What Can a 400W / 800W / 1200W Cabin Solar System Run
The honest answer: it depends on your sun hours, battery size, and how many loads run simultaneously. But rough rules of thumb: a 400W array with 100-200Ah LiFePO4 handles LED lights, phones, laptops, and small radios. An 800W array with 200-300Ah handles those plus a small compressor fridge. A 1,200W array with 300-400Ah handles all that plus a well pump. Above 1,200W you're into full-time cabin territory with Starlink and larger fridges. Below is what each array size actually delivers in daily energy terms.
Solar array sizing conversations get abstract quickly. This guide translates panel wattage into actual cabin capability — what loads work at each array size, what compromises are involved, and what a realistic day of use looks like.
Converting panel wattage to daily energy
Panel wattage is the peak rating. Daily energy production depends on how many "peak sun hours" your location gets. A 400W array in a location with 4.5 peak sun hours produces about 400 × 4.5 = 1,800Wh per day in nominal conditions. Real-world after system losses, closer to 1,500Wh per day.
| Array size | Nominal daily production (4.5 sun hours) | After system losses | Winter production (2.5 sun hours) |
|---|---|---|---|
| 400W | 1,800 Wh | 1,400 Wh | 800 Wh |
| 800W | 3,600 Wh | 2,800 Wh | 1,600 Wh |
| 1,200W | 5,400 Wh | 4,200 Wh | 2,400 Wh |
| 2,000W | 9,000 Wh | 7,000 Wh | 4,000 Wh |
Notice the winter numbers. Cabin systems used year-round should size for winter capability, not summer.
What 400W actually runs
A 400W array with 100-200Ah of LiFePO4 handles:
- LED lighting (10-15 fixtures used a few hours each evening)
- Phone and tablet charging (multiple devices per day)
- Laptop charging (a few hours per day)
- Small radios, GMRS handhelds
- Wi-Fi router if a cellular hotspot is the source
- USB-C charging for various devices
Not comfortably: refrigeration, well pump, extended Wi-Fi with heavier internet use.
This is a bunkhouse, hunt camp, or weekend cabin baseline. Adequate for the loads listed but at the low end.
What 800W actually runs
An 800W array with 200-300Ah adds:
- Everything the 400W system handles
- Small compressor mini fridge (45L, ~400Wh/day)
- Small compressor freezer or larger dual-zone fridge
- Cellular router with cell booster amplifier
- Occasional coffee maker or small kitchen appliance use
- Modest evening TV/entertainment
Not comfortably: well pump on 24/7 pressure switch, Starlink, larger continuous appliances.
This is the standard weekend and family cabin sweet spot. Handles typical loads with reasonable margin.
What 1,200W actually runs
A 1,200W array with 300-400Ah adds:
- Everything the 800W system handles
- Well pump on pressure switch with typical residential-style use
- Larger compressor fridge (65-90L) or chest freezer
- Regular coffee maker and small kitchen appliance use
- Continuous cabin monitoring (cameras, sensors, alerts)
- Modest Starlink use with sleep mode overnight
Not comfortably: full-time Starlink, EV charging, large household appliances (AC, dryer, dishwasher).
This is the entry-level full-time cabin sizing.
What 2,000W and above run
Above 1,200W, you're into full-time cabin territory:
- Everything smaller systems handle
- Full-time Starlink without sleep-mode constraints
- Full-size household fridge
- Small AC/heat pump for limited climate control
- Small workshop tools (drill, table saw for short use)
- Modest EV charging (Level 1 slow charging)
Cabin systems above 2,000W panels typically have 600Ah+ battery banks at 24V or 48V and use inverters with split-phase capability for 240V appliances.
Simultaneous vs. sequential loads
Total daily energy is only part of the picture. Simultaneous loads matter too — the inverter has to supply peak wattage even for brief moments.
- Coffee maker (1,000W) + fridge (200W) + lights (50W) = 1,250W simultaneous. Needs 1,500W+ inverter comfortably.
- Well pump start (3,500W surge) + fridge running + lights = needs 4,000W+ surge capacity.
- Microwave (1,200W) + everything else = 1,500W+ simultaneous.
Cabin systems can trip on peak simultaneous draws even when average daily consumption is well within capacity. Design for peak simultaneous loads, not just totals.
Growing over time
Most cabin owners underestimate initial needs. Systems that grow from 400W to 800W to 1,200W over five years are common as owners realize what they actually want the cabin to do.
Design initial installation for future growth:
- Charge controller sized for eventual array (not just current).
- Wire runs sized for future load levels.
- Battery bank buildable in parallel (matching batteries).
- Panel mounting infrastructure supports additional panels.
Real-world case examples
800W cabin: family weekend cabin in Wisconsin. LED lights, phone/laptop charging, small compressor fridge, occasional coffee maker, cellular router. 300Ah LiFePO4 at 12V. Handles typical weekend use comfortably; occasionally low on the day-after arrival if fridge has been running through a cloudy stretch.
1,200W cabin: full-time cabin in Idaho. Everything above plus 1/2 HP well pump on pressure switch, 65L fridge, Starlink with sleep mode. 400Ah LiFePO4 at 24V. Handles the full cabin infrastructure; needs generator backup for multi-day cloudy stretches in winter.
2,400W cabin: full-time remote-work cabin in Colorado. Above plus full-time Starlink, larger fridge, small mini-split AC for summer, workshop use. 600Ah LiFePO4 at 48V, server-rack style. Genuinely comfortable full-time cabin experience.
Bottom line
Panel wattage translates roughly to daily kWh production (peak sun hours × wattage × system efficiency). 400W handles basic bunkhouse-tier loads. 800W adds refrigeration. 1,200W adds well pump. 2,000W+ handles full-time cabins with Starlink and larger appliances. Size for winter production (not summer averages) if the cabin runs year-round, and design initial installation to support future growth.
Balancing panel wattage and battery capacity
The most common cabin sizing mistake is over-panelling relative to battery. A big panel array charges quickly on sunny days but doesn't help when the battery is empty at 6 AM on the third cloudy day in a row. Balanced growth of both panels (for daily recharging) and batteries (for autonomy) delivers better real-world performance than skewing toward one dimension.
Frequently Asked Questions
What can I run on a 400W solar system?
LED lights (multiple fixtures a few hours per evening), phone and tablet charging, laptop use for a few hours per day, small radios, and USB-C device charging. Not comfortably: refrigeration, well pump, or extended Wi-Fi with heavy internet use. This is the entry cabin baseline.
Can 800W solar run a cabin fridge?
Yes — a small compressor mini fridge (45L, ~400Wh/day) fits within an 800W system with 200-300Ah battery. Larger fridges or dual-zone fridge/freezer combos work but leave less margin for other loads.
What size solar to run a well pump?
A 1/2 HP submersible pump using ~400Wh/day fits within a 1,200W solar array with 300-400Ah battery. The bigger constraint is surge capacity — the inverter needs 4,000W+ surge (or a soft-starter on the pump to reduce surge needs).
Do I need 2,000W of solar for Starlink?
Not quite that much — Starlink adds ~1.5-2 kWh/day. An existing 800W/200Ah cabin adding Starlink typically upsizes to 1,200-1,600W and 300-400Ah. Sleep mode overnight helps significantly.
Should I size for summer or winter solar production?
Whichever season you actually use the cabin most. Full-year cabins should size for December production, which is typically 40-50% of June production. Summer-only cabins can size for summer and accept lower winter capability.