To size solar power for a CCTV site, start from the daily energy the cameras, recorder and radio actually draw, then divide by what the array can realistically deliver in the worst month, and size the battery for the longest expected run of cloudy days. Most CCTV solar systems fail not because the panel is too small, but because the load was estimated from datasheet labels instead of measured draw.
Step 1: Build a real load audit
Datasheet “max power” is a peak figure, not a continuous one. For a typical 4-camera site, these are the values worth planning with:
| Device | Typical draw | Hours/day | Daily Wh |
|---|---|---|---|
| Bullet camera (IR on at night) | 5-9 W | 24 | 120-216 |
| PTZ camera (moving) | 15-40 W | 4-6 active | 60-240 |
| NVR / recorder | 10-25 W | 24 | 240-600 |
| 4G router or radio link | 3-10 W | 24 | 72-240 |
| PoE switch | 8-20 W | 24 | 192-480 |
Add an inverter or PoE conversion loss of 8-15 percent on top. A four-camera site with a recorder and 4G link commonly lands between 700 and 1,400 Wh per day. That single number drives everything downstream.
Step 2: Convert to array size using worst-month yield
Do not size with annual average sun hours. Use the lowest monthly value for your site and tilt, because the system must survive February, not the yearly mean.
Array Wp = (daily Wh x 1.25) / (worst-month peak sun hours x system efficiency)
System efficiency of 0.7 is realistic once you account for dust, high cell temperature, controller loss and cabling. A 1,000 Wh/day load in a location with 4.0 peak sun hours in the worst month needs roughly:
(1000 x 1.25) / (4.0 x 0.7) = 446 Wp
Round up, and add 15-20 percent if the panels cannot be tilted at the optimum angle or will be mounted flat on a pole cap.
Step 3: Size the battery for cloudy days, not for output
Battery capacity is set by autonomy, the number of consecutive days the site must run without meaningful sun. For security sites in monsoon or harmattan conditions, 3-5 days is normal; 2 days is only acceptable where someone can visit quickly.
Battery Wh = (daily Wh x autonomy days) / usable depth of discharge
At 1,000 Wh/day, 3 days autonomy and 80 percent usable DoD on LiFePO4: 3,000 / 0.8 = 3,750 Wh. With gel batteries limited to 50 percent DoD, the same site needs 6,000 Wh — which is why lithium usually wins on remote sites once you compare installed weight and enclosure size, not just price per kWh.
Step 4: Match controller and voltage
Use an MPPT controller at 1.25 times the array’s short-circuit current, and keep the array voltage high enough that the controller still charges when cells are hot. A 4-panel series string feeding a 24 V battery bank is a common, robust arrangement; 12 V systems struggle to carry the cable run to a pole-mounted array.
Common mistakes that kill CCTV solar systems
- Designing on average sun hours instead of the worst month
- Ignoring night IR current, which roughly doubles camera draw after dark
- Leaving no surge headroom for heater or wiper options
- Mounting panels flat on a pole cap in a dusty region, then never cleaning them
- Using a PWM controller with a high-voltage array, wasting 20-30 percent of harvest
FAQ
How many watts of solar do I need for one CCTV camera?
A single 24/7 camera drawing 6 W needs about 145 Wh/day. With a 1.25 design margin and 4 peak sun hours, that is roughly 65 Wp of array plus a battery sized for the local cloudy-day run — practical kits start around 100 W.
Can I run a CCTV camera directly from a solar panel without a battery?
No. The camera needs stable voltage through the night and through cloud, and the panel output collapses with passing shade. A battery and controller are mandatory; the panel only replaces the energy the battery delivers.
How long will a 100Ah battery run a CCTV system?
At 80 percent usable capacity on a 12.8 V LiFePO4 pack, about 1,000 Wh is available. That runs a 700 Wh/day site for roughly 1.4 days — enough for a single cloudy day, not for a monsoon run.
If you send us the camera models, the recorder and the site’s worst-month sun hours, we will return a sized panel, battery and controller combination. Request a sizing proposal, or see CCTV solar kits.