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Solar Chicken Coop Calculator

Enter your flock size and equipment — get a complete 12V solar system: panels, battery Ah, charge controller, and winter vs summer usage.

Flock & equipment
birds
Location & cost
$/kWh
12V solar system for your chicken coop
1 × 100W panel + 62 Ah battery
Est. coop size40 sq ft
Lighting load25 W
Winter daily usage0.18 kWh/day
Summer daily usage0.06 kWh/day
Sizing seasonwinter (higher load)
Battery bank (12V, 2-day)62 Ah
Charge controller11A MPPT
Extra eggs (vs no light)+15 eggs/week
Annual electricity value$5.37/yr
Est. system cost$650
vs grid extensionSolar cheaper upfront
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How to Use This Calculator

Enter your flock size and equipment

Enter your number of chickens — the calculator estimates coop square footage at 4 sq ft per bird and sizes lighting accordingly (25W LED per 100 sq ft). Then toggle each piece of equipment you have or plan to install. The heated waterer is the critical input for cold climates: it's 100W running continuously in freezing weather and often dominates the entire system load in winter.

Understand the seasonal difference

Chicken coop solar has a sharp seasonal difference. In winter, supplemental lighting runs 4–5 hours per day (to top up short natural daylight to 14 hours), and a heated waterer runs all day — this is your high-consumption season. In summer, lighting needs drop to zero and the heated waterer turns off, leaving only the automatic door, ventilation fan, and fence charger. The calculator sizes your system for the worst season.

Why 12V?

Chicken coops typically use 12V systems because loads are small and 12V components (panels, batteries, charge controllers) are widely available, affordable, and simple to wire. A standard 12V 100Ah lead-acid battery costs $100–150 and is easy to find at farm stores. For larger flocks with heated waterers, you may step up to a 24V system for efficiency.

The Formula

Coop sq ft = Chickens × 4 sq ft/bird Lighting Watts = CEILING(sq ft / 100) × 25W LED Winter Daily Wh = (Lights × 5 hrs) + (Waterer × 24 hrs) + (Door × 12 hrs) + (Fan × 8 hrs) + (Fence × 24 hrs) Summer Daily Wh = (Door × 12 hrs) + (Fan × 16 hrs) + (Fence × 24 hrs) System Watts = Worst Daily Wh ÷ 1000 ÷ Peak Sun Hours ÷ 0.80 Panels = System Watts ÷ 100W (round up) Battery Ah (12V) = Worst Daily Wh × 2 days ÷ (12V × 0.50 DoD) Charge Controller Amps = Panels × 100W × 1.25 ÷ 12V

Battery is sized for 2 days of autonomy at 50% DoD (lead-acid standard). Using 50% DoD rather than 80% is intentional — lead-acid batteries last significantly longer when not deeply discharged, and coop systems typically use economical lead-acid. For LiFePO4, you can reduce battery size by 40% using 80% DoD.

Example

Tom — 25 chickens in Denver with winter heating

Tom has 25 laying hens in Denver. He wants an automatic door opener, a heated waterer for winter, supplemental lighting to keep eggs coming through winter, a ventilation fan, and a fence charger for predator control. He pays $0.13/kWh.

Chickens25 birds (~100 sq ft coop)
EquipmentDoor, waterer, lights, fan, fence
LocationDenver, CO (5.5 PSH)
Rate$0.13/kWh

Result

Winter daily usage~2.7 kWh/day
Summer daily usage~0.25 kWh/day
Panels needed5 × 100W panels
Battery bank (12V)900 Ah (2 days, 50% DoD)
Charge controller52A MPPT
Extra eggs/week+37 eggs/week in winter
Est. system cost~$2,000

The heated waterer completely dominates winter consumption — running 100W for 24 hours is 2.4 kWh/day by itself. Tom's 5 panels handle the winter worst-case, and in summer the system produces massive excess (only 0.25 kWh/day needed). The extra egg production from supplemental lighting — roughly 37 more eggs per week through winter — has real value. At $3/dozen, that's over $450/year in additional egg production.

FAQ

A basic coop with just an automatic door and LED light needs only 50–100W of panels and a 50–100Ah battery. Adding a heated waterer changes everything — it draws 100W continuously in winter, requiring 200–400W of panels just for the waterer alone. A typical medium flock setup (25 birds, all equipment) needs 400–600W of panels and 200–600Ah of 12V battery. Always check whether your climate requires a heated waterer before buying equipment.
Yes — this is one of the most proven interventions in poultry farming. Hens need approximately 14–16 hours of light per day to maintain full egg production. In winter, natural daylight drops to 9–10 hours in most US locations, causing hens to reduce or stop laying. Adding supplemental LED lighting to reach 14 hours per day can boost winter egg production by 25–40%. The light doesn't need to be bright — 25W LED per 100 sq ft of coop space is sufficient. Use a timer or light sensor to automate it.
Technically yes, but it's not recommended. Car batteries (SLI — starting, lighting, ignition) are designed for short, high-current bursts, not sustained discharge. Repeatedly discharging a car battery to 50% will damage it within months. Use a deep-cycle lead-acid battery instead — AGM (absorbed glass mat) or flooded deep-cycle. They're designed for repeated discharge/recharge cycles and cost $100–180 for 100Ah. For a cleaner, longer-lasting option, LiFePO4 batteries are increasingly affordable and can handle 80% DoD for 2,000+ cycles.
In winter with a heated waterer, you need significantly more panels than you'd expect. The waterer alone (100W × 24 hrs = 2.4 kWh/day) requires roughly 200–300W of panels in a sunny location (5 PSH) or 400W+ in cloudy northern regions (3.5 PSH). Without a heated waterer, winter sizing is much more modest — a single 100W panel typically handles lights, door, fan, and fence charger through winter in most US locations.
It depends on the distance. Running a buried electrical line to a coop typically costs $500–1,500 for short runs (50-100 ft) and $2,500–10,000 for longer runs requiring trenching. A complete solar system for a small coop (100W panel + battery + controller) costs $200–600. For most backyard coops within 100 ft of the house, grid extension may actually be cheaper. Solar becomes clearly better for remote coops 200+ ft away or where trenching is difficult. The added benefit: solar works anywhere, no permits usually required for small systems, and it's expandable.

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