Once the core system is sized, the practical question becomes: what can you actually run, and what does each appliance cost you in terms of battery drain? Here's a working reference for common cabin appliances.
Appliance Wattage Reference
| Appliance | Typical Running Watts | Startup Surge |
|---|---|---|
| LED light fixture | 5-15W | None significant |
| Laptop charger | 45-65W | None significant |
| Small compressor fridge | 60-100W avg (cycles on/off) | 2-3x running watts |
| 12V water pump | 40-80W | 1.5-2x running watts |
| Well pump (120V) | 750-1,500W | 2-3x running watts |
| Microwave | 600-1,200W | None significant |
| Coffee maker | 600-1,000W | None significant |
| WiFi router | 10-20W | None significant |
These are typical ranges — check your specific appliance's nameplate rating for exact figures, since efficiency varies significantly between models, especially for fridges and pumps.
The Fridge Question
Fridges are usually the single biggest continuous draw in a cabin, since they cycle on and off around the clock rather than running only when someone's actively using something. A small, efficient 12V or low-wattage compressor fridge designed for RV/off-grid use draws meaningfully less than a standard household fridge, and is worth the swap if you're building a cabin system from scratch specifically for solar.
Well Pumps Need Special Attention
Well pumps draw significant startup surge and run on 120V AC, meaning they need a properly sized inverter (see our inverter sizing guide) and a battery bank that can handle the surge without dropping voltage. If your cabin relies on a well pump, size the inverter and battery bank around that specific load first, then add everything else.
Calculating Your Total Load
Add up the daily watt-hours (watts × hours used) for everything on your appliance list, using our full sizing guide to translate that total into panel wattage and battery capacity. Pay particular attention to anything that runs continuously (fridges) versus anything used briefly (power tools, coffee makers) — continuous loads matter far more for battery sizing than occasional high-wattage spikes, which mostly just need to be covered by inverter capacity.
Reducing Load Without Reducing Comfort
- Switch to LED lighting throughout if you haven't already — the wattage difference versus older bulb types is substantial.
- Choose a dedicated 12V or DC-native appliance where available (fans, some lighting, some pumps) to skip the small but real conversion loss of running everything through an inverter.
- Stagger high-draw appliance use rather than running everything simultaneously, which reduces your peak inverter sizing requirement even if it doesn't change total daily watt-hours.
Appliance Efficiency Ratings Matter
Not all appliances of similar function draw similar power — a fridge specifically designed for RV/off-grid use, or one with a strong efficiency rating, can draw meaningfully less than a bargain unit of similar size. When building a cabin system from scratch, checking efficiency specs before buying appliances is often a more cost-effective way to reduce your power budget than oversizing your solar system to accommodate an inefficient appliance choice.
Building a Load-Shedding Priority List
Even a well-sized system occasionally faces a stretch of unusually low production — several cloudy days in a row, for instance. Having a mental (or written) priority list of what to cut back on first — skip the coffee maker, delay laundry-adjacent tasks if applicable, reduce non-essential lighting — before things get critical is more useful than discovering your priorities in the moment when the battery's already low. This is a small planning step that meaningfully reduces stress during the rare stretch when a cabin system is genuinely tested by weather.
Standby/Phantom Loads Add Up
Many devices draw a small amount of power even when "off" but still plugged in — chargers, some electronics with standby modes, certain appliances with digital displays. Individually small, these phantom loads can add up to a meaningful chunk of daily consumption on a cabin system where every watt-hour is coming from a finite battery bank rather than an unlimited grid connection. A simple power strip with a physical switch, used to fully cut power to non-essential devices when not in active use, is a low-cost way to eliminate this drain.
Seasonal Appliance Adjustments
Some cabin owners deliberately adjust appliance use by season — running a space heater backup in shoulder seasons when solar production is lower, or using more power-hungry conveniences freely in summer when production is abundant. This kind of seasonal awareness, treating solar output as a variable resource rather than a fixed utility-like supply, is a mindset shift that helps get more practical value out of a correctly-sized system without needing to oversize it purely to cover every season equally.
Testing New Appliances Before Full Reliance
Before fully committing to running a new appliance regularly on your cabin solar system, test it for a few days while monitoring battery state of charge, to confirm your estimated wattage and usage hours match reality. Nameplate ratings on appliances are sometimes optimistic compared to real-world draw, and actual usage patterns (how long something really runs per day) often differ from initial assumptions, making a short real-world test a valuable check before assuming your sizing calculation holds for a genuinely new load.
A Reasonable Starting Appliance List
For anyone building a cabin power plan from scratch without an existing appliance list to reference, a reasonable starting point covers LED lighting throughout, phone and laptop charging, a WiFi router if desired, and a small efficient fridge if the cabin sees regular use — covering the large majority of what most cabin visits actually need before considering anything more specialized like power tools or a well pump.
Revisit This List Periodically
Appliance loads change as a cabin evolves — new devices, replaced appliances, changing usage patterns among the people using the space. Revisiting your appliance wattage list periodically, rather than treating it as a one-time exercise, keeps your understanding of your system's actual demands current as things change over the years.
Appliances Are the Reason You're Doing This
It's easy to get absorbed in panels, batteries, and wiring diagrams and lose sight of the actual point: running the things that make a cabin comfortable and useful. Keep your appliance list and actual usage patterns as the anchor for every sizing decision throughout this guide, rather than sizing components in the abstract and hoping they happen to match how you actually want to use the space.