Chapter 18 · Your home as a shelter
18.6 Light and power inside the shelter
The centerpiece is a portable power station (lithium battery with AC outlets, USB ports, and solar input) plus a folding solar panel. It makes no noise, produces no fumes, and can be used indoors. The general list for light and power is in chapter 2; multi-week blackouts are in chapter 23.
How to calculate how much battery you need
- Read the watts of each device (on the label or the charger).
- Multiply by the hours per day you will use it: that is watt-hours (Wh).
- Add it all up and compare it to the station's capacity. Count only about 80% of the rated capacity as usable, because of conversion losses (approximate; varies by model).
| Device (example) | Watts (check yours) | Hours per day | Wh per day |
|---|---|---|---|
| Box fan with filter | 50 | 8 | 400 |
| Household phones (one full charge each) | — | — | ≈ 60 |
| 2 LED lamps | 5 each | 5 | 50 |
| Radio | 2 | 6 | 12 |
| Total | ≈ 520 Wh |
With this example, a 1,000 Wh station lasts a little over a day and a half without sun. The solar panel recharges during the day, but it produces considerably less than its rated power: it depends on the time of day, clouds, and angle. If anyone uses electric medical equipment (CPAP, oxygen concentrator), calculate its consumption first and talk to their doctor about backup.
