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Small Cabin Solar Calculator
Start with what you use each day, not a kit wattage. This small-cabin example totals 1,650 Wh per day before system losses. Open the example in the calculator, replace the assumptions, then choose your location.
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Illustrative inputs · 24 V nominal battery · 2 days of autonomy · LiFePO4 assumption. No signup required.
Example daily energy budget
| Appliance | Running W | Hours/day | Quantity | Wh/day |
|---|---|---|---|---|
| Cabin refrigerator (example) | 150 | 8 | 1 | 1200 |
| LED bulb | 10 | 4 | 4 | 160 |
| Laptop | 65 | 4 | 1 | 260 |
| Small water pump | 60 | 0.5 | 1 | 30 |
| Daily energy before system losses | 1650 Wh | |||
What this example includes
Four LED bulbs, a modest refrigerator, one laptop and a small water pump. The refrigerator's eight hours represent equivalent compressor run time, not eight hours plugged in. Measure your refrigerator over several days or use its annual energy label. This budget excludes electric space heating, water heating, cooking, air conditioning and power tools.
Choose the season you need to cover
An annual average can hide a winter shortfall. At an illustrative 4.5 peak sun hours, the energy-only panel target is 1,650 ÷ 4.5 × 1.3 = 477 W. At 3 hours it is 715 W, before rounding to panel sizes. These are assumed sun hours, not a forecast for your cabin. Shade, snow and weather may reduce output further.
What two days of battery autonomy means
Two days without useful solar require 3,300 Wh delivered to these loads. With the calculator's 90% depth-of-discharge and 90% inverter-efficiency assumptions, the unrounded battery target is 4,074 Wh. At the example's 24 V nominal voltage, rounding to 50 Ah steps yields 200 Ah, or 4.8 kWh nominal. A 25.6 V battery's nameplate energy differs; compare its actual usable energy and BMS limits.
Before choosing equipment
The 24 V setting is an editable example, not a wiring instruction. Refrigerator and pump starting current can exceed their running power. The calculator does not model this surge. Check inverter surge duration, battery discharge limits, controller input limits, cold-weather panel voltage, conductor sizing and protection with an installer before buying. Plan for backup power during prolonged poor weather.
How equipment suggestions work
Run the calculator with your own inputs to see any available equipment candidates. Candidates are screened by the specifications stated alongside them. They are not a complete compatible kit, and prices are shown by the retailer. We do not claim to have installed or field-tested these example systems.
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Prepared by BestChain Inc. Updated September 22, 2026. About our calculation limits.