For the past twelve years, we have been using a 5-foot by 8-foot enclosed trailer when attending rocket launches. It has served us well, but we had started to outgrow it. So, we recently invested in a new 6-foot bv 10-foot trailer built by Diamond Cargo. We researched our options and shopped around before deciding to purchase the trailer from a local dealer.

In addition to being a little wider and longer than our old trailer, the new trailer is taller and has a "v-nose." The interior volume of the new trailer is about twice the volume inside the old trailer.

We've been working on the trailer for several months, but I only recently created this Build. So, while the entries are appearing soon after each other, it really took us a while to complete some of the steps.

When you purchase a new enclosed trailer, it is pretty much an empty box.

The first thing I did was to paint the walls inside the trailer and apply an epoxy coating to the floor.

I replaced the trailer jack with a The Ultimate Trailer Jack. The new jack has a couple of nice features.

First, it has a release pin that quickly drops the jack tube down. This makes it easier and quicker to lower the jack.

Second, it allows you to raise the bottom of the jack higher than you can with the original trailer jack. This gives you a few more inches of clearance when driving over a bump or through a ditch.

The next thing we added was a fold-out RV step to make it easier to use the side door. The step bolts onto the frame below the door, but the bolt holes didn't line up with the frame on our trailer. So, I used an angle grinder to create copious sparks as I cut a piece of steel angle to fit between of parts of the frame. I bolted the steel to the frame and the step to the frame and new piece of steel.

Next, we added a grab-bar handle beside the side door. The RV grab bar that we used folds flat against the trailer when not in use.

Light is important in a trailer like this. Fortunately, LED lights are small, inexpensive, and easy to install. I used two different kinds of lights. I mounted 12V under-cabinet light strips on the roof spars along the length of the trailer. They work well because they provide a cool, bright light that won't blind you. Using many of them provides even lighting throughout the trailer. I also added a couple of brighter LED light bars to the inside front of the trailer.

Even though the cabinet light strips have adhesive tape on them, I used screws to hold them securely in place. I learned with our previous trailer that misaligned lights are very obvious when you turn them on. So, for the ceiling lights in the new trailer, I made a simple jig to align the screw holes along the roof spars.

After drilling all of the holes - a lot of holes! - I screwed the ceiling lights into place. Wiring up the lights was tedious. I thought I would make it easier by attaching quick-splice wire connectors to each of the lights then making up wiring harnesses for each light. I was able to sit comfortably in the house and watch TV while making a dozen wiring harnesses for the lights. So, I did seem to make things easier. But as I started hooking up things in the trailer, I found that many of the harnesses didn't work and I ended up spending a lot of time debugging the wiring. It may have been easier just to splice wire to each light and test them one at a time.

I found some black metallic tape that worked well holding the wires to the roof spars and making it look neat as the tape blended in well.

Lights need switches. So, I added a switch panel inside the side door. I started with a project box and a bank of lighted rocker switches. When I was a kid, I used project boxes for many little electronic gadgets that I made. But I was never very good at cutting holes in the project box lids for switches and meters or whatever. So, the results were often practical but not aesthetically pleasing. This time I had access to better tools. I used a CNC router to cut out a holder for the project box lid. Then I taped the lid into the holder and used the router to cut out openings for the switches and other controls.

We now have eight switches ... and are only using one so far.

The lights needed power. And we would need power for other things, so I built an electrical system into the trailer. Based on the way RVs are powered, the system provides power to 110V as well as 12V devices.

Power is provided by three 100-watt solar panels or an external 110V source. The solar panels charge two 50Ah lithium batteries. The batteries are also charged by a power converter when the trailer is plugged into an external 110V source. The batteries can power an inverter when the trailer is not plugged in. An Automatic Transfer Switch automatically selects the external 110V source when the trailer is plugged in and the inverter when it isn't.

The external power is fed into the Generator Input of the Automatic Transfer Switch rather than the Shore Input to delay switchover to it if a generator is used as the external power source. The inverter doesn't require a delay to come up to speed as a generator does, so it is fed into the Shore Input.