We are in the middle of a van conversion with LOKI our Ford E250 Econoline extended van. Most van conversions I see on the internet don’t include air conditioners on the roof, but where we live, you either install one, or you just don’t use the van—there’s really no other option. This actually wasn’t our first time installing one of these units, we did it almost 25 years ago, see Installing the AC Units on our MCI Bus Conversion if you’re interested.

The temperatures inside the van, even with 15% (dark) ceramic tint and full reflective sun shades, still reach 120° right now. To bring that temperature down to a sleepable level requires an AC (and probably a generator) with shore power. We considered several options, including trying to use a regular window unit from Home Depot, but it just didn’t work. Those units use less power, around 6,000 BTUs, and cost way less, but venting and installing it properly proved too cumbersome and tricky.

We ended up buying a 15,000 BTU Dometic FreshJet 3 Air Conditioner on sale from Camping World. This should provide more than enough cooling power for our van, but I also wanted to be able to run this AC unit on a small generator and a regular 120v outlet plug. There are two “optional” accessories suggested for the Dometic FreshJet 3, which, in my opinion, should not be optional but included. One of them is the air return, Dometic FreshJet Non-Ducted Mechanical Controls Air Distribution Box (ADB), which makes no sense because you can’t run the AC unit without it, and the second is the Dometic SmartStart 120V Accessory Kit for FreshJet ACs. On a side note, these are available on Amazon, but I wouldn’t recommend getting them on Amazon. There were too many options and too many ways for it to go wrong. The units from Camping World I knew all went together properly.

What it Does

Here’s how they describe this optional item: The Dometic SmartStart AC Accessory reduces AC start-up power demand by as much as 75%. This innovative AC device enables the AC to run on a generator as small as 2,000W, helping to eliminate the need for shore power and making boondocking easy. Specifically developed for Dometic RV air conditioners, it also makes it possible to use an inverter in a solar application without faulting. With the SmartStart AC Accessory, RV owners have the option of moving to a smaller generator, saving weight and money while enjoying quieter AC startups at any time of day or night. SmartStart is pre-wired and comes with everything needed for a quick and easy installation. This lightweight device has gone through rigorous vibration testing to withstand severe road conditions for a comfortable camping season regardless of vehicle size.

SmartStart Features

• Reduces AC start-up power demand by as much as 75%
• Enables the AC to run on a generator as small as 2,000W
• Makes it possible to use an inverter in a solar application without faulting
• Engineered exclusively for the Dometic FreshJet Air Conditioner
• Pre-wired and comes with everything needed for a quick and easy installation

These points convinced me to spend another $300 on a box which, now that I have installed and tested it, feels like it should be included with every Dometic AC unit. The last point, about quick and easy installation, I’m not so sure about—it wasn’t exactly straightforward.

SmartStart Manuals

The manual is nowhere to be found on any Google search, Camping World’s website, or Dometic’s website, so I’ve linked to it here in case someone can’t find it. I actually have been unsuccessful in finding just the link, so here is the full blown PDF that came with the SmartStart and here is the manual you actually need, the installation manual for the SmartStart 120v Accessory Kit. If you are actually looking for the manual for the Dometic FreshJet 3 that’s here.

The only way I was able to access the PDF was through the QR code included with the paperwork for the SmartStart kit, so you can probably scan that from the first PDF above. That said, the manual is written as if they assume everyone is an electrical engineer. I am not. But I can read and follow directions, and even though I followed them to the letter, I still got confused several times. So I’m making my own instructions here, written in more plain English.

Keep in mind, I’m doing this for the installation of the Dometic FreshJet 3 AC unit. It’s slightly different for each unit, so you will need to read the manual specifically for the unit you are working with at the time.

Installing the SmartStart Kit

Please read the installation manual in full and follow it exactly. I’m going to put a few points below that I learned from doing this:

1. You don’t have to be an electrical engineer to do this installation, but you do have to be very diligent and slow. Everything inside there seems very fragile and easy to break.
2. The manual never told me to disconnect or not to disconnect the capacitor wires but just to add the new ones. You are not supposed to disconnect the existing ones.
3. You are basically replacing the existing wiring harness with a new wiring harness and bypassing the original wires, but leave them in the channels. Do not remove them for various reasons; if you later remove the SmartStart kit, you won’t have a way to run the AC.
4. Be very careful when you are disconnecting and reconnecting wires. If you break off any of the prongs, you will need some skills to repair it or you will have a really bad day.
5. Be careful when removing the putty from the wiring harness and keep it clean to use when you replace everything.
6. Be sure to test the installation when you are done. This is not going to be all that easy (see below).
7. Get some help if you can. I did this by myself until I was ready to test it, but additional eyes would be very useful.
8. Wiring in the channels is very tight, be very diligent with how you lay wires across the channels
9. They give you “just enough” wiring to make it from the SmartStart to out of the capacitor for the ADB on the roof, make sure you leave enough wire for the ADB.
10. Use extra zip ties so you don’t bend copper or have loose wires

Some Review Thoughts

I did not anticipate this to be as involved as it was from the sales photos. This is a complete replacement (bypass) of the existing wiring system on the Dometic Air Conditioner, and you will need at least an hour or two. I saw two wiring harness ends and thought, “Oh, 5 minutes, plug in two ends and I’m done.” Not so.

Make sure you test this when you are done. I was not going to do this since there is no good way to plug this into your home wall outlet, but I’m glad I did because I had wired something wrong. In my particular installation, I had disconnected the original wires going into the capacitor, and when we started up the unit, it only blew on high with no cold. I took it apart, put those wires back on the capacitor, re-tested it, and it worked perfectly.

How I tested my installation was by putting the Dometic FreshJet 3 on two sawhorses, connecting the wiring harness to the Dometic FreshJet Non-Ducted Mechanical Controls Air Distribution Box (ADB) that I bought with the unit. Then, I took a sacrificial extension cord, cut the end off, and wired it directly to the ADB so I could plug it directly into my wall outlet. I’m sure this isn’t the perfect way to test this, but it was my way, and it worked fine.

My unit arrived with various pieces of plastic broken, and I had to figure out if they were vital or what purpose they served. This is a review of the SmartStart, not the Dometic FreshJet 3, but the cap to our compressor arrived broken. That was irritating but not enough to return it. There were other non-essential broken pieces of plastic, also equally irritating but not enough to return it.

All said after the installation was completed. I’m assuming it does what it says it’s supposed to do. I’m not an electrician with a multimeter, and I didn’t check the voltage startup, but I probably will before we actually put it on the roof of the van. It did run smoothly, and there are two LEDs at the top of the SmartStart box that tells you if it has power and if it has a “fault” going on. Of course you can’t see those unless you take the shroud off the AC unit, but they were lit up when we ran our test.

Dometic says this is “quick and easy” and I would argue that is not the case, but it is doable by any reasonably educated individual. I wish the manuals were easier to find, and written in a way that a normal human can understand them, but they only left out one detail about the capacitor. The price seems very steep at $300 when you have just paid over $1,000 for the AC unit itself, so that was irritating, but I do want to be able to run this on a smaller generator or even possibly solar power down the road.

One quick note. The installation process on the Dometic FreshJet 3 unit seemed to be the easiest of all the units the SmartStart works with, so your complexity of installation may vary with other units.

Installation Photos