The basic method: plug it in like any other device
A portable charger recharges the same way your phone or laptop does — by plugging a cable into its charging port and connecting the other end to a power outlet or USB port. Most portable chargers come with a USB-C or micro-USB cable in the box. Plug the cable into the port on the charger itself (not the port where you plug in your phone), then plug the other end into a wall outlet using an adapter, or into a USB port on a computer.
The charger will usually show a light or indicator when it is receiving power. Some lights stay on the whole time it is charging; others turn off when the battery is full. Check your charger's manual to understand what the lights mean, since this varies by brand and model.
Charging time depends on the charger's capacity and the power adapter you use. A small portable charger might take 2 to 4 hours with a standard 5-watt adapter, while a larger one could take 8 to 12 hours. Using a higher-wattage adapter (like a 20-watt or 30-watt charger) will speed this up, but only if your portable charger supports fast charging — check the manual to be sure.
Key Takeaways
- Portable chargers plug into a wall outlet or USB port using the cable that came in the box, with the cable connected to the charger itself, not to the phone port.
- Most portable chargers take between 2 and 12 hours to fully recharge, depending on their size and the power adapter you use.
- A higher-wattage adapter will charge your portable charger faster, but only if the charger's manual says it supports fast charging.
- You can charge a portable charger while it is charging your phone, though this slows down both processes.
- Portable chargers last longer if you recharge them before they are completely empty, rather than waiting until the battery is dead.
Understanding the ports and cables on your charger
A portable charger has two different ports, and it is straightforward to confuse them. The input port is where you plug in the cable to recharge the charger itself — this is usually USB-C, micro-USB, or Lightning, depending on the brand. The output ports are where you plug in your phone or other devices — these might be USB-A, USB-C, or Lightning.
If your charger came with a cable, use that cable for recharging. If you lost it or need a replacement, buy a cable that matches the input port on your charger. For example, if the input port is USB-C, buy a USB-C cable. The output ports do not matter for recharging the charger — they only matter when you are charging your phone.
Some newer portable chargers have a USB-C input port that also works as an output port, meaning you can use the same cable to recharge the charger or to charge your phone. Check your manual to see if yours has this feature.
Choosing the right power adapter for faster charging
The power adapter you use affects how fast your portable charger recharges. A standard phone charger is usually 5 watts, and it will work, but a higher-wattage adapter will charge faster. Common wattages are 18 watts, 20 watts, 30 watts, and higher.
Before you buy a higher-wattage adapter, check your portable charger's manual or the label on the back of the charger. It will list the maximum wattage it can accept — often written as "Input: 18W" or similar. Do not use an adapter with a higher wattage than the charger supports, because it can damage the battery.
If your charger supports 18-watt input and you have a 30-watt adapter available, using the 30-watt adapter will not help — the charger will only draw 18 watts. The charger itself controls how much power it takes in, so you cannot overcharge it by using a more powerful adapter, as long as you stay within the charger's rated maximum.
Charging your portable charger while it charges your phone
You can plug your portable charger into a wall outlet to recharge it while you are using it to charge your phone at the same time. This works, but both devices will charge more slowly because the charger is splitting its power between recharging itself and powering your phone.
This is useful in situations where you need your phone charged right away and do not have time to fully recharge the portable charger first. However, if you have the time, it is faster to fully recharge the portable charger first, then use it to charge your phone.
How to know when your portable charger is fully charged
Most portable chargers have LED lights that show the battery level. A full set of lights (usually four or five) means the charger is fully charged. Some chargers have a button you press to see the lights; others show the lights all the time.
A few portable chargers have a screen instead of lights, which will display a percentage or a full-battery symbol. Check your manual to understand what your specific charger's indicator means.
Once the charger is fully charged, unplug it from the wall outlet. Leaving it plugged in after it is full does not damage modern chargers, but it is not necessary and wastes a small amount of electricity.
Keeping your portable charger in good condition
Portable chargers last longer if you recharge them regularly rather than letting them run completely empty. Try to recharge your portable charger when it reaches 20 percent battery, rather than waiting until it dies. This is especially important if you plan to store the charger for a long time.
Store your portable charger in a cool, dry place. Heat damages the battery, so do not leave it in a hot car or in direct sunlight. If you are storing it for months without using it, recharge it every few months to keep the battery healthy.
Avoid dropping your portable charger or exposing it to water, as this can damage the internal battery and the charging circuit. If your charger gets wet, let it dry completely before plugging it in again.
Troubleshooting when your portable charger will not recharge
If your portable charger is not charging, start by checking the cable. Try a different USB cable to see if the problem is the cable itself rather than the charger. Many charging problems are caused by a damaged or worn-out cable.
Next, try a different power outlet or a different adapter. The outlet or adapter might be broken, not the charger. If the charger works with a different outlet or adapter, you have found the problem.
If the charger still will not charge with a different cable and a different outlet, the charger's battery or charging circuit may be damaged. At this point, the charger likely needs to be replaced. Most portable chargers come with a one-year warranty, so check whether yours is still covered.
Frequently Asked Questions
Can I use any USB cable to recharge my portable charger?
No — the cable must match the input port on your charger. If your charger has a USB-C input port, use a USB-C cable. If it has micro-USB, use a micro-USB cable. Using the wrong cable will not work at all.
How long does it take to fully recharge a portable charger?
Most portable chargers take 2 to 12 hours, depending on their size and the power adapter you use. A small charger with a standard 5-watt adapter might take 2 to 4 hours. A large charger with a standard adapter could take 8 to 12 hours. Using a higher-wattage adapter can cut this time in half.
Is it bad to leave my portable charger plugged in overnight?
Modern portable chargers have built-in protection that stops charging once the battery is full, so leaving it plugged in overnight will not damage it. However, it is not necessary and uses a small amount of electricity. Unplugging it when it is full is the better habit.
Why is my portable charger charging slowly?
The most common causes are a damaged cable, a low-power adapter, or a broken outlet. Try a different cable and a different outlet first. If the charger still charges slowly, you may need a higher-wattage adapter — check your charger's manual for the maximum wattage it supports.
Can I charge my portable charger with a solar panel?
Yes, if the solar panel has a USB output port that matches your charger's input port. Solar charging is much slower than wall charging — it might take a full day of sunlight to recharge a portable charger. This works best as a backup option rather than your main charging method.