Travel trailer built in generator

If any of you are familiar with travel trailers and fifth wheels you’ll know that they rarely come with a built in generator. The exception is some of the toy haulers with built in fuel tanks for the toys. Here I’ll go over the process I went through to get a generator built in, including remote start (yay!). The built in generator is powerful enough to run the AC unit, can be started remotely and run in any weather, and does not need to be lugged around- a generator powerful enough to run the AC is usually quite heavy. The generator is an older Onan 2.8 Microlite that runs off gas (you can get a propane version). It came installed in my truck camper so I’d been using it for quite a few years. When it was time to sell the old camper it was better to sell the camper and genset separately because the camper was 28 years old and no one would pay that much extra for the genset.

The first question I asked myself when planning this out is why don’t many trailers come with built in generators? I came up with 3 reasons. First, the target market for trailers is quite price sensitive, it’s a lot of money to have one put in. Second is payload issues, many trailers have very little cargo capacity. But I think the most important reason is the fuel tank – the lack of. On a motorhome, the generator uses the main fuel tank (same one as the motor). There’s no fuel tank in a trailer. And there are a LOT of regulations about fuel tanks, for safety and emissions. For example the US EPA requires all built in fuel tanks to have an evaporative emission system – all modern cars have this. I’m pretty sure that’s another big expense. So that brings me to the first thing I had to figure out, and that was a fuel tank. I ended up not putting a permanent tank in at all. Read on to learn what I did… but if you own a small boat with an outboard motor I’ll let you guess.

The next concern to figure out was whether the front compartment was constructed to handle the weight. Nowhere could I find the weight capacity of the storage bin published. So. I had to go with what others are doing in the same trailer. I found out what others with the same trailer are commonly putting in there, and that is 4 – 6-volt golf cart batteries. The most popular is the Trojan T105 battery and it weights 62 pounds, for a total of 248 pounds. I know the generator that I’m planning to put in is 113 pounds plus the two group 24 12V are 38 pounds each, for a total of 189 pounds. Which means I’m putting less weight in than others I know with the same trailer. And just going over the construction of the front storage area, it really looks solid.

On my fifth wheel the place for the generator is up front in the storage bin under the bunk where the batteries are. It has to fit under the landing gear drive, and high enough that the front panel of the generator can be opened. I had to put a raised floor in to support the generator. In the photo below the first support for the raised floor is already installed and is visible on the left next to the framing square. The generator when this is complete will live in a new aluminum box with a door on the front for access and air vents so the engine can breathe. And then there’s the batteries – they cannot be in the same space as a generator for safety reasons. So along with the generator having its own box I’m building a outside vented battery box as part of this project too.