Rank essential functions before choosing a battery, then check energy, output compatibility, and a fallback without power.
Begin with what fails first
Some households need light and phone charging most urgently. Others depend on powered medical equipment or safe medication storage. The right plan follows those needs rather than the size of the largest available battery.
Separate inconvenience from a safety-critical interruption. Trying to operate every appliance can consume energy intended for the devices that matter most.
Address medical and movement needs first
Ask a medically necessary device’s supplier and your care team about an individual outage plan. Required voltage and power are only part of the question: transfer time, internal battery life, storage conditions, assistance, and an alternative location may also matter.
Check lighting along the path from a bedroom to the exit. Keep a working battery light accessible. Shared building equipment such as elevators and entry systems requires a management plan; a personal power bank cannot restore it.
Write operating hours beside each load
Power multiplied by time gives energy. The following is a worked example, not a product recommendation or measurement.
| Example load | Assumed use | Energy |
|---|---|---|
| Small light | 5 W for 5 hours | 25 Wh |
| Communication device | 10 W for 3 hours | 30 Wh |
| Small device | 20 W for 2 hours | 40 Wh |
| Total delivered to loads | 95 Wh |
If an illustrative usable-energy fraction were 80%, the nominal requirement would be 95 ÷ 0.8, or about 119 Wh. Actual selection must also consider startup demands, continuous output, standby use, and compatibility. The assumed efficiency is not a guarantee.
Alongside each device, write a fallback: a separate flashlight, shorter operating time, a paper contact card, or a safe alternative location.
Treat refrigerators and internet access separately
A refrigerator cycles and may have a substantial startup load. One label number multiplied by hours does not reliably predict runtime. Check both appliance requirements and the power source’s continuous and surge limits.
If refrigeration cannot be maintained, keep doors closed and follow food-specific temperature and time guidance. Do not taste uncertain food to test it.
Powering a router does not guarantee internet service if the modem, building equipment, or provider infrastructure is unavailable. Preserve offline contacts and another way to receive available official information.
Keep fuel-powered equipment out of the home
Never run a fuel-powered generator indoors, in a garage, or on an enclosed balcony. It belongs outdoors at least 20 feet from building openings, with exhaust directed away. Opening a window does not make indoor operation safe.
Do not plug a generator into a wall outlet to energize household wiring. A building connection requires appropriate installed equipment and a qualified professional.
Common questions
Is a UPS equivalent to a large battery? Switching behavior, waveform, output, and supported loads can differ.
Will one large device cover everyone? Consider failure of that device and the difficulty of moving it. Independent small lights can simplify the plan.
Do this today
- Rank three essential functions.
- Record real device specifications and required hours.
- Identify fallbacks without electricity.
- Show family members where lights and contact cards are kept.
References: Ready.gov power outage guidance and FoodSafety.gov emergency food safety.