Electrical
Shore power, batteries, solar and everything that draws from them.
- 47 guides
- 11 calculators
- Updated
Start here
Where most readers begin
-
RV Battery Calculator: How Many Amp Hours, Batteries and Inverter Watts You Need
Tick your appliances and hours to get daily watt-hours, the amp-hour bank that covers it in lithium or AGM, the inverter that clears your biggest load, and the batteries that make that bank.
Updated
Shore power & surge protection
30 vs 50 amp, what you can run at once, and the surge protectors and EMS units that stand between the pedestal and the rig.
-
RV Amp Draw Calculator: What Can You Run at Once on 30 or 50 Amp?
Estimate running amps and startup loads on 30A or 50A RV service, then download your appliance amp-draw card as a Letter or A4 PDF.
Updated -
RV Extension Cord Calculator: How Long Can a 30 Amp Cord Be?
Work out the voltage your RV actually gets through its shore cord and an extension — counting the round trip, the coiled slack, and the drop a portable EMS at the pedestal never sees.
Updated -
EMS vs Surge Protector: Which Does Your RV Actually Need?
Compare spike suppression, automatic voltage shutoff and fault indicators. Diagrams explain trip and reconnect delays, with model-specific checks for choosing RV power protection.
Updated -
Surge Guard vs Progressive Industries: Which 30 Amp EMS?
Compare the PT30X and 34930 voltage-trip timing, reconnect delays, local displays and warranty conditions using their manufacturer documentation.
Updated -
Hardwired vs Portable RV Surge Protector: Which Should You Fit?
Portable units get stolen and rained on. Hardwired units have to be uninstalled to claim a warranty. The trade-offs nobody spells out, and how to decide.
Updated -
Progressive Industries vs Hughes Power Watchdog: Which 30 Amp EMS?
The two leading 30 amp RV surge protectors compared on published specifications. One protects better per pound spent; the other tells you more about what the pedestal is doing.
Updated -
9 Mistakes People Make Buying an RV Surge Protector
Joule ratings mislead, transfer switches are not protectors, and every major warranty in this category is narrower than its name. What we found reading the manufacturers' own documents.
Updated -
30 Amp vs 50 Amp RV: What the Difference Actually Means
A 50 amp RV gets more than three times the power of a 30 amp one, not 67% more. How to tell which you have, what each will run, and what adapters do and do not give you.
Updated -
Do I Need a Surge Protector for My RV?
Probably — but first check whether your rig already has one, because a transfer switch is not the same thing. Plus the insurance gap that makes this decision cost more than it looks.
Updated -
RV Surge Protector Error Codes Explained
What each EMS error code means, taken from the manufacturers' own charts — Progressive Industries E-codes and Surge Guard LCD messages — plus what to do about each one.
Updated -
Why Does My RV Breaker Keep Tripping?
Most tripping RV breakers are a load problem, not a fault. How to tell an overload from a genuine fault, work out which breaker is actually tripping, and know when to stop and call an electrician.
Updated
Batteries & charging
Lithium or AGM, how much capacity you need, and how the bank gets charged — converter, DC-DC or cold-weather limits.
-
RV Battery Calculator: How Many Amp Hours, Batteries and Inverter Watts You Need
Tick your appliances and hours to get daily watt-hours, the amp-hour bank that covers it in lithium or AGM, the inverter that clears your biggest load, and the batteries that make that bank.
Updated -
RV Battery Charge Time Calculator: How Long to Full?
Work out how long your bank takes to charge from your own numbers — bulk and absorption separately, and whether your converter or your battery is the thing setting the pace.
Updated -
Battle Born vs Dakota Lithium: Which 100Ah RV Battery?
Battle Born and Dakota Lithium compared at 100Ah: tray fit, heating, surge ratings and warranties, with conflicting temperature limits and missing heater figures explained.
Updated -
Lithium vs AGM RV Batteries: Which Should You Actually Buy?
Most comparisons of these two are published by lithium manufacturers. Here is where lithium genuinely wins, where AGM still does, and what switching really costs once the charger is included.
Updated -
What Size Lithium Battery Do I Need for My RV?
"Size" means two different things — the case that has to fit your tray, and the capacity that has to last the night. Published dimensions for real batteries, and the arithmetic for amp hours.
Updated -
Do I Need a DC to DC Charger for My RV?
The RV forums genuinely disagree about this one. The answer turns on four things you can check — your alternator type, your battery chemistry, your cable run and how long you drive.
Updated -
Charging RV Lithium Batteries in Cold Weather
Compare lithium battery charging and discharge temperature windows, understand cold-charge protection, and plan for the energy used by a heated battery.
Updated
Battery monitoring
Shunts and monitors, and how far to trust the percentage on the screen.
-
RV Battery State of Charge Calculator: What Your Voltage Reading Is Worth
Interpret a 12V battery reading, see an illustrative load correction and learn when a rested-voltage reference can support a rough state-of-charge estimate.
Updated -
Victron SmartShunt vs BMV-712 Smart
Compare the local display, alarms and control paths. Both estimate battery charge; the BMV adds a small relay, while SmartShunt control needs extra hardware.
Updated -
Do You Need a Shunt If Your Battery Has Bluetooth?
Depends entirely on which kind of Bluetooth battery you bought — and the word "smart" covers three products that answer this differently. Victron sells two of them, with opposite answers.
Updated -
What Size Shunt Do You Need for a Battery Monitor?
A shunt has two ratings, not one — full-scale amps and the millivolts it puts out at that current. Get the second wrong and every reading is quietly scaled by a fixed factor.
Updated
Solar
Panels, charge controllers and fusing, sized for the month you actually camp in.
-
How Much Solar Do I Need for My RV? Sized for the Month You Camp In
Size RV solar for your camping month and roof space using NASA's monthly sun data. Download a Letter/A4 peak-sun-hours chart for 14 U.S. destinations.
Updated -
Is Tilting RV Solar Panels Worth It? The Gain by Month and Place
On NASA's data, tilting RV panels adds 37% to 93% in December from Orlando to Seattle, and loses 10% to 16% in June. Work it out for your panels and month.
Updated -
What Size Fuse Between Solar Panel and Charge Controller? An RV Fuse Calculator
Size every fuse in an RV solar system from your own panels: the strings, the array to the controller, and the controller to the battery, by the makers' figures.
Updated -
What Size Solar Charge Controller? The Cold-Morning Voltage Nobody Checks
Size an MPPT controller on the two figures that can damage it — cold open-circuit voltage and short-circuit current — not on watts, which Victron says it simply limits.
Updated -
Flexible vs Rigid RV Solar Panels: What the Warranties and Manuals Say
Rigid or flexible is three choices, not two, and the warranty gap everyone quotes is not what the makers' documents say. Here is what they do say.
Updated -
Victron vs Renogy Charge Controller
Both are 100 V MPPT controllers rated at 98%, so the efficiency gap most comparisons quote is not in either manual. Here is what actually differs.
Updated -
RV Solar Prep: What Your Factory Port Is Wired To
Solar prep is wiring, not panels, and makers disagree about what plugs into it. How to tell which port you have, what it runs to, and test it first.
Updated -
RV Solar Panel Not Charging the Battery
Most guides list causes. Four readings from the controller makers' own manuals tell you which one you have, starting with whether the battery is full.
Updated
Inverters, generators & wiring
Running 120V loads away from hookups, from inverter and generator sizing to cable gauge.
-
12V Wire Size Calculator: Gauge, Voltage Drop and Fuse Size
Size DC cable for an inverter, a DC-DC charger or any 12V circuit. Shows the gauge voltage drop needs, the gauge ampacity needs, which one binds — and whether it will fit your device's terminals.
Updated -
What Size Generator for an RV Air Conditioner? (Altitude and Heat Included)
Size an RV generator from Dometic's guideline, altitude and heat. Compare peak watts with running output, and see where manufacturer derating data is missing.
Updated -
Victron vs Renogy Inverters: The Real Difference
One sells you an inverter, the other sells you a power system. Compared on published output, idle draw, warranty structure and what each purchase actually commits you to.
Updated -
Inverter vs Inverter/Charger: Which Does Your RV Need?
One makes 120V from your batteries. The other also replaces your converter and switches automatically between shore and battery. Your existing converter decides which one you buy.
Updated -
What Size Inverter Do I Need for My RV?
Three numbers size an RV inverter — your biggest simultaneous load, its startup surge, and what your battery bank's BMS will actually pass. Most guides stop after the first one.
Updated -
Can You Run an RV Air Conditioner on Batteries?
Separate compressor startup from running energy, check inverter and battery current limits, and estimate how long an RV air conditioner can run on a bank.
Updated -
Do You Need a Pure Sine Wave Inverter for Your RV?
Usually yes — the price gap has collapsed. But the honest answer depends on your load list, and the published distortion figures show exactly what the modified sine discount buys.
Updated