Solar Power for Remote CCTV: Sizing Panels and Batteries

A camera pole on a farm, a construction site or a desert road station, with no power for hundreds of metres. Solar is the obvious answer, yet most failed systems we see did not fail because of the sun. They failed because of an undersized panel, a battery cooking inside a metal box, or a charge controller that did not match the battery. This article is about the power system itself: load, panel, battery, controller and cabling.

Start with the real load

Every later figure depends on this one, and any error multiplies. Add up each device from its datasheet and watch three things. Night consumption is higher, because IR illuminators and, on some models, heaters switch on. The 4G router runs around the clock and is often forgotten. And voltage conversion costs energy: a PoE camera on a 12 V system needs a DC-DC converter to PoE voltage, which is never 100% efficient.

Worked example: two cameras and a 4G router

One pole carries two PoE IP cameras averaging 6 W each, a 6 W 4G router, and a PoE converter around 90% efficient.

The 75% covers controller losses, battery round-trip losses, cabling, panel heat and dust. The extra panel capacity is for recovery: on a winter day 200 W gives about 200 × 4 × 0.75 = 600 Wh, a 120 Wh daily surplus to refill the battery after a cloudy or dusty day.

Four peak sun hours is a conservative winter figure for northern Egypt; Upper Egypt does better. For your exact site use free tools such as PVGIS or Global Solar Atlas, and design for the weakest month, not the annual average.

Battery: lithium or lead-acid

LiFePO4 costs more up front, but allows deeper discharge, survives far more cycles and weighs less than half as much as equivalent lead-acid. In the example, one 100 Ah lithium battery replaces two lead-acid units, which matters on a pole. Heat is the real enemy in Egypt: a sealed metal box in summer sun can pass 60 °C inside. Many LiFePO4 datasheets limit charging to roughly 0 to 45 °C, and lead-acid life roughly halves for every 8 to 10 °C above 25 °C.

Tip for installers: keep the battery box in shade, on the north side of the pole or under the panel, ventilated but dust-protected, and avoid dark paint. A few degrees cooler buys years of battery life.

MPPT or PWM controller

A PWM controller ties the panel almost directly to the battery, so the panel runs at battery voltage instead of its maximum power point. That works with 36-cell panels (Vmp around 18 V) on a 12 V battery, but larger high-voltage panels lose much of their output. An MPPT controller tracks the maximum power point and converts excess voltage into charging current. For anything beyond a few tens of watts, we recommend MPPT.

Sizing: 200 W into a 12 V battery is about 200 ÷ 13.5 ≈ 15 A, so a 20 A MPPT controller. With panels in series, keep total open-circuit voltage (Voc) below the controller's maximum PV input with margin, since Voc rises on cold mornings. Set the correct battery profile (a lead-acid profile is wrong for lithium) and use the load output's low-voltage disconnect to protect the battery.

Cabling: voltage drop at 12 V

Panels 10 m from the controller, 15 A, so a 20 m loop. Copper is about 0.0175 Ω per metre per mm².

• 4 mm²: 20 × 0.0175 ÷ 4 ≈ 0.088 Ω, drop ≈ 1.3 V, about 7% of 18 V.
• 6 mm²: about 0.9 V, roughly 5%.
• 10 mm²: about 0.53 V, under 3%.

Use a bigger cable or move the controller closer to the panels, and use UV-resistant solar cable on exposed runs.

Installation and upkeep

Face the panel true south, tilted near the site latitude (about 30° in Cairo), a little steeper if winter output is the priority. Avoid shade all day: partial shade on a few cells can cut output from the whole panel sharply. Dust on desert and farm sites reduces output noticeably, so panel cleaning belongs on the maintenance visit list. Earth the pole, and fit surge protection on any network cable that runs back to a building. A controller with remote battery readings lets you spot decline before the camera goes dark.

How Do Link can help

Within our CCTV solutions we supply low-power Hikvision IP cameras and Uniview IP cameras, 4G routers for off-grid sites, EZVIZ battery cameras for small points, and camera power supplies. Our technical team will help you calculate the load and pick cameras that fit the power budget, with project and wholesale pricing, nationwide delivery and a one-year warranty.

Send us the camera count and site location and we will help you work out the daily load. Contact our team to get started.

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