My Experience with Retrofitting Parking Air Conditioners for Slide-in Campers After 4 Modifications

Tags: Slide-in Camper, Camper Air Conditioner, Camper Modification, Parking Air Conditioner

Based on the experience summarized by many slide-in camper owners, people usually travel with slide-in campers more often in spring and autumn. In winter and summer, most choose southern routes in winter and northern or mid-western routes in summer. The air conditioner for slide-in campers is also a common issue, and installing a suitable air conditioner for self-modified slide-in campers has long been a hot topic in the slide-in camper modification community. With my experience in retrofitting slide-in campers, I will reveal some facts about slide-in camper air conditioners for you.

My first modification was at the end of 2006. Back then, I had little idea about slide-in camper equipment, so I bought a 1HP household air conditioner. I didn’t know about inverter models at that time; I only thought a 1HP air conditioner could theoretically cover 12 square meters and would be absolutely sufficient, so I installed it. The power supply was a UPS connected with 8 12V 60Ah batteries in series. The air conditioner was non-inverter and only 1HP, so the UPS alarmed and shut down after less than two hours of use in the car. After inspection, there was no equipment failure—only high power consumption.

Then I thought a dedicated slide-in camper air conditioner would definitely solve this problem. Since I had just installed a new air conditioner and couldn’t remove it, I carried a generator to power the air conditioner for nearly two years. It should be noted that household air conditioners can be used in vehicles as long as there is power.

For my second modification in 2008, influenced by the idea that dedicated slide-in camper air conditioners had many advantages, I visited various exhibitions to learn about them, with little gain. However, they looked quite premium (all-in-one with sleek lines). I then ordered one, but its cooling performance was average—rated at 3800W cooling capacity, worse than my original 1HP unit. It was noisy and consumed a lot of power.

In 2011, learning from previous lessons, I decided to buy a genuine 1.5HP Gree air conditioner. After purchasing the air conditioner, I needed a power supply, so I bought a 3000W sine wave inverter, a high-frequency model, which cut off power after a short use. As far as I know, high-frequency inverters have relatively low power consumption but are unstable when driving high-power air conditioners. Low-frequency inverters have relatively higher power consumption (nearly 10A) but are more stable; I heard there are now low-frequency inverters with power consumption below 3A.

For my fourth modification in 2015, I kept the same air conditioner, which had been in use for over three years while driving. This proves that household air conditioners work fine when the vehicle is moving.

Now let’s talk about how the air conditioner works when parking.

The key issue is the power supply: mains electricity, solar power, generators, or backup batteries. One reminder: many self-modified vehicles only have front air conditioners without rear ones. Even for short-wheelbase vehicles, the rear gets no cool air at all in summer.

Let’s discuss solar power, generators, and batteries. Solar power is great if it’s high-power with a small area, and its price is affordable for many now; it’s also green energy. Although solar power requires upfront investment for free later use, it has many limitations—it must be parked in sunlight, and it doesn’t work in shade or on cloudy days. Besides, the full rated power of rooftop solar panels is rarely achieved. So solar panels can be installed, but they only supplement battery power under normal conditions.

Generators should be backup equipment. As long as they function properly, they work reliably, but there are several problems: apart from noise, they vibrate a lot when installed in the car and are unsafe if placed outside. Worse, starting the generator can be tricky—most gasoline generators use carburetors instead of electronic fuel injection. If a generator hasn’t been used for a while, it’s hard to start and requires carburetor cleaning. This happens frequently with domestic generators, and imported ones are no exception. So if you plan to buy a generator, learn to clean carburetors first.

Now for batteries. Most batteries on the market are ordinary lead-acid, gel, spiral-wound, and lithium batteries (ternary or lithium iron phosphate). Lead-acid batteries are the cheapest, followed by the others in order, with lithium batteries being the most expensive. A branded 100Ah lead-acid battery costs about 400–500 yuan, while a lithium iron phosphate battery costs around 2000 yuan. Most slide-in camper enthusiasts install batteries above 300Ah. In terms of weight and volume, the first three types are twice that of lithium batteries. Lithium batteries have become popular in recent years; opinions on their safety vary online, but the price is manageable for most slide-in camper owners.

I have been researching lithium battery manufacturers, learning from users and tracking their experience, which has been positive. So I plan to buy one too. A 400Ah lithium battery has a theoretical capacity of 4.8kWh, slightly less in practice, but sufficient for night use.

When installing an inverter air conditioner in a vehicle, optimize its usage. An undersized unit may consume more power than a non-inverter model. Although inverter air conditioners start at low power and ramp up, a small unit will run at full speed, with power exceeding the rated rating (check the label: usually 80W to over 1000W). If the air conditioner is undersized, it will run continuously and fail to maintain a constant temperature at low speed. From my experience, when using an inverter air conditioner, first run the vehicle’s air conditioner for 5 minutes to cool the interior to 27–29°C, then switch on the inverter air conditioner set to 26–27°C. At this point, the air conditioner consumes 400W–500W. There are now low-frequency inverters with no-load consumption below 3A, making the total power consumption 40Ah per hour.

With a 300Ah battery, it can run for 5–6 hours or longer at 70% discharge (lower power consumption at night). Larger battery capacity means longer parking time. Household inverter air conditioners are widely used and reliable; batteries are easy to buy, and an inverter is a must. So I think conventional equipment is more practical.

Inside the camper is a constant home, outside are ever-changing scenery. Traveling with family or friends in a slide-in camper is everyone’s dream. In regions with distinct four seasons in China, temperatures change rapidly, making the slide-in camper air conditioner particularly important. When modifying a slide-in camper, expand the space and reduce weight appropriately—every accessory should be fully functional. Solving this problem will benefit many slide-in camper owners.