How many solar panels does an off-grid cabin need?

An off-grid cabin typically needs 4 to 8 solar panels rated at 400 watts each, depending on daily energy use and location. A basic cabin with lighting, a refrigerator, water pump, and electronics uses about 5 kWh per day and needs 4 panels at 5 peak sun hours. A cabin with more appliances using 10 kWh per day needs 7 to 8 panels.

How much does a complete off-grid solar system cost for a cabin?

A complete off-grid cabin solar system costs $3,000 to $8,000 for a DIY installation. A basic 1.6 kW system (4 panels, small battery bank, charge controller, inverter) costs $3,000 to $4,500. A larger 3.2 kW system (8 panels, bigger battery bank) costs $6,000 to $8,000. Professional installation adds $2,000 to $5,000 on top of equipment costs.

What size battery bank does a cabin need?

For a cabin using 7 kWh per day with 2 days of autonomy, you need about 17.5 kWh of usable battery capacity. With LiFePO4 at 80 percent depth of discharge, that is a 21.9 kWh total battery bank -- roughly 456 Ah at 48V. For a weekend cabin with 1 day of autonomy, you can get by with half that. Lead-acid batteries require twice the total capacity for the same usable energy.

Do solar panels work well in the mountains?

Yes, often better than at lower elevations. Higher altitude means thinner atmosphere and more direct solar radiation. A cabin at 7,000 feet can receive 5 to 15 percent more solar energy than a sea-level location at the same latitude. However, mountain locations also face more snow cover, shorter winter days, and potential shading from terrain and trees.

What happens to solar production at a cabin in winter?

Winter solar production drops 40 to 60 percent compared to summer at most US latitudes. Shorter days, lower sun angle, snow cover, and more cloud cover all reduce output. A system producing 8 kWh per day in July might produce only 3 to 4 kWh in December. Size your system for winter needs and you will have abundant surplus in summer.

Do I need a generator backup for an off-grid cabin?

A generator is strongly recommended for off-grid cabins, especially in northern locations with long winters. Even a well-sized solar system can fall short during extended cloudy periods or heavy snow. A 3,000 to 5,000 watt dual-fuel generator ($500 to $1,000) serves as insurance and can charge your battery bank when solar production is low. Many inverter-chargers have a generator input that automates this process.

Can I run a well pump on off-grid solar?

Yes. A typical 0.5 HP submersible well pump draws 500 to 750 watts and runs for 1 to 2 hours per day, using 0.5 to 1.5 kWh daily. This adds about 1 panel to your system. The startup surge (2 to 3 times running watts) requires an inverter rated for at least 2,250W surge. A pressure tank reduces pump cycling by storing pressurized water, which smooths out the power demand.

What is the best battery type for a cabin solar system?

LiFePO4 (lithium iron phosphate) is the best choice for most cabin systems. It offers 80 to 100 percent usable capacity, 3,000 to 5,000 charge cycles (10 to 15 year lifespan), lightweight construction, and no maintenance. The main drawback is cost -- roughly $400 to $600 per kWh. Lead-acid costs less upfront ($150 to $300 per kWh) but only lasts 3 to 5 years and provides only 50 percent usable capacity, making it more expensive over time.

How Many Solar Panels For An Off-Grid Cabin? (Complete Sizing Guide)

An off-grid cabin needs 4 to 8 solar panels (400W each) to cover daily energy use of 5 to 10 kWh. Combined with a battery bank, charge controller, and inverter, the complete system costs $3,000 to $8,000 for a DIY installation. This guide walks through every component you need, how to size each one, and what to budget for a reliable off-grid power system that handles everything from lighting to a well pump.

Quick Answer: Panel Count By Location

A typical off-grid cabin uses 5 to 10 kWh per day. Using 400W panels, 0.83 derate factor, and a mid-range 7 kWh/day target:

Peak Sun Hours	400W Panels Needed	System Size	Daily Output
3.5 PSH (winter in northern US)	8	3.2 kW	9.3 kWh
4 PSH (Pacific NW, Great Lakes)	7	2.8 kW	9.3 kWh
4.5 PSH (Mid-Atlantic, Midwest)	6	2.4 kW	9.0 kWh
5 PSH (US average)	5	2.0 kW	8.3 kWh
6 PSH (Southwest, Mountain West)	4	1.6 kW	8.0 kWh

Critical for cabins: If the cabin will be used year-round, size for winter production, not summer. A system that makes 8 kWh in July might only make 3.5 kWh in December. The table above uses annual average PSH -- for winter sizing, reduce your PSH by 40 to 50 percent and recalculate.

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Solar panel wattage

Type any value 10–750 W. Common sizes: 100 W (portable), 400 W (residential 2026), 580 W (commercial).

Peak sun hours per day

hrs

Don't know your PSH? Find your exact value →
Benchmarks: U.S. avg 4.98 · Phoenix 6.54 (highest) · Seattle 3.95 · Anchorage 3.17 (lowest). Above ~5.5 = sunny · 4.5–5.5 = average · below 4.5 = cloudy.

Daily kWh production

0.00kWh

Based on a 400W panel and 5.32 peak sun hours per day

Daily

1.60kWh

average across the year

Monthly

48kWh

× 30 days

Yearly

583kWh

× 365 days

Monthly production for a 400W panel — US Average

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

kWh per month · Source: NREL PVWatts v8

216 kg

CO₂ avoided per year

0.05

equivalent US homes powered

trees planted equivalent

$93

estimated annual savings

Tap to see sensitivity analysisSensitivity analysis

Sensitivity range
Scenario	Value
Low (-20%)	1.3 kWh
Expected	1.6 kWh
High (+20%)	1.9 kWh

Your daily production scales linearly with both panel wattage and peak sun hours. A 10% change in either input changes your result by 10%.

See production for your state Try the system size calculator

Typical Cabin Energy Use

Off-grid cabins use far less electricity than grid-connected homes because they typically rely on propane for cooking, heating, and hot water. The electric load centers on lighting, refrigeration, water pumping, and electronics.

Standard Cabin Load Table

Appliance	Watts	Hours/Day	Daily Wh
LED lighting (8 bulbs at 10W)	80	5	400
Refrigerator (efficient, 12V or AC)	80	8 (compressor run time)	640
Well pump (0.5 HP submersible)	600	1.5	900
Laptop	65	4	260
Phone chargers (2)	20	3	60
WiFi router / satellite internet	15	24	360
Ceiling fan (2 fans)	100	5	500
TV (40-inch LED)	55	3	165
Small appliances (blender, coffee grinder)	400	0.15	60
Washing machine (portable)	350	0.5	175
Total			3,520 Wh (3.5 kWh)

This is a minimal cabin. Adding any of these increases the load significantly:

Additional Load	Daily Wh Added
Electric water heater (tank or tankless)	1,500 - 3,000
Mini-split AC (0.75-1 ton)	1,500 - 3,000
Electric space heater	3,000 - 6,000
Chest freezer	400 - 700
Power tools (intermittent)	500 - 1,000
Starlink satellite internet	400 - 720

Rule of thumb: A propane-supplemented cabin with basic electric loads uses 4 to 6 kWh per day. An all-electric cabin with no propane uses 10 to 15 kWh per day or more.

Complete Off-Grid Equipment List

Here is everything you need for a reliable off-grid cabin solar system, with sizing recommendations for a 7 kWh/day target.

Solar Panels

System Size	Panels (400W)	Best For
1.6 kW	4	Weekend cabin, minimal loads, sunny climate
2.4 kW	6	Year-round use, moderate loads, average sun
3.2 kW	8	Year-round use, higher loads, or cloudy/northern location

Panel selection tips for cabins:

Choose monocrystalline panels for the best efficiency per square foot
Avoid cheap panels without a 25-year warranty from an established manufacturer
For ground-mounted systems, consider bifacial panels that capture reflected light from snow or light-colored ground -- they produce 5 to 15 percent more energy

Charge Controller

The charge controller regulates power from the panels to the battery bank, preventing overcharging and optimizing energy harvest.

System Size	Controller Type	Recommended Size
1.6 kW (4 panels)	MPPT	40A
2.4 kW (6 panels)	MPPT	50-60A
3.2 kW (8 panels)	MPPT	60-80A

Always choose MPPT over PWM for cabin systems. MPPT controllers harvest 15 to 30 percent more energy, especially in cold weather when panel voltage rises above battery voltage. This efficiency gain is equivalent to adding an extra panel for free.

Recommended brands: Victron SmartSolar, Midnite Classic, Renogy Rover. Expect to pay $200 to $600 depending on amperage.

Battery Bank

Autonomy	Daily Use	LiFePO4 Capacity (48V)	Lead-Acid Capacity (48V)	Est. Cost (LiFePO4)
1 day	7 kWh	182 Ah (8.75 kWh)	292 Ah (14 kWh)	$2,500 - $3,500
2 days	7 kWh	365 Ah (17.5 kWh)	583 Ah (28 kWh)	$5,000 - $7,000
3 days	7 kWh	547 Ah (26.25 kWh)	875 Ah (42 kWh)	$7,500 - $10,500

Choose 2 days of autonomy for most locations. In the desert Southwest with consistent sun, 1 day works. In the Pacific Northwest or northern mountain states, consider 3 days.

LiFePO4 is the clear winner for cabin use: lighter weight, deeper discharge, longer life, and no maintenance. The higher upfront cost is offset by the 10-15 year lifespan versus 3-5 years for lead-acid.

Inverter

The inverter converts DC battery power to AC household power (120V, 60 Hz).

Cabin Type	Inverter Size	Surge Rating
Basic (lights, fridge, electronics)	2,000W	4,000W
Standard (add well pump, washing machine)	3,000W	6,000W
Full-featured (add power tools, AC)	5,000W	10,000W

Choose a pure sine wave inverter. Modified sine wave inverters are cheaper but can damage sensitive electronics, cause buzzing in audio equipment, and reduce motor efficiency. An inverter-charger model with a generator input is ideal -- it automatically switches to generator power and charges the batteries when solar falls short.

Seasonal Considerations

Off-grid cabins face a fundamental challenge: energy demand often peaks when solar production is lowest.

Winter Production Drop

Location	Summer Daily Output (2.4 kW system)	Winter Daily Output	Drop
Flagstaff, AZ (7,000 ft)	11.5 kWh	6.5 kWh	43%
Denver, CO (5,280 ft)	10.8 kWh	5.2 kWh	52%
Boise, ID	10.5 kWh	4.0 kWh	62%
Burlington, VT	9.5 kWh	3.0 kWh	68%
Anchorage, AK	8.5 kWh	1.5 kWh	82%

Winter strategies:

Oversize the array for winter. If you need 7 kWh/day and winter production drops 50%, you need a system that produces 14 kWh in summer. That is 8 panels instead of 4.
Tilt panels for winter sun. Setting the tilt angle to latitude plus 15 degrees optimizes winter capture. Adjustable ground mounts let you change tilt seasonally.
Keep panels clear of snow. Steep tilt angles (45+ degrees) help snow slide off. A soft-bristle roof rake works for manual clearing.
Use a generator as backup. Running a generator 2 to 4 hours on the worst days to top off batteries is far cheaper than doubling your solar array for a handful of cloudy winter weeks.
Reduce winter loads. Switch to propane for water heating, use propane or wood for space heating, limit discretionary loads.

Ground Mount vs Roof Mount

For cabins, ground-mounted panels often make more sense than roof-mounted:

Factor	Ground Mount	Roof Mount
Installation	Easier DIY, no roof penetrations	Requires roof work, potential leak risk
Angle optimization	Adjustable tilt for seasonal changes	Fixed to roof pitch
Snow clearing	Easy to reach and brush off	Difficult and dangerous on a steep roof
Shading	Can place in optimal location away from trees	Limited by cabin position and surrounding trees
Cost	10-20% more (concrete piers or posts needed)	Less material cost
Aesthetics	Visible in yard	Less obtrusive
Wildlife	Critters can nest underneath (use wire mesh)	Squirrels may chew wiring (also use mesh)

For wooded cabin sites, a ground mount 50 to 100 feet from the cabin in a sunny clearing is often the only way to avoid tree shading. Run buried conduit from the array to the cabin's electrical panel.

Sample Budgets

Weekend Cabin -- Basic ($3,000 - $4,500)

4 x 400W panels (1.6 kW)
40A MPPT charge controller
48V 100Ah LiFePO4 battery (4.8 kWh)
2,000W pure sine wave inverter
Ground mount racking (4 panels)
Wiring, breakers, conduit
Covers: lights, fridge, phone/laptop charging, small TV

Year-Round Cabin -- Standard ($5,500 - $7,500)

6 x 400W panels (2.4 kW)
60A MPPT charge controller
48V 200Ah LiFePO4 battery bank (9.6 kWh)
3,000W inverter-charger with generator input
Adjustable ground mount racking
Complete wiring with subpanel
Covers: all basic loads plus well pump, washing machine, power tools

Year-Round Cabin -- Premium ($7,500 - $12,000)

8 x 400W panels (3.2 kW)
80A MPPT charge controller
48V 400Ah LiFePO4 battery bank (19.2 kWh)
5,000W inverter-charger
Adjustable ground mount with snow-shedding tilt
Full electrical panel, monitoring system
Optional: 3,000W dual-fuel generator ($500 - $800)
Covers: all loads including seasonal mini-split AC, heavier tool use

Generator Backup

Even the best-designed off-grid cabin solar system benefits from a generator backup. Extended cloudy periods, unexpected heavy loads, or winter shortfalls are all manageable with a small generator.

Recommended generator size: 3,000 to 5,000 watts. This charges a 48V battery bank at 30 to 50 amps through your inverter-charger's built-in AC charger.

Fuel options:

Gasoline: cheapest generators, widely available fuel, but stale fuel is a problem for seasonal cabins
Propane: stores indefinitely (ideal for cabins), cleaner burning, quieter
Dual-fuel (gas + propane): maximum flexibility, best for remote cabins

Fuel consumption: A 3,500W inverter generator uses about 0.5 gallons of gasoline per hour at 50% load. Running it for 3 hours charges about 4 to 5 kWh of battery capacity -- roughly a full day's worth of cabin energy. A 5-gallon fuel can provides about 30 hours of generation, enough to bridge a week-long cloudy stretch.