When considering an off-grid lifestyle for your RV, understanding how to power your air conditioner using a battery setup is crucial. This guide aims to demystify the process, explaining the components needed and how they work together to keep your RV cool without relying on shore power. (Watch the 18 min video below)
Understanding the Basics
Why Go Off-Grid? Going off-grid with your RV means independence from traditional power sources, giving you the freedom to travel and camp in remote locations. However, the cost and complexity of setting up a solar power system can be daunting. A significant part of this setup often includes the desire to run the air conditioner, which requires careful planning and investment.
Air Conditioner Power Requirements Most RV air conditioners, like the Dometic Brisk Air 2 model, are connected to a 20-amp breaker at 120 volts. The challenge is to understand how much power they consume and how this translates to battery requirements. A typical air conditioner can draw around 14 amps at 120 volts, which equates to roughly 1,700 watts.
Components of an Off-Grid Power System
Inverter The inverter is a critical component that converts the DC power from your batteries to AC power required by most RV appliances. For our example, we use a Victron 3000 watt inverter, capable of handling the power needs of the air conditioner and other small appliances simultaneously.
Battery Lithium batteries are preferred over lead-acid batteries for their higher efficiency and ability to handle larger loads. For instance, a Big Beard 280 amp-hour lithium battery can significantly outperform a standard 100 amp-hour lead-acid battery.
Soft Start A soft start device is essential for reducing the initial power surge when the air conditioner starts. This device helps manage the inrush current, protecting your system and allowing it to run more efficiently.
Running the Air Conditioner on Battery Power
Setup and Test To test the setup, we connect the air conditioner to a single Big Beard battery via the inverter. The battery needs to handle the air conditioner's start-up and continuous running load, which can peak at around 200 amps from the battery.
Performance In a controlled environment at 75 degrees, the air conditioner, along with a small additional load, runs smoothly for about an hour and a half on one battery. This test demonstrates the capability of a high-quality lithium battery to handle significant loads efficiently.
How Many Batteries Do You Need?
Calculating Battery Requirements To determine how many batteries you need, consider the continuous power draw of your air conditioner and other appliances. One Big Beard battery can power the air conditioner for about an hour and a half. Therefore, if you want to run the air conditioner for longer periods, you will need multiple batteries:
- Two batteries for roughly three hours of run time.
- Four batteries for about six hours of run time.
Nighttime Considerations Since you can't rely on solar power at night, ensure you have enough battery capacity to last through the night, typically requiring more batteries than for daytime use alone.
Solar Panels: Maximizing Daytime Power
Solar Panel Requirements Solar panels charge your batteries during the day, offsetting the power used by the air conditioner. To run a 1,400-watt air conditioner continuously during daylight, you need at least 1,400 watts of solar panels. However, it’s advisable to install more to account for inefficiencies and to extend your usable power window.
Roof Space Limitations The number of solar panelsyou can install depends on the available roof space of your RV. Modern RVs typically have room for several panels, but maximizing this space ensures you get the most power possible. Aim to fill your roof with high-efficiency panels to make the most of your investment.
Practical Tips for Managing Off-Grid Power
Monitor Your System Utilize monitoring tools to keep track of your power consumption and battery status. Many lithium batteries, like the Big Beard battery, come with Bluetooth capabilities for real-time monitoring.
Energy Conservation Be mindful of your energy use. Running multiple high-draw appliances simultaneously can quickly deplete your battery. Prioritize essential appliances and manage usage to extend battery life.
Regular Maintenance Maintain your solar panels and batteries to ensure optimal performance. Clean your solar panels regularly to avoid dust buildup that can reduce efficiency, and periodically check your batteries and connections for any signs of wear or damage.
Plan for Expansion As your needs grow, plan to expand your system. Start with a basic setup and add more batteries and panels as needed. This modular approach allows you to spread the investment over time and adapt to your energy needs.
1 comment
I am a “newbie”… by myself and am learning so much about in the in’s and out’s of every aspect of “RV” living. From Marine Batteries to solar power, generators, hoses on Propane tanks, washing to get the “streaking off of it”. This is perfect.