This blog post is the 4th in our RV Electrical Upgrade series. In it, we'll be installing the Progressive Industries EMS-HW30C and finally wiring up both the AC and DC sides of our RV.
Series: RV Electrical Upgrade
If you haven't already done so, make sure to check out the earlier posts in the series where we lay out our goals, install 3x 100Ah Battle Born Lithium batteries, a 3,000W Victron MultiPlus hybrid inverter / charger and several other items, and hook-up a high speed DC-DC charging system for charging our batteries from our truck when towing.
In this article...
- Progressive Industries EMS-HW30C
- Connecting the 120V AC circuits to the RV
- Connecting the 12V DC circuits to the RV
If you've been following along, you'll know that although we've installed all the major components, we haven't connected them to the RV's electrical systems yet. That's what we'll be doing in this blog post. We'll be taking the opportunity to install the surge protector too.
Progressive Industries EMS-HW30C
First, what on earth is it?
At its simplest, it is a surge and electrical protector that can help to protect your RV from power surges, incorrectly wired shore power circuitry, and other similar electrical risks.
As RVers, we connect our rigs up to power at lots of different locations - and we don't always know how well they are wired up. And even then, things can go wrong - surges from lightning strikes, brown-outs at RV parks overwhelmed by too many people running their AC, and so on.
The idea of a device such as this is that it attempts to protect your RV's electrical systems from those problems. There are 3 ways it does this:
- When you first connect shore power, before the device allows your RV to use that power, it runs a series of checks to make sure everything is fine, and only then turns on the power.
- It continually runs checks on the shore power to make sure (pun intended!) that everything is looking healthy, and if not, it kills the power.
- As a last resort, if something catastrophic happens (e.g. a major power surge) that the device cannot stop, it should sacrifice itself to save your RV. It's a lot cheaper and easier to replace that one device than all the wiring and appliances in your RV!
The Progressive Industries website has full specs on the device if you're interested in learning more, but the bottom line is this: it's like insurance for your RV against something going wrong with the shore power.
Let's tackle that oh-so-catchy product name, the EMS-HW30C.
EMS stands for Electrical Management System - it's a fancy way of saying what I described above.
HW means it's hardwired. You can also get a portable version of this product, the EMS-PT30X. That doesn't require installation, it just connects directly to the pedestal. But bear in mind, these devices aren't cheap, so it's more vulnerable to going walkabouts!
30 means it's the 30A version. If you have a 50A rig then you'll be wanting the EMS-HW50C. Simple!
As for the C at the end, I have no idea.
There are other companies out there that sell similar devices, but our research led us to Progressive Industries as their products were well reviewed online. We wanted it hardwired because we're not afraid of the installation and I'd rather it doesn't get stolen!
I hope that gives you a good overview of what this device is and why we chose to install it. Speaking of which, let's move onto the install.
Connecting the 120V AC circuits to the RV
It doesn't really matter whether you connect up the AC circuits or DC circuits first, so we started with the AC ones.
At the moment, the Victron MultiPlus is totally isolated from the RV's wiring. Time to change that.
Right now, shore power comes into the RV and goes to the AC distribution panel. So when you have shore power, all your AC outlets and appliances work. One of these items is the onboard 12V charger that charges the existing batteries.
We want to modify this. We want the shore power to first of all go to the EMS-HW30C - this makes it the front line of defense in our RV. Nothing gets in without going through it.
From here, rather than going to the AC panel, the power needs to go to the Victron MultiPlus. Although it may sound counterintuitive sending AC power into an inverter, remember it's a hybrid inverter / charger. This means that it needs AC power to charge the batteries, but the MultiPlus can also boost the incoming shore power by inverting power from the batteries if necessary.
Finally, we need to connect the output side of the MultiPlus back to the AC distribution panel.
Installing the Progressive Industries EMS-HW30C
The first question is: where do we want to install it?
Ideally you want it close to the AC panel, in a place where the shore power wires pass through. There's not a lot of space around there, but we have a cunning trick!
If you've been following closely, you'll realize we no longer have a need for the onboard charger, since the Victron MultiPlus will now be fulfilling that role.
The charger is situated immediately underneath the AC panel. Perfect!
Warning: If you are not completely confident in your ability to work safely with electrical wiring, stop now and find a professional.
Before we go any further, turn off AND UNPLUG the power. Yup, all of it. We disconnected the shore power cable and moved it well away from the pedestal. We also turned off all our switches under the bed, and disconnected the 12V battery on the tongue - do it now and then it's done.
I removed the cover on the front of the AC panel, and double checked the power was off using a digital multimeter - better safe than sorry!
Some of the wires are pretty thick, and it can be a little hard to follow, but we took our time and carefully removed the charger from the bottom compartment. This leaves a space just big enough for the EMS. Oh, that reminds me, that thing is way bigger than I thought it was going to be (9-1/2" x 5" x 3"), so make sure it will fit wherever you're planning for it to go.
I won't needlessly repeat everything that's in the instructions for the EMS, but you'll want to disconnect the shore power wires from the AC panel and feed them into the input side of the EMS, following the instructions carefully. We trimmed the wire a little so it would fit - take your time!
We were able to drill some small holes to secure it in place with screws - but don't screw it in just yet. We need to connect the output side.
Wiring the MultiPlus to 120V AC
This is where things get exciting, and a little bit challenging! We need to run a wire from the EMS to the MultiPlus (input side), then from the MultiPlus (output side) back to the AC panel, just above the EMS.
How you install this will really depend on the layout of your RV and where the AC panel is in relation to the MultiPlus.
For us, we had to run our wires from the inverter, down to the front bay, then through the underbelly, along the frame rail, and cut a hole up into the floor of the trailer near the AC panel.
We bought a 50ft spool of 10/2 wire from Lowes, and some split loom that would fit the wire. The thick, solid-core wire is really stiff, but we took our time and carefully threaded both wires through. Having two people helped, but it still took us a couple hours crawling around under the trailer in the humid August heat of Texas to make the relatively short run.
The key is to make sure the cable is secure and protected. We used plenty of split loom, rounded or taped up any sharp edges, and zip tied everything to make sure nothing would rub - that would be bad!
I'm not going to go into the specifics of exactly how to connect the wires into the EMS, MultiPlus and AC panel - we read the manuals carefully and followed the instructions! It's easy, but important to get right…obviously!
The last thing to wire up is the display for the EMS. It has a small data cable that allows you to mount the display up to 14ft from the EMS itself. We chose to mount it nearby, just below the AC panel - a small hole for the wire and some Command Strips is all it took!
Adventurous Tip: The display for the EMS shows various shore power voltage, current, errors, etc so you want it somewhere you can see it. But, the red display is bright and it can't be turned off, so don't mount it somewhere that's going to be annoying at night!
Once we were done, we tested the system by reconnecting shore power, and turning on the various switches and breakers you turned off. Oh, and we switched on the MultiPlus too!
After testing, we turned everything off and screwed the EMS into its final position, making sure all the wires were secure and tidy.
At this point in the install, we had shore power going into the EMS, then to the MultiPlus, and finally back to the AC panel. This is a good stopping point if you need it - we used it to run the Air Conditioning for a while to cool the RV back down.
Adventurous Tip: Although the AC circuits are hooked up, the 12V battery on the tongue should still be disconnected so no 12V appliances (lights, etc) will work just yet.
Connecting the 12V DC circuits to the RV
We're onto the home stretch now…wiring the Battle Born Lithium batteries into the 12V circuits on the RV.
Although the original 12V battery was on the tongue and our Lithium batteries are under the bed, they're actually not that far apart. Our batteries had 2 connections - one to the front electrical bay where it connects to the rest of the RV's 12V wiring, and one directly to the tongue jack. That made sense when the battery was right next to the tongue jack, but not any more.
Connecting 12V Battle Born Lithium batteries
The first step was to remove the old 12V battery and battery box. With the wires disconnected, it was easy to remove the straps and take the entire battery box out. It's only when you do that you realize how INCREDIBLY heavy lead acid batteries are. Wow!
We were staying at Rainbow's End in Livingston, TX while doing this install. At the social event that week, we shared that we had a nearly-new 12V battery and OEM converter available to a good home. We were delighted to be able to give them to a lady living in a Dodge van that she's renovating. Always good to see these things go to a good home.
Anyway, wiring our new Battle Born batteries into the RV is simple enough. We connected a ground wire back in Part 2 when we first installed the batteries, so all that's left is to hookup the positive side. Reusing the wiring run we created before from the positive bus bar under the bed to the front electrical bay, we ran some 6 AWG wire, again wrapping it in split loom to protect it. A ring connector crimped onto the end secures it to the terminal in the front electrical where the old battery had been connected.
Powering the Tongue Jack
It's always easier to reuse existing wiring if possible, so rather than removing the old 12V battery positive wire, I spliced this into the tongue jack wire. The tongue jack wire had an inline fuse so I kept this, but otherwise it's now connected into the 12V system along with everything else.
One thing to note about this is that it means the jack will lose power when the main battery disconnect switch is shut off. Because it was directly wired to the batteries before, it was always powered.
Personally, I prefer having it this way around. When I disconnect my batteries, I know that everything is disconnected, not everything-but-the-tongue-jack. Also, for additional security, it means nobody can operate the tongue jack if we disconnect the batteries when, for example, we store it - unless they use the manual override, obviously. I know some people remove the fuse from the tongue jack to achieve a similar goal.
There was already a battery disconnect switch in our front storage bay - this is actually where the 12V wires going from the front electrical bay disappear to. We decided to leave it there (it's not doing any harm) so we could in theory use that to switch off everything except the tongue jack.
Testing the DC
With all the DC wiring connected, it's testing time again. Ensuring that all switches and breakers are were off, we started nearest the battery and gradually turned them on, one by one. Everything worked first time, no issues to report!
And that's it. 300Ah of Battle Born Lithium batteries, connected to a Victron 3,000W MultiPlus hybrid inverter / charger, powering our entire trailer.
After we had everything working, we pushed the system hard - running DC appliances as well as the inverter. Then, with high load in the system, I used an IR temperature gun to take temperature readings under the bed - paying particular attention to the wires and terminals.
In the course of doing so, I noticed that the positive cable going to the inverter was noticeably warm. It turned out to be a loose terminal connection of the positive bus bar - an easy fix. Once we corrected that, everything looked fine - all temperatures were barely above ambient.
One of the advantages of the Battle Born Lithium batteries is that they are zero-maintenance. While that's true, the same isn't true for your electrical system overall - although the maintenance is minimal.
But checking all connections are secure is something you should do regularly. I'd suggest doing this after your first drive with the RV after the installation to make sure nothing has come loose. I also regularly visually inspect all components to make sure wires aren't rubbing, there's no sign of damage, and that everything is secure. So far, no problems! I think using high quality components and taking our time with the install has contributed to that.
We installed all of this back in August 2018, and it's now May 2019 - a full 9 months later. We couldn't be happier with how it all turned out. Although we've added a few things since (e.g. solar, more monitoring, etc), the EMS-inverter-battery setup is unchanged. And everything is working great!
Originally I had intended to continue this series of blog posts to include all the other electrical items we've done, but I'm going to break those out separately. So if you haven't already done so, make sure to subscribe to follow our journey as we add solar to the RV, install a couple of DC fuse panels to clean up wiring under the bed and behind the TV, add some advanced monitoring and much more!
If you've been reading through this thinking: "I want a system like that but don't feel comfortable installing it myself", then don't despair - drop us an email and I'm happy to answer questions, and refer you to some installers we know personally who may be able to help you.
Let us know in the comments if you've found this blog series interesting, and we'd love to hear what you've installed or are considering installing.
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