What Size Solar System Do I Need for 5 kWh per Day?
Five kilowatt-hours is the daily total people often mean by a full-time cabin. This page keeps the load as a single number and shows where rounding up adds a panel.
Full breakdown: what size solar system.
Cabin load lists and worked budgets live on off-grid cabin solar and how many solar panels for a cabin. This page is only the 5 kWh division.
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Array watts at three sun figures
| Sun assumption | Array watts | Plus 20% | Plus 30% | Source |
|---|---|---|---|---|
| 4 peak sun hours | 1,250 W | 1,500 W | 1,625 W | Battle Born |
| 5 peak sun hours | 1,000 W | 1,200 W | 1,300 W | Battle Born |
| Phoenix December, 4.75 | 1,052.6 W | 1,263.2 W | 1,368.4 W | PVWatts; margin Battle Born |
Five thousand watt-hours is divided by 4, 5, and Phoenix December 4.75. The annual 6.54 kWh/m²/day from that same run is listed so it is not used as the winter divisor.
How to size it
The rule is still daily watt-hours ÷ peak sun hours, then 20 to 30 percent more when the array can grow. Nothing on this page assigns the 5,000 Wh to a fridge, a pump, or a cabin square footage.
- 5,000 ÷ 4 = 1,250 W. Then 1,500 W at 20% and 1,625 W at 30%.
- 5,000 ÷ 5 = 1,000 W, then 1,200 W and 1,300 W.
- 5,000 ÷ 4.75 = 1,052.6 W. Margin: 1,263.2 W and 1,368.4 W. December is the low month in the Phoenix run; the annual plane-of-array value is 6.54 kWh/m²/day, which would under-build winter if you used it as the divisor.
- Illustrative panel count at the 30% / 4-hour case: 1,625 ÷ 400 = 4.06, which rounds up to 5 panels. Four modules × 400 W = 1,600 W, and 1,625 − 1,600 = 25 W, so four panels sit just under the 30% target. Five modules × 400 W = 2,000 W. The 5-hour margin (1,300 W) rounds up to 4 panels.
Battery amp-hours from the same watt-hours
| Autonomy | Watt-hours to store | Amp-hours at 12 V | Source |
|---|---|---|---|
| One day | 5,000 Wh | 416.7 Ah | Battle Born battery article (Wh ÷ 12 V) |
| Two days | double | 833.3 Ah | Battle Born: two days off-grid doubles capacity |
At the 12 V of Battle Born's 200 Ah example, 5,000 Wh is 416.7 Ah for one day and 833.3 Ah after you double for two days. The battery bank sizer is the storage step; it does not change the array watts above.
The cabin pages linked above carry weekend and homestead examples. For a flat 5 kWh input, finish in the solar size calculator and run the address in PVWatts.
FAQ
Is 5 kWh a cabin?
A 5 kWh day is a common full-time-cabin question, but this page does not split that energy across appliances. The cabin guides linked at the top use their own load lists. Here the only input is 5,000 Wh.
Why 5 panels instead of 4?
1,625 W is 5,000 Wh ÷ 4 peak sun hours, plus 30%. Divided by an illustrative 400 W module that is 4.06, so the count rounds up to 5. Four × 400 W = 1,600 W, which is 25 W under 1,625 W.
What does Phoenix December do to 5 kWh?
5,000 ÷ 4.75 = 1,052.6 W before margin, or 1,263.2–1,368.4 W after 20 to 30 percent.
What is the 12 V battery for 5 kWh?
5,000 ÷ 12 V = 416.7 Ah for one day, and 833.3 Ah if you double for two days. Take that amp-hour result to the battery bank sizer rather than guessing a cabinet.
Related questions
- What size solar system for 2 kWh per day
- What size solar system for 10 kWh per day
- What size solar system for 1 kWh per day
All of these questions are listed on the topic map.
Sources
- Battle Born Batteries, How to Size Solar Panels for a Deep Cycle Battery System — accessed Oct 2, 2026.
- Battle Born Batteries, How to Size a Deep Cycle Battery Bank — accessed Oct 2, 2026.
- NREL/NLR PVWatts Version 8 API documentation — accessed Oct 2, 2026.
- PVWatts calculator — accessed Oct 2, 2026.