Guide

Solar panel and battery size for a 4G camera

A solar 4G camera stays online when its panel puts back each day what the camera uses, and its battery covers the cloudy days in between. Here is how to check both for a site, with a worked example you can redo with your own numbers.

The two numbers that matter

Every solar camera, whatever the brand, comes down to two questions. First, does the panel produce more energy on a normal day than the camera uses in 24 hours? Second, how many days can the battery run the camera when the sky stays grey? A camera that fails the first test drains a little every day and goes offline after a week or two. A camera that fails the second goes offline in the rainy season, which is often when thieves are busiest because the noise of rain covers them.

Catalogue figures do not answer either question on their own. “Up to three months standby” means the camera sitting idle, with no recordings and no live view. “5 W panel” is the output in strong midday sun, with the panel at the right angle and clean. Real use sits between the two.

Step 1: estimate daily energy use

Add up what the camera does in a typical day. The table uses example power figures for a low-power 4G pan-tilt camera; the measured figures for your model are in the datasheet that ships with samples, and you should replace these with them.

Illustrative figures, not measurements of a Solvigil model. Energy (Wh) = power (W) × hours.

Standby is usually the largest share, because it runs all day. That is why a camera that wakes only on motion lasts far longer than one recording around the clock, and why leaving live view open for hours is the fastest way to flatten a battery.

Step 2: check what the panel puts back

A panel’s daily output is roughly its rated watts × peak sun hours × a loss factor. Peak sun hours are the hours of full-strength sun the day adds up to; much of Kenya, Nigeria and Ghana sees four to six on a clear day, fewer in the rainy season and in the cloudier south-west of Nigeria and southern Ghana. Check your site on the Global Solar Atlas. The loss factor covers heat, dust, angle and charging losses; 0.6 to 0.7 is a fair working figure for small camera panels.

• 3 W panel: 3 W × 4 h × 0.65 ≈ 7.8 Wh on a modest day. Close to the 8.6 Wh example, so it only works for a camera with fewer events and little live view.
• 5 W panel: 5 W × 4 h × 0.65 ≈ 13 Wh. Covers the example with a margin to refill the battery after a dull day.

Step 3: size the battery for cloudy days

Battery packs are rated in milliamp-hours. To compare with energy use, convert to watt-hours: mAh × cell voltage ÷ 1,000. Most camera packs, including most of ours, use 3.7 V lithium cells (18650 type), so 7,800 mAh is about 29 Wh. Keep a margin, because cold, age and the cut-off voltage mean you cannot use every last watt-hour; plan on about 80%.

• 7,800 mAh (≈ 29 Wh): about 23 Wh usable, or roughly two and a half days of the example use with no sun.
• 12,000 mAh (≈ 44 Wh): about 35 Wh usable, or about four days. This is why the multi-lens model, with more heads to power, carries the larger pack.

Two to three days of reserve is enough for most farm sites, because even an overcast day usually puts some charge back. Sites with long rainy spells, or cameras covering a busy gate, are where the larger pack and the 5 W panel earn their cost.

Panels and batteries across our range

Factory catalogue figures.

Five settings that save the most energy

1. Use motion or human detection, not continuous recording.The camera sleeps between events.
2. Narrow the detection zone.Leave out a road or a tree that moves in the wind; every false event costs energy and data.
3. Keep clips short.15 to 30 seconds shows what happened.
4. Open live view after an alert,rather than leaving the stream running.
5. Clean the panelafter dusty or dry spells; a film of dust is a steady loss.

Next, read how to install a solar 4G camera so the panel and signal are right on day one, choose a SIM card and data bundle, or compare the six solar 4G camera models. Back to all guides or solar 4G cameras.