loft.

The cabling cuts across the roof of the cab (floor of the loft).

I made all my connections as per the Xantrex diagram. While I was outside doing the fuse hookups, my mother secured the monitor in its hole in the wall. How that works is the monitor is threaded like a bolt and there is a plastic nut to hold the monitor in place behind the wall. I’m just glad I remembered to thread the cabling through the nut, then the wall, before doing all the connections!

It works!

Can you believe this display was actually bright orange?!

As for the inverter, Croft determined that the ground is to protect me from the inverter casing in the case of a bad situation with the 120V side of things. This fairly confirmed what my research told me. So I was able to hook up the inverter to the battery bank and test it, but I will be adding that neutral wire next week (I won’t be using the inverter in the meantime, but it let me put away my tools and repack the compartment).

The inverter is on the floor in the living room behind my big arm chair. I’ll have to be extra diligent in sweeping behind there to keep the dust and cat fur out of it!

The inverter works (pardon the wonky angle of the photo)!

Right now the voltage reading right at the batteries, on the solar monitor, on the inverter, and on the battery monitor all reads the same, 13.3V (remember, I’m plugged into shore power). It will be interesting to see what sort of voltage drops I’ll experience, if any, once I start boondocking. I expect the drops to be minimal since I have very short cable runs with very small gauge cabling. I spared no expense for this project!

I feel so satisfied and competent today. This is the first time I’ve ever done a project with my mother where she was there for labour and I was there for the technical portion.

Now, to see how the rig reacts when I plug it into the inverter. I hope that is not exciting. 🙂

Blog Widget by LinkWithinShare on Facebook
If you enjoyed this post, make sure you subscribe to my RSS feed!


  • Nice!!!

  • Hopefully that comment will still hold when I’m off shore power and test running the new system. 😀

  • Hi Rae,

    Wow! Totally technical & waay too technical for my little pea (or pee?) brain to figure out. Once on the road I’m sure it will make more sense. But still, what an awesome job.

    Great details too 🙂 .

    *pats Rae on back*


  • I have four years of experience living in an RV helping me get this stuff. You’ll get it one day, too!

  • I trust you topped the water off in the batteries…

  • You are woman, hear you roar.

  • Croft, nope. They weren’t due for water.

    Bast, love you!

  • Hi Rae:

    Are the cables long enough to allow you to bolt the inverter to the side wall? Or to the back of the cabinet that you have (had?) right by the entrance door?

    The fan in the inverter will pick up a lot of dust and cat hair, anything that you can do to get the inverter off the floor would help.

    I like your detailed explanations, I am going to start referring DIY RV owners to your blog.

    How about putting some tape on those 120V breakers that need to be switched off before you connect to the whole house inverter? That way you can find the right breakers even in the dark.


  • Good idea about marking the breakers Carl. I was going to suggest a dab of white paint on the ones you turn off. And yes, the dust and hair could be a problem on the floor.

  • The cables for the inverter are only 3′ long. There is absolutely nowhere else for it to go. I know that dust and pet hair are going to be a constant battle with it. When not using it, I am going to put a cover over it.

    Good idea about marking the breakers!

  • I looked at the pictures again and have a better idea where you have the inverter. I am guessing that you do not want it in the notch bolted to the outside? yellow wall, understood.

    I would be willing to help you get your generator started if you still have it. I finished all your blogs last night and did not see any more mention of it. Even if you do not want to keep the generator it has a lot more reasale value if it is running.

    BTW your roof AC will only work with a built in generator not one of the small (and quiet) 1000W inverter generators.

    My simplistic rule of thumb is, if you can carry the generator then it is not big enough to power an air conditioner (unless you are a weight lifter LOL).

    You have my e-mail address if you want to work through the starting process.


Got anything to say? Go ahead and leave a comment!