How to Charge Your Phone During a Power Outage (With or Without Electricity)

When the power goes out, your phone is the first thing standing between you and total isolation. It's how you check for emergency alerts, reach family, and figure out when the lights are coming back on. The problem is that most people only think about charging their phone after their battery is already low. Here's how to keep it running, whether you have backup power or none at all.

Why a power bank alone isn't enough

A power bank is the obvious first answer, and it's a good one. But it has a limit. Most hold enough charge for two to four full phone charges, and once it's drained, it's drained. In a storm, a hurricane, or rolling blackouts that stretch into days, a power bank alone runs out before the power comes back.

We tested power banks with built-in solar panels. Here's what actually happens.

Many power banks on the market come with a small solar panel built into one side, marketed as a self-charging solution. We bought several and tested them ourselves rather than going off the packaging.

As power banks, they worked well. As solar chargers, the results were much slower than most people expect. The solar panel built into the side of most solar power banks is small, typically 1 to 2 watts. A 10,000 mAh power bank stores roughly 37 watt-hours of energy. Under real-world conditions, a panel that size may only generate a small fraction of that per day. That math is the reason these units take days, not hours, to meaningfully recharge once depleted.

In our testing, one unit gained less than 10 percent charge after spending a full day in direct sunlight. Results like this depend on panel size, weather, the angle to the sun, the power bank's battery capacity, and the internal electronics, so we're reporting it as our test result rather than a universal claim about every solar power bank on the market.

We also tested power banks that come with a real foldable solar panel attached, which is a step up from the built-in single-panel design. These perform noticeably better at actually recharging from the sun. In our testing, several of these combo units prioritized recharging their own internal battery before delivering meaningful power to a connected device.

Here's what that looked like in practice for the units we tested. With the power bank fully depleted and a dead phone connected, the unit prioritized recharging its internal battery before charging the phone. The phone received little or no charge until the power bank's battery management system had restored a meaningful amount of its capacity. Behavior varies by manufacturer and design, so it's worth checking how a specific model behaves before relying on it during an outage.

Why do we sell the solar panel by itself?

This is the design problem a standalone solar panel avoids. There's no internal battery competing for the incoming charge and no battery management system deciding what gets power first. A dedicated panel in the 15-watt range produces far more usable power than the 1 to 2-watt cell built into most solar power banks, roughly a 15-fold difference in rated output.

Under strong direct sunlight, our portable solar panel can recharge a 10,000 mAh power bank in approximately 5 to 8 hours, depending on sunlight conditions, temperature, panel positioning, and charging efficiency. That's a meaningfully faster path to a usable charge than waiting on a panel built into the side of a combo unit.

While solar charging is typically slower than a wall outlet and may not support fast charging on all devices, it can effectively recharge a depleted smartphone when direct sunlight is available, which is the part that matters most during an extended outage.

Why does a solar panel also last longer than a power bank with one built in?

There's a longevity difference, too, and it comes down to basic battery chemistry. Any device with a built-in battery, including a power bank with a solar panel attached, degrades over time. Batteries lose capacity with every charge cycle, and after a couple of years of regular use, even a well-made power bank holds less charge than it did when it was new. Eventually, it needs to be replaced.

A standalone solar panel doesn't have that problem because it doesn't have a battery to wear out. It's just a panel converting sunlight into electricity. Taken care of, it can last for years, well past the lifespan of any individual power bank you pair it with. You can upgrade your power banks, replace them, or add more over time, and the same solar panel keeps working through it all.

Your light can double as your power bank

Most people don't think to charge their phone from anything other than a power bank or a wall outlet. The Brilliant Wireless Light gives you a third option. In an emergency, it doubles as a power bank and can charge your phone directly.

That matters most when you're trying to manage limited gear during a blackout. One device that both lights the room and charges a phone is more useful than two devices, each doing one job. If your power bank is already drained, the light becomes the backup you didn't know you had.

What an emergency hand-crank radio adds

A hand-crank radio doesn't charge your phone in any meaningful way, but it solves a different problem. When cell towers are down or the signal is unreliable, a radio gives you access to emergency broadcasts and local updates without depending on a network at all. Many models include a small USB port for a trickle charge, useful in a pinch but not a primary charging method. Keep one in your emergency kit alongside your power bank and solar panel, not instead of them.

One thing people get wrong about solar during a blackout

If your home has rooftop solar panels, you might assume they keep your power on during a grid outage. Most homes don't. Rooftop and plug-in solar systems are built as grid supplements, not replacements, and most shut off automatically the moment the grid goes down. That's a safety feature preventing your system from sending electricity back into power lines while crews are working on them, not a malfunction.

Portable solar panels work differently because they're never connected to your home's electrical system in the first place. They charge phones, lights, and power banks directly from sunlight, which is exactly why they keep working when the grid doesn't.

How to stretch the battery you already have

While you're waiting on a charge, a few settings changes can buy you real time. Turn on extreme battery saver or low power mode as soon as you know the power is out, not after the battery drops below 20 percent. Drop your screen brightness to the lowest comfortable level. Turn off Wi-Fi, Bluetooth, and location services if you're not actively using them, since all three quietly drain battery in the background even when you're not touching the phone.

Close background apps you're not using. Put the phone in airplane mode and take it out only when you need to check for messages or make a call. Each saves a small amount of charge. Together, they can stretch a single charge from a few hours to most of a day.

What to charge first when you only have limited power

During an active outage, not everything can charge at once, and the order matters. Charge your emergency radio first, since it's your only source of information if cell towers go down. Phones come next, because communication with family and emergency services matters more than anything else once you can receive alerts. Wireless lights come after that, followed by secondary devices and power banks. Whenever the grid comes back on, even briefly, or whenever the sun is out, charge everything you can in that order rather than waiting for a single device to reach full charge.

Building this into your blackout plan

Charging your phone is one piece of a bigger picture. If you haven't put together a full blackout plan for your household, it's worth doing before the next outage, not during it. Our Blackout Preparedness Guide walks through everything else you need, including how many lights your household actually needs, food safety without refrigeration, and the mistakes that turn a manageable outage into a stressful one.