How to keep a fridge running during a blackout

Why fridges need special planning

• The compressor does not run continuously. A typical household fridge runs its compressor 30–50% of the time in normal conditions. That means average consumption is much lower than the nameplate wattage suggests — but the startup peak must still be handled by the station's inverter.
• Startup (surge) watts can be 2–5× running watts. When the compressor starts, it draws a large current spike lasting a fraction of a second. A station's inverter must exceed this peak or the compressor will not start and may trigger a protection cutoff.
• Temperature matters. A fridge in a hot kitchen or a full freezer after a blackout works harder. Add 20–30% to consumption estimates in summer or if the ambient temperature is above 25°C.
• Full vs empty. A full fridge retains cold longer and cycles less. An empty fridge loses temperature quickly and the compressor runs more to compensate.
• Modern inverter compressors are significantly more efficient than older fixed-speed compressors. A 2020+ A+++ unit may average 60–80W where an older model averages 150–200W for the same volume.

Fridge types and real consumption figures

Running watts are averages during the compressor-on phase. Average watts over 24h are what determines the Wh you need from your station. Surge watts are the peak that your inverter must handle at startup.

All figures are estimates. Actual consumption depends on efficiency class, ambient temperature, load, door opening frequency and age of the unit. Use the label on the back of the appliance for the most accurate wattage.

Startup surge: the number most people miss

• What it is: when a compressor motor starts, it briefly draws 2–5× its normal running current. This lasts 0.1–0.5 seconds but is enough to trip protection circuits on undersized inverters.
• Why it matters: a station rated at 1,000W continuous might have a 2,000W surge rating. A fridge compressor with a 1,500W startup peak will start fine. A 2,500W startup peak may trip the station.
• Inverter compressors (modern A+++ units) have much lower surge because the motor speed ramps up gradually. A variable-speed compressor may only need 1.5–2× running watts to start. This is one reason modern fridges are both more efficient and easier to back up.
• Fixed-speed compressors (common in older units and cheap models) start at full speed instantly and draw the highest surge. Always confirm surge watts for any fridge over 5 years old.
• How to find surge watts: check the appliance data plate (usually on the back or inside the door), the manufacturer's technical sheet, or contact the brand. If unavailable, use 3× running watts as a conservative estimate for fixed-speed, 2× for inverter compressors.

How long will each station keep a fridge running?

Calculated at average consumption with a 15% efficiency loss from the inverter. Based on a 50% duty cycle (compressor on half the time), which is typical at 20°C ambient.

Add router (20W), lights (30W) and phone charging (20W) and reduce runtimes by approximately 30%. With a 200W solar panel in good sun conditions, runtimes extend significantly or become indefinite.

12V and 24V compressor fridges: the efficient choice

• 12V/24V DC compressor fridges (using Secop or Danfoss compressors) are the most efficient option for portable power use. They run directly from DC, avoiding the inverter efficiency loss that AC fridges incur.
• Typical brands and models:
  • Dometic CFX3 series (25L to 100L) — industry benchmark for efficiency and build quality. The 35L averages 12–18Wh/day; the 75L dual-zone averages 25–40Wh/day.
  • Engel MT/MD series — Australian-made, extremely durable, popular for overlanding and marine use. Slightly higher consumption than Dometic but exceptional reliability.
  • ARB Elements series — dual-zone option with robust build for off-road use.
  • BougeRV / Alpicool / Iceco — Chinese-made budget options with Secop compressors. Good value for occasional use; variable build quality.
  • Brass Monkey — New Zealand brand, well-regarded for campervans and travel.
• Why DC fridges are better for portable power: a 12V fridge drawing 40W DC uses 40W from your station. A household fridge drawing 40W AC actually pulls 46–48W from the station after inverter losses. Over 24h that difference is small, but DC fridges also have lower surge and more predictable consumption.
• Dual-zone fridges (one compartment fridge, one freezer) allow independent temperature control. The freezer section draws more power; if you only need cooling, set both zones to fridge temperature to reduce consumption.

What actually happens to food during a blackout

• A full, closed fridge maintains safe temperature (<4°C) for 4–6 hours without power in a normal kitchen environment. A full freezer can maintain safe temperature (<0°C) for 24–48 hours if the door is not opened.
• Key rule: keep the door closed. Every opening replaces cold air with warm air and forces the compressor to work harder when power returns.
• Food safety thresholds: bacteria multiply rapidly above 4°C. Meat, dairy and prepared foods become unsafe after 2–4 hours above 4°C. Hard cheeses, whole vegetables and condiments tolerate longer interruptions.
• Frozen food: if food still contains ice crystals when power returns, it is safe to refreeze. If it has fully thawed and been above 4°C for more than 2 hours, cook it or discard it.
• The practical conclusion: for outages under 4 hours, you may not need to power the fridge at all. For outages over 4–6 hours, backup power protects your food and avoids waste costing €100–€400+ in spoilage.

Sizing guide: fridge only vs fridge + essentials

Solar + fridge: the long-term answer

• A single 200W solar panel produces 600–1,000Wh on a good day in southern Europe (5–6 peak sun hours). A standard household fridge-freezer combo uses 1,200–2,000Wh per day. One panel covers 30–80% of fridge consumption for free.
• Two 200W panels in good conditions can cover the entire fridge load and leave capacity for router, lights and phone charging. An Anker SOLIX F2000 with two panels effectively becomes a self-sustaining home backup system during daylight hours.
• For campervans and off-grid use, a 12V compressor fridge + one 100–200W panel is the standard self-sufficient setup. The fridge uses 25–40Wh/day average; even a modest panel in partial shade produces significantly more.
• Cloudy days and winter: in northern Europe in December, expect 1–2 peak sun hours per day. A 200W panel may produce only 200–400Wh. Plan accordingly or increase panel capacity.
• Practical tip: pre-cool the fridge to below 2°C before an anticipated outage. The thermal mass of cold food acts as a buffer and the compressor runs less, extending your battery runtime.

Common mistakes when backing up a fridge

How to read your fridge's data plate

• Where to find it: inside the door frame, on the back of the unit, or sometimes on the side wall inside the fridge compartment.
• Rated power (W): this is the compressor running wattage — what it draws when the compressor is actively cooling. Not the 24h average.
• Annual energy consumption (kWh/year): from the EU energy label. Divide by 365 to get average daily Wh. Divide by 24 to get average watts over 24h. This is the most accurate figure for sizing.
• Example: a fridge rated at 180W with an EU label showing 250kWh/year uses an average of 685Wh/day = 28.5W average. Despite having a 180W rated compressor, it only averages 28.5W because it cycles on and off.
• Startup surge is rarely printed on the label. For modern inverter compressors, use 2–2.5× rated power as a safe estimate. For older fixed-speed units, use 3–4×.

Technical notes before buying

• Always confirm the station's surge (peak) watts, not just continuous output. A station with 2,000W continuous and 4,000W surge handles most household fridges comfortably.
• For American fridges and large combos above 400L, request a manual confirmation — these often have ice makers and fans that add variable loads.
• If adding solar, check the station's maximum solar input (MPPT watts). Some stations cap at 400W, others accept 1,500W+. More solar input means faster recharge and longer effective autonomy.
• A fridge backup is one of the highest-value uses of a portable station. Food spoilage in a family-sized fridge can represent €200–€500+ — often more than the station's annual depreciation cost.