How Long Does a Power Bank Stay Charged?

Most people who purchase power banks rely on them on a daily basis. But sometimes it takes a long time between charging up the power bank and actually using it. It can be weeks or even several months between two uses of the device. 

One common scenario is that of people who buy power banks for emergency situations. For example, you can get a power bank that has a jump-starter feature, charge it up fully, and then just leave it in the trunk of your car when you need it. But it might happen that you’ll need it after one year.

Will it still be fully charged after such a long time? Or will it be depleted? This is what we’re exploring in this article. 

The Average Depletion Rate For a Fully-charged Power Bank

The fact of the matter is that any battery will lose its charge after a while even if not in use. This is called the self-depletion rate. How long it takes for this to happen depends mostly on the type of battery, its built quality, its age, and the environment it’s being stored in. This holds true for power banks as well, which are nothing else than fancy batteries.

Quick Answer
In general, you can expect a high-quality power bank to hold its full charge for three to six months with no battery loss. The depletion rate can be highly variable depending on the specific make and model of the power bank. It’s important to note that even high-quality power banks can lose charge over time due to self-discharge, although they typically have a slower self-discharge rate compared to lower-quality models.

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Factors That Can Lead to Faster Power Loss

Storage Environment

Power banks are affected by their treatment and the environment they’re exposed to. Storing your device in a car where the temperature constantly changes can affect its charge, while also damaging the device’s lifespan in general. In order to make the most of your portable charger, you should safely store it in a ventilated area with a temperature of around 20°C (68°F). 

Avoid keeping the device in a humid area. Moisture can seep into the batteries, causing rust, and damaging the battery’s condition. 

Usage Style

Not using your power bank for three or more months can impact its performance, and lifespan and result in poor battery life. If you own a power bank that you’ll only use for emergencies, ensure you periodically drain it and charge it back up to prevent the battery from depleting when you need it most. Don’t expect to store it in your car for a year or more and return it to a fully charged device.

Make sure not to drop your portable charger. It contains fragile components and a circuit board that can be easily damaged, thus affecting its battery life.

Battery Type

The type of battery used to build the portable charger is another factor that determines long-term power loss. There are basically two different types of batteries in power banks Lithium-ion (Li-ion) and Lithium-Polymer (Li-Po).

Li-ion batteries are more common when it comes to power banks and they can hold their charge for longer, even when not in use. They can provide more energy, resulting in a quicker charge.

So if you want to get a portable charger that holds its power for the longest amount of time when not used, then make sure it has a Li-ion battery.  But overall, the differences between the two battery types are quite nuanced, and the specific performance will depend on the quality of the battery and how it’s used.

Battery Age

Over time, the performance of batteries (including those in power banks) decreases due to a process known as battery aging. This means that an older power bank may not hold its charge as long as when it is new. Factors contributing to battery aging include temperature, the number of charge cycles, and how the battery is used. For example, frequently discharging it fully can accelerate aging.

Manufacturing Quality

The quality and lifespan of power banks can vary considerably between different brands and models. Before purchasing a new power bank, make sure to do thorough research and invest in a quality product from a reputable manufacturer (Anker, Aukey, Zendure, etc.) to ensure you get a power bank that performs well and lasts longer. If you’re unsure, please check out our buyer’s guide for hints and tips regarding what to look for. 

Ways to Prevent Battery Degradation

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You can actively prevent a power bank’s battery degradation by simply being a responsible owner. First, try to keep the battery power on at least 50 percent. When the power bank reaches below half state, the battery cells are more likely to get damaged. 

If your device contains lithium-ion batteries, partial top-ups can prolong its lifespan. It’s generally best to keep a lithium-ion battery between 20% and 80% charged for optimal longevity, not to constantly top it up. However, if you’re not planning to use the power bank for a while, it’s recommended to store it with around 50% charge.

Getting in the habit of doing this can also help the device retain its charge for a longer period of time, too. Even if you don’t need to use your power bank, it’s best to charge it at least every three months to boost the battery and keep it in proper working order. 

Looking After Your Power Bank’s Battery

You can enhance your power bank’s performance when you use it properly. For example, when charging a smartphone, ensure you disconnect the power bank as soon as it’s fully charged. Keeping it plugged in for longer won’t increase its charge, and cause battery wear.

Modern devices typically have circuitry to prevent overcharging, so keeping a phone connected after it reaches 100% charge should not cause any harm. However, keeping a battery at 100% charge for an extended period can increase wear, so it’s not recommended to leave it charging overnight, for example.

Even if your power bank allows for pass-through charging, pay attention to the heat during its operation. If you notice that the portable charger gets really hot while using pass-through charging, it’s best not to use this feature since heat will reduce the lifespan of the device in the long run. 

Each power bank has a number of charge cycles before the battery performance starts to take a noticeable hit. The average figure for this is 500 cycles. Keep this in mind when using your portable charger. Ideally, top it up to 100% every time, but don’t let it drain to 0% on a regular basis. 

With these facts in mind, we hope you are able to effectively maintain your power bank’s battery so you don’t arrive at a depleted power bank when you need it most.

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