How much solar do I need for my RV?

Short answer

An RV using about 2,000 Wh a day at 4.5 peak sun hours needs roughly 3 × 200 W panels · 195 Ah at 12.8 V · 70 A MPPT · 2,000 W inverter (2,500 W surge) — at least 562 W of panels.

How to work it out

Battery: 2,000 Wh × 1 days ÷ 80% usable ÷ 12.8 V = 195 Ah (2 batteries)
Panels: 2,000 Wh ÷ (4.5 sun h × 86% × 92% battery round trip) = 562 W → 3 panels
Controller: 600 W ÷ 12 V × 1.25 = 63 A → 70 A
Inverter: 1,500 W × 1.25 = 1,875 W → 2,000 W; surge: 1,500 W + (1,200 − 200) W = 2,500 W

Two kilowatt-hours a day is a comfortable boondocking budget: a 12 V compressor fridge, LED lights, the water pump and fans, phones and laptops, a TV in the evening and a few minutes of microwave. It does not include air conditioning.

Adjust for your project

Energy used per day

From the solar load calculator, inverter losses included.

Days of battery autonomy

Days the batteries cover with no sun.

Peak sun hours per day

Use your worst month for the season you need power in. See peak sun hours by city.

System voltage

Battery type

Sets how much of the rated capacity you plan to use: 80% for LiFePO4 (Victron rates cycle life at 80% depth of discharge), 50% for lead-acid (Trojan recommends 20–50% for long life).

Panel size

Most AC watts running at once

Add up what could run together (microwave + fridge + lights…).

Starting watts of the biggest motor (optional)

The largest motor or compressor’s starting watts, e.g. 800–1,200 W for a fridge (Champion chart).

Running watts of that motor (optional)

Its running watts (already counted in the peak above), e.g. 150–400 W for a fridge. The surge needed is the peak plus that motor’s extra starting watts.

More options: DoD · Headroom · Losses …

Usable depth of discharge (optional)

Blank uses 80% for LiFePO4 and 50% for lead-acid. Check your battery’s data sheet.

Headroom on controller and inverter

Your choice of margin so cold, bright days and long loads don’t run equipment at its limit.

System losses

Wiring, dirt, heat, mismatch and controller losses. 14% is the PVWatts default.

Coldest battery temperature

°F

Batteries hold less when cold: Victron gives about 80% for LiFePO4 at 32 °F (0 °C) and 50% at −4 °F (−20 °C); lead-acid about 86% at 32 °F. LiFePO4 must not be charged below 41 °F (5 °C) unless it is self-heating.

Your system3 × 200 W panels · 195 Ah at 12.8 V · 70 A MPPT · 2,000 W inverter (2,500 W surge)

Battery bank: 195 Ah · 12 V
12 V 100 Ah batteries: 2 batteries · LiFePO4
Solar array (minimum): 562 W
Panels: 3 panels · 200 W
MPPT controller output current: 70 A
Inverter continuous rating: 2,000 W
Inverter surge rating: 2,500 W
Battery current at peak AC load: 130 A

Before you wire itWire and fuse sizes come from NEC/ABYC ampacity tables and the equipment manual — have a qualified installer check them.

For this job · affiliate link

Battery monitor with shuntA shunt monitor on the bank is how you’ll know whether the system matches this plan in practice — especially in the first winter.

View on Amazon

The same system at other sun hours

The same system at other sun hours
Peak sun hours per day	Solar array (minimum)	Panels	MPPT controller output current
2	1,264 W	7 panels	146 A
3	843 W	5 panels	104 A
4	632 W	4 panels	100 A
5	506 W	3 panels	70 A
6	421 W	3 panels	70 A

What to know about RV solar

Roof space is the limit. Three 200 W panels fill much of a travel trailer roof once vents and the AC are in the way. More energy usually means more battery and a generator, not more panels.
Air conditioning is a different league. Champion’s chart puts a 13,500 BTU RV air conditioner at 1,500–2,000 running watts; a few hours of AC would need several times this system. That is a generator job — see what size generator for a 30 amp camper.
Flat panels lose winter output. RV roof panels often lie flat; in winter that costs a lot of output compared with tilting them toward the sun.
12 V suits many RVs. At the 1,500 W peak AC load, battery current is around 130 A — manageable on 12 V with two or more 100 Ah LiFePO4 batteries sharing it.

For your own numbers, total your appliances on the solar load calculator. The battery side is on how many watt-hours in a 200Ah battery and panel output on how much power a 200W solar panel produces per day.

Different size? Use the full Off-Grid Solar System Calculator.

What you’ll need

100 W solar panelMid-range price
The building block of most van, boat and RV systems. Check the data-sheet Voc and Isc before you decide how to wire several of them.
See options on Amazon (opens in a new tab)
MPPT solar charge controllerMid-range price
Converts a higher panel voltage into charging current, so you can wire panels in series and lose less in the cables. Size it on output amps and maximum PV voltage.
See options on Amazon (opens in a new tab)
12 V 100 Ah LiFePO4 batteryPremium price
About 1.28 kWh rated in a box roughly the size of a group 24–31 lead-acid battery at around half the weight. Check the BMS discharge limit and whether it can charge below freezing.
See options on Amazon (opens in a new tab)

As an Amazon Associate we earn from qualifying purchases. Links to products are affiliate links — they cost you nothing extra and help keep these calculators free.

Frequently asked questions

How much solar for an RV using 1 kWh a day?

About 2 × 200 W panels · 98 Ah at 12.8 V · 50 A MPPT · 2,000 W inverter (2,500 W surge).

How much solar for an RV with lead-acid batteries?

About 4 × 200 W panels · 333 Ah at 12 V · 100 A MPPT · 2,000 W inverter (2,500 W surge) — lead-acid needs a bigger bank and more panel for the same 2 kWh.

Other common sizes

An off-grid solar system for a house — 26 × 400 W panels, about 71 kWh of battery, 8,000 W inverter

Sources

National Laboratory of the Rockies (formerly NREL) — PVWatts® Calculator (opens in a new tab) — Look up the solar resource (peak sun hours) and yearly output for your own address; default system losses 14%.
NLR (formerly NREL) — PVWatts® v8 API, NSRDB PSM V3 TMY data (opens in a new tab) — City figures on this site: fixed open-rack array facing due south, tilted at the site’s latitude, 14% system losses, queried October 2026.
Victron Energy — Lithium Battery Smart manual, technical data (opens in a new tab) — LiFePO4 12.8 V: cycle life 2,500 at 80% DoD, 3,000 at 70%, 5,000 at 50% (to 80% of capacity); 92% round-trip efficiency; 12.8 V 100 Ah: recommended continuous discharge ≤100 A (1C), maximum 200 A; capacity about 20% lower at 0 °C; charge only between +5 °C and +50 °C.
Trojan Battery — Technical support FAQs (opens in a new tab) — “We generally recommend a discharge of 20 to 50% of the battery’s rated capacity even though the battery is capable of being cycled to 80%”; 20-hour and 100-hour ratings; freezing points by state of charge.
Trojan Battery — 27TMX data sheet (opens in a new tab) — Group 27 flooded: 85 Ah (5-hr), 97 Ah (10-hr), 105 Ah (20-hr), 117 Ah (100-hr); state of charge vs open-circuit voltage table; charger settings.
Victron Energy — Which solar charge controller: PWM or MPPT? (2020) (opens in a new tab) — MPPT output current = panel watts ÷ battery voltage (100 W ÷ 13 V = 7.7 A); a PWM controller pulls the panel down to battery voltage (81 W from a 100 W panel at 25 °C, about the same as MPPT at 75 °C); temperature-coefficient method; example panel Voc 21.6 V, −0.35 %/°C.
Victron Energy — Energy Unlimited (book) (opens in a new tab) — Lead-acid charge efficiency 80–95% (85% suggested as a starting value); battery energy efficiency about 75% for full cycles, about 89% in partial state of charge; inverter efficiencies above 90%.
Champion Power Equipment — Generator Wattage Chart (opens in a new tab) — Typical running and starting watts for household, RV and job-site appliances (a manufacturer’s planning chart — your nameplate wins).
U.S. Energy Information Administration — Electric Sales, Revenue, and Average Price, Table 5A (2024 data, released October 2025) (opens in a new tab) — 2024 average residential customer: 863 kWh a month (about 10,359 kWh a year, 28.4 kWh a day); Louisiana 1,202 kWh a month, Hawaii 495.