Off-grid solar in Hawaii
In Hawaii's darkest month, December, panels tilted toward the sun get about 5.0 peak sun hours a day, from 5.0 to 5.5 depending on where you are. Sized for that, a typical off-grid home needs about 9 panels and 4 batteries; a cabin, 4 panels and 1 battery. Flat panels, like on a van roof, get 19% less that month.
Answer a few taps in a guide and every page like this shows the numbers for your own setup. Start
Every setup, sized for Hawaii
Each guide's usual answers, with Hawaii's December sun. Tap one to change the answers to yours.
| Setup | Panels | Batteries | About |
|---|---|---|---|
| Off-grid home | 9 × 410 W | 4 | $8,500 – $11,000 |
| Backup for my house | 4 × 410 W | 2 | $9,000 – $11,500 |
| Tiny house | 4 × 410 W | 2 | $5,500 – $7,000 |
| Cabin or shed | 4 × 410 W | 1 | $4,000 – $5,000 |
| RV, bus or skoolie | 4 × 410 W | 2 | $5,500 – $7,000 |
| Van | 4 × 200 W | 3 | $6,000 – $7,500 |
| Just emergencies or camping | 4 × 200 W | Power station | $3,500 – $4,500 |
Van and RV numbers use flat-roof sun (4.1 h). Costs are the gear only.
Sun in Hawaii, month by month
Tilted at latitude Flat. December gets 75% of the sun of the brightest month (6.7 h). Size for December and the rest of the year has spare.
Across Hawaii
Darkest-month sun differs by place. The 2 ZIP areas range from 5.0 hours in the 968xx ZIP area to 5.5 in the 967xx ZIP area. That's 9% more panel output for the same panels.
| State | Darkest month, tilted | Flat |
|---|---|---|
| Hawaii | 5.0 | 4.1 |
| California | 4.1 | 2.6 |
| Oregon | 1.9 | 1.1 |
| Washington | 1.8 | 0.9 |
Common questions
How many solar panels do I need to live off grid in Hawaii?
Sized for Hawaii's darkest month (December, about 5.0 peak sun hours on tilted panels), a typical off-grid home needs about 9 panels (410 W each) and 4 server-rack batteries; a cabin about 4 panels and 1 battery. Your own loads change this; the guides size it for you.
How many peak sun hours does Hawaii get in winter?
About 5.0 a day in December on panels tilted at latitude, and 4.1 on flat panels (NASA POWER, at the state's center of population), ranging from 5.0 in the 968xx ZIP area to 5.5 in the 967xx ZIP area.
Does off-grid solar work in Hawaii in winter?
Yes, if it's sized for December: that month gets about 75% of the sun of the brightest month, so a system sized for December has plenty the rest of the year.
Data: NASA Langley Research Center POWER Project, long-term monthly averages at Hawaii's 2020 Census center of population and at each 3-digit ZIP area. Method and downloads.