Should an RV Inverter Be Left on When Plugged In?
Generally, RV inverters should be turned off when not in use to avoid unnecessary battery drain. However, whether an RV inverter should be left on or off when plugged in depends on several factors, primarily the type of inverter and the manufacturer’s recommendations.
In this comprehensive guide, we’ll look in-depth at how RV inverters work, whether to leave them on when plugged in and the steps for proper use and maintenance.
Read on to gain a complete understanding of RV inverters and best practices for their operation.
How Does an RV Inverter Work?
RV inverters transform the 12-volt DC power supplied by your RV’s battery bank into 120-volt AC power. Here is a simple overview of how RV power inverters function:
- The inverter draws 12V DC electricity from your RV’s battery bank.
- The circuitry inside the inverter takes this incoming 12V DC power and boosts the voltage.
- Additional circuitry converts the boosted DC voltage into 120V AC power. This conversion process is called “inversion”, hence the name inverter.
- The 120V AC electricity output from the inverter can then be used to power any 120-volt AC appliances, electronics, or outlets in your RV.
So, an RV inverter takes the low voltage 12V DC power stored in your RV’s batteries and converts it into the 120V AC power required to operate your microwave, TV, outlets, etc, when shore power is unavailable.
The DC-to-AC conversion in an RV inverter can be of two types:
- Modified Sine Wave: Less expensive but can produce audible noise in some devices. Okay for most RV uses.
- Pure Sine Wave: Provides cleaner “pure” AC power. Recommended for sensitive electronics. More expensive.
Pure sine wave inverters provide power quality closest to what you get from your home outlets and are generally preferred when running electronics.
Should You Leave an RV Inverter on When Plugged Into Shore Power?
Unfortunately, there is no definitive “yes” or “no” answer that applies equally to all RV inverter installations. There are pros and cons to both options that depend on your specific RV setup and which type of inverter you have.
Let’s examine the key factors to consider when deciding whether to run your RV inverter while connected to shore power:
Reasons to Leave Inverter ON When Plugged Into Shore Power
- Continuously Powers Appliances if Shore Power Is Lost – Leaving the inverter on provides uninterrupted AC power to your devices and outlets if the incoming power supply fails or is disconnected.
- Allows Use of Battery Power Instead of Shore Power – This can help reduce stresses on utilities at crowded campgrounds by utilizing your battery bank first before drawing from shore power.
- May Be Needed for Residential Refrigerators to Stay On – Most RV residential fridges require the inverter to be left on at all times, even when shore power is available, to ensure continuous operation.
- Required for Power Assist on Small Electrical Supplies – An RV inverter left on can augment an undersized shore power hookup using battery power.
- Keeps Batteries Charged if Equipped With Dual Inverter/Charger – Dual units use shore power to charge batteries while also supplying inverted AC power from batteries as needed.
- Maintains Continuous Power to Maintain Electronic Device Settings – Keeping an inverter on provides uninterrupted AC to maintain settings on devices like alarm clocks, microwaves, etc.
Reasons to Turn Inverter OFF When Plugged Into Shore Power
- Saves Wear and Tear on Inverter – Leaving the inverter off while plugged into shore power reduces unnecessary runtime hours which contributes to long-term reliability.
- Prevents Draining Batteries While Connected to Shore Power– An RV inverter consumes power when left on, even in standby mode. This drains batteries over time.
- Some Manufacturers Recommend Turning the Inverter Off – Check your user manual, as some brands advise turning the inverter off to conserve battery power when shore power is available.
- Allows Batteries to Charge Faster From the Converter – With the inverter off, the RV converter can focus on recharging batteries faster instead of charging and supplying AC power loads.
- Eliminates Potential Interference With Shore Power – Very small possibility that two AC power supplies while connected to shore power could cause electrical issues.
- Simpler to Just Use Shore Power – Some RV owners find it easier and less confusing to simply use shore power directly when available instead of running an inverter.
- Conserve Battery Power – Turning off the inverter reduces any parasitic draw when shore power is available, preserving your battery bank.
As you can see, there are good arguments both for and against leaving your RV inverter switched on when plugged into shore power.
There is no universally correct choice, so you must consider your specific inverter setup and usage factors.
What to Do When Using a Generator with an RV Inverter
When boondocking with an RV generator, you technically don’t need the inverter to provide 120V AC power. However, there are a couple of benefits to leaving it on:
- If there is an issue with generator power, the inverter seamlessly takes over so that your appliances continue to receive uninterrupted power.
- For generators without automatic start, the inverter avoids manual restarts if the gen shuts off at night.
If powered off, the inverter would require a manual restart to provide power when the generator stops. Leaving it on ensures uninterrupted 120V.
What to Do When Using RV Inverters with Solar Panels
RV solar panels produce 12V DC power that charges your battery bank. With an inverter, you can use the energy from your solar panels to run AC appliances and devices.
When boondocking and relying on solar to supply power to the RV, it is best to leave the inverter turned on 24/7.
That way the solar power seamlessly flows to the batteries and through the inverter to power AC devices as needed. No user intervention is required.
How to Decide For Different Types of RV Inverters
There are three main types of RV power inverters:
Standalone or portable RV inverters are not wired into the RV. They simply plug into your RV’s 12-volt cigarette lighter or accessory outlet.
Portable inverters generally are used for relatively low-power applications, usually between 150 to 1000 watts. They have one or two standard household 120-volt AC outlets on them that you can plug devices directly into.
Portable inverters provide an easy way to add a small inverter to any RV, allowing you to operate a couple of small devices off your battery bank. They are ideal for occasional use or light-duty applications.
Shore Power Consideration:
When connected to shore power, it’s generally advisable to turn off standalone inverters. These inverters are not designed for continuous operation, and leaving them on can drain your RV’s battery bank unnecessarily.
Built-in/Hardwired RV Inverters
Many newer RVs come equipped with a built-in or hardwired RV power inverter. These inverters are permanently installed and wired directly to your RV’s house battery bank.
Built-in RV inverters are generally higher capacity, usually between 1000 to 4000 watts. The inverter will have a control panel installed inside the RV to turn it on and off as needed.
Often built-in inverters are either wired to specific receptacles and circuits in your RV or connected to a dedicated circuit breaker box that handles multiple 110-volt circuits.
Shore Power Consideration:
Built-in inverters are more integrated into your RV’s electrical system. Whether to leave them on or off when connected to shore power can depend on several factors.
For example, if your RV setup has a sophisticated battery management system that can prioritize shore power, leaving the inverter on might not drain the battery. However, turning it off can reduce wear and tear.
Inverter/Charger Combo Units
Some newer RVs feature an inverter and battery charger combo unit. These inverters provide both the inverting function that converts battery power to AC power, and a charging function that can recharge your batteries when plugged into shore power.
Many inverter/charger combo units are dual unit inverters, meaning they can use shore power to charge batteries while also inverting battery power to AC if needed.
Shore Power Consideration:
If your RV is equipped with a dual inverter/charger combo unit, you most likely will want to leave this on at all times.
Dual inverter/chargers provide both inverted battery power and battery charging functionality in one device. The charger portion will charge the RV house batteries from shore power, while the inverter side can provide AC electricity from the batteries as needed.
These dual units are designed to remain on continuously, both while plugged into shore power and when off-grid running on battery power only.
The manufacturer’s guidelines for dual inverter/charger combo units will specify to leave the inverter switched on at all times. This allows uninterrupted battery charging and AC power delivery as needed.
Testing Your RV Inverter
Before making a final decision on whether to leave your particular RV inverter on or off when shore power is available, it’s a good idea to run some tests once fully hooked up:
- Check Battery Voltage Periodically Over a Few Hours With the Inverter On – Monitor your RV battery bank voltage with a multimeter. Leaving an inverter on tends to drain around 0.5-1 volt. If you see larger drops, that indicates a problem. Properly sized batteries paired with a dual inverter/charger should see minimal voltage drop.
- Feel Inverter to Check Temperature – Under normal conditions, leaving an inverter on should not cause excess heat buildup. Turn it off if it becomes abnormally hot.
- Plug in and Check AC Appliances – Make sure turning the inverter on does not cause issues with appliances or electronics plugged into shore power. Try cycling the inverter on and off while using different devices.
- Assess Shore Power Pedestal Current – Use an ammeter to see if the RV’s total shore power amp draw rises significantly with the inverter on versus off. Spikes could indicate a problem.
These kinds of tests will help assess how your particular RV’s electrical system handles leaving the inverter turned on when hooked up to shore power.
Monitor for warning signs like rapid battery drain, overheating, electrical interference, or sudden high current draws.
Any issues that arise may indicate a problem with your specific inverter installation or a conflict with the particular pedestal power supply. Always correct any problems discovered before continuing to run your inverter long-term.
Safety Precautions When Operating RV Inverters
Before deciding to leave your RV inverter on constantly when plugged in, be sure to take some basic safety precautions:
- Double Check Polarity – Make sure DC and AC wiring is correctly polarized. Reverse polarity can destroy inverters and pose serious hazards.
- Ensure Sufficient Ventilation – Inverters produce heat and need adequate airflow. Do not cover or block ventilation openings.
- Turn Off Before Disconnecting From Shore Power – Always power down the inverter before unplugging from shore power to prevent spikes or surges.
- Use Recommended Wire Gauges – Undersized cables can overheat. Follow manufacturer guidelines for wiring and circuit protection.
- Keep Sparks Away From Batteries – Working near RV batteries can produce dangerous sparks. Take proper precautions.
- Avoid Excessive Loads – Do not exceed the inverter’s rated wattage capacity. Overloads can severely damage inverters.
- Check Shore Power Pedestal Condition – Use a properly grounded, dedicated 30A/50A RV outlet in good condition.
- Monitor Battery Voltage – Running batteries too low will damage them. Recharge before depletion.
By taking the proper electrical safety measures and following your particular inverter manufacturer’s guidelines, you can minimize any risks that may arise from extended inverter operation.
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