Solar sizing for a live camera, step by step

Most solar camera failures have the same cause: the system was sized for an average day, and the camera goes dark on the short, cloudy days of winter. The fix is simple arithmetic with good sunlight data. This guide walks through it with real numbers for eight places, from Hawaii to Alaska, using NASA’s POWER climate data (2001 to 2020 averages) for panels tilted toward the equator.

Step 1: Add up the daily load

List everything that runs from the battery, its average power and the hours it runs. Then add 10 to 20 percent for conversion losses. Our example is a typical remote live camera:

If you can measure your actual setup with a DC power meter for a day or two, do it. Infrared at night, heaters in winter and PTZ movement can raise the real figure well above the label.

Step 2: Find your darkest month

Solar designers talk about “peak sun hours”: the daily solar energy on the panel, in kWh per square meter, which equals the hours of full 1,000 W/m² sunshine it is worth. It depends on latitude, climate and how the panel is tilted. Free tools give it for any spot on Earth: NASA POWER (monthly averages by coordinates) and NREL’s PVWatts.

The chart shows monthly sun hours for panels tilted at latitude + 15°, a common winter-friendly tilt, in four US places.

Notice that sunny, high Denver keeps over 4 sun hours even in December, while Seattle drops to under 2 because of clouds as well as latitude. Latitude alone does not tell the story; use real data for your spot.

Step 3: Size the panel

Panel watts = daily load (Wh) ÷ (darkest-month sun hours × 0.75)

The 0.75 factor covers the gap between a panel’s label and real life: heat, dust, wiring, controller and battery losses. For our 220 Wh load:

The “practical choice” rounds up for panel ageing, dirty panels and runs of dull days. In the Southern Hemisphere the worst month is June, and the panel faces north.

Same sites, different seasons

If your camera only needs to run in summer (a beach season, a ski season in reverse, a nesting season), size for that season’s worst month instead. The yearly average is a poor guide in either case:

Yearly averages here use a panel tilted at latitude (NASA POWER). The further from the equator, the more dangerous it is to size by the average.

Step 4: Size the battery

The battery carries the camera through nights and dull days. Decide how many days of autonomy you want: two to three in sunny climates, five or more in cloudy or high-latitude winters. Then:

Battery Wh = daily load × days of autonomy ÷ usable share

Lithium iron phosphate (LiFePO4) batteries can use about 80 to 90 percent of their capacity; lead-acid batteries last much longer if you use only about half. Using 80 percent for LiFePO4:

A common 100 Ah 12 V lithium battery holds 1,280 Wh, about 4.6 days of our 220 Wh load at 80 percent use. Lithium batteries must not be charged below freezing unless they are heated or the controller blocks cold charging. In cold places, put the battery in an insulated box or choose a heated model.

Step 5: Pick the charge controller

An MPPT controller gets more from the panel than a basic PWM one, especially in cold weather. Size its current for the panel: controller amps ≈ panel watts ÷ battery volts × 1.25. A 100 W panel on a 12 V battery needs about 10 A; a 200 W panel, about 20 A. Check that the panel’s open-circuit voltage on the coldest morning stays below the controller’s maximum PV voltage. A controller with a load output and low-voltage cut-off protects the battery from being drained flat.

Step 6: Place the panel well

• Face the equator: south in the Northern Hemisphere, north in the Southern.
• Tilt for winter: about latitude + 15° favors winter and sheds snow better.
• No shade in winter: check the sun’s low winter path. A tree or roof that is harmless in June can shade the panel all December day. See where to mount a camera for winter sun angles.
• Mind the wind: a panel on a pole is a sail. See mounting on poles.

Worked example 2: adding a satellite dish

Where there is no cellular signal, a satellite terminal can be the only internet. The Starlink Mini spec sheet lists 25 to 40 W average. With a 30 W average plus the camera:

• Daily load: (30 W + 4.4 W) × 24 h = about 826 Wh, plus 15 percent losses = about 950 Wh.
• Panel in Phoenix (5.26 sun hours): 950 ÷ (5.26 × 0.75) = about 240 W.
• Panel in Denver (4.48): about 280 W.
• Panel in Seattle (1.76): about 720 W.
• Battery for three days: 950 × 3 ÷ 0.8 = about 3,560 Wh, roughly 280 Ah at 12.8 V.

That is four times the camera-plus-4G system. If any cellular signal exists, even weak, a directional antenna on a 4G router is usually far cheaper to power. Some owners run the dish only during daylight or on a schedule, which cuts the load a lot. See internet for remote cameras.

When solar is not enough

At high latitudes (Anchorage, northern Scandinavia, much of Canada) a December solar system for a 24/7 camera becomes very large. The options are: accept a winter schedule (snapshots every 15 minutes instead of live video), add a wind turbine, add a fuel cell or generator, or bring in grid power. Many mountain and Arctic webcams use exactly these compromises.

Common sizing mistakes

• Using the yearly average. The system runs fine until November, then dies for weeks. Always size for the worst month you need.
• Trusting the camera’s “typical” power. Night infrared, heaters and the router are often left out. Measure, or use maximum figures.
• Forgetting conversion losses. A 12 V to PoE converter, a controller and long thin wires can waste 10 to 20 percent.
• Too few battery days. One stormy week drains a two-day battery. Cloudy climates need five or more.
• Shade you did not see. A pole, branch or roof edge across part of a panel can cut its output sharply. Check the winter sun path.
• Flat panels. A panel lying flat collects dirt and snow and catches little low winter sun. Tilt it.
• Cold charging. Lithium batteries charged below freezing can be damaged. Use a low-temperature cut-off or a heated battery.

Keep an eye on it

A solar camera should report its own health. Many charge controllers have Bluetooth or a data port; some routers can read the battery voltage. Watch three numbers through the first winter: the battery’s lowest morning voltage, how full it gets by evening, and how many days it takes to recover after a storm. If it never reaches full in December, add panel. If it recovers but runs low after long storms, add battery. Clean the panel in autumn, and check cable connections once a year: loose terminals cause more failures than panels do.

Parts for a camera-sized solar system

Specs below are the makers’ own. Price checked 2026-10-07 on the maker’s store.

Do these next

1. Get your own sun hours from NASA POWER for your exact spot.
2. Check your load and the power options again.
3. Price the system and compare with bringing in grid power.

Last reviewed October 7, 2026 by the LiveLocation team. General information, not legal or electrical advice.