Shore power or a generator feeds the 120 volt side of your RV. The converter uses that to charge the 12 volt battery, and the battery runs the lights, pump and controls. An inverter turns battery power back into 120 volts when you are unplugged, and solar charges the battery.
RV Batteries and Power Explained: Shore Power, Converter, Battery and Inverter
On this page (4)
What runs on 12 volts and what on 120 volts
The quick rule: anything that would work in a car runs on the 12 volt battery side, and anything you would plug into a wall at home needs 120 volts from the pedestal, a generator or an inverter.
| Side | Typically runs |
|---|---|
| 12 volt, from the battery | Ceiling and exterior lights, water pump, furnace fan and ignition, propane and carbon monoxide alarms, slide and awning motors, fridge controls, USB outlets |
| 120 volt, from shore power, generator or inverter | Air conditioner, microwave, wall outlets, TV, electric water heater element, residential refrigerator |
That split is the one described in RV owner's manuals; your own manual and the labels inside the power center list the circuits your model actually has, including whether your cord is a 30 amp or 50 amp service.
Tip: The battery sits in the middle of everything. Plugged in, the converter keeps it topped up and you barely notice it. Unplugged, every light, fan and control draws from it, which is why battery capacity is usually the first thing owners upgrade.
Which page covers the part you need
Each power page answers one question and sizes one part:
- 30 amp vs 50 amp shore power: which pedestal service your RV takes, and what it limits.
- RV surge protectors: what a pedestal protector guards against before you plug in.
- The RV converter: how shore power becomes 12 volt charging.
- RV battery types compared: flooded, AGM and lithium side by side.
- Switching an RV to lithium: what else has to change with the battery.
- How an RV battery charges: converter, alternator and solar, and the charge stages.
- How to connect RV batteries: series and parallel wiring.
- The battery disconnect switch: what it cuts and what stays live.
- What size inverter your RV needs: sizing from what you want to run.
- RV solar sizing: panel watts against your daily use.
- Solar generators for RVs: portable power stations against a built in system.
- What size generator an RV needs: starting and running watts for the air conditioner.
Tip: An inverter does not make power, it spends the battery. A big inverter with a small battery bank will run the microwave for a few minutes and then leave you with nothing for the furnace overnight. Size the bank first.
Where to stop and call a professional
The 12 volt side is owner territory: fuses, battery terminals, a disconnect switch, a portable panel.
Anything on the 120 volt side behind the panel is not. Wiring in a new converter or inverter, changing the shore power inlet or breakers, or a lithium conversion that changes how the battery is charged are jobs for a licensed electrician or a certified RV technician. Mistakes there start fires and are not visible until they do.
Power is only one of the systems
This hub covers the electrical supplies only. The appliances themselves, propane and the water system are on the RV systems hub, including which appliances run on propane rather than electricity. For propane handling and tank rules, the Propane Education and Research Council is the industry source.
All guides in this section
- 30 Amp vs 50 Amp RV Shore Power: What Each Runs and the Adapters
The difference between 30 amp and 50 amp RV service, what each can run, the plugs, adapters and dogbones, and why an adapter does not add power.
- How an RV Battery Charges: Shore Power, Generator, Solar and the Truck
How an RV battery charges from shore power, a generator, solar and the tow vehicle, how to tell when it is full, and charging a flat or stored battery.
- How to Connect RV Batteries: One Battery, 12 V in Parallel, 6 V in Series
How to hook up an RV battery safely and in what order, and how to wire two 12 V batteries in parallel or two 6 V in series, from battery makers' guides.
- RV Battery Types: Flooded, AGM and Lithium Compared
Flooded, AGM and lithium RV batteries compared by usable capacity, weight, cycle life, charging and cold weather, from the makers' own spec sheets.
- RV Solar Sizing: How Many Watts, What Battery, Which Charge Controller
How many solar watts an RV needs, worked from what you use each day and the sun where you camp, plus the battery and charge controller to match.
- RV Surge Protectors and EMS Units: What They Catch, 30 vs 50 Amp
What an RV surge protector does, how an EMS differs, the faults each catches, 30 vs 50 amp versions, and portable vs hardwired, from the makers' manuals.
- Solar Generators for RVs: What Portable Power Station Specs Mean
What a solar generator (portable power station) is, what watt-hours, inverter watts and inputs mean, and what each size runs in an RV, from makers' specs.
- Switching Your RV to Lithium: The Converter, Charging and Cold Rules
What changes when you put a lithium battery in an RV: the converter or charger setting, solar and alternator charging, the battery monitor and cold limits.
- The RV Battery Disconnect Switch: What It Cuts and When to Use It
What the RV battery disconnect switch cuts and what stays powered, whether the battery charges with it off, storage use, and isolators in motorhomes.
- The RV Converter: What It Does, Signs It Is Failing, Replacing It
What the RV converter does, how it charges the battery, the signs it is failing and how to check it, sizing a replacement, and lithium charging.
- What Size Generator Does an RV Need? Watts for the AC, 30 vs 50 Amp
How to size a generator for an RV: the air conditioner's starting watts, what a 30 or 50 amp RV can draw, inverter vs open-frame, and running it safely.
- What Size Inverter Does Your RV Need? Watts, Surge and the Battery Behind It
How to size an RV inverter from what you run at once, why pure sine wave matters, and the battery bank and cables a big inverter needs.