When you’re shopping for a phone or portable charger, you’re bound to come across the term milliamp hours or the abbreviation mAh. Not sure what this means? It’s a simple concept, and figuring out what you need is relatively easy.
What are milliamp hours?
Milliamp hours is a unit that simply measures power over time, abbreviated as mAh. To get a better idea of how this works, we can look at what milliamps are.
A milliamp is a measure of electrical current, specifically one thousandth of an amp. Amps and milliamps measure the strength of an electrical current. Add hours to this and you get a measure of how long this current can flow at that strength.
Take a battery as an example. If that battery can sustain a current output of one milliamp for 1 hour, you could call it a 1 mAh battery. A milliamp is a small amount of power, so this battery would not be very practical.
We pretty much see mAh used in any battery-powered electronic device, from phones to Bluetooth speakers. These devices range from hundreds of milliamp hours to thousands in terms of capacity, but they are all measured the same way.
One thing to note here is that milliamp hours is just a measure of capacity. They do not dictate how fast your charger will charge a given device. This varies across chargers based on a number of factors, such as whether they support fast charging.
Milliamp Hours and Charger Capacity
The average smartphone these days has a battery capacity ranging from 2,000 to 4,000 mAh. These are much bigger batteries compared to older flip phones and smartphones. But as phones have become more advanced, the demand for batteries has increased, reducing overall battery life. This means that portable chargers are more popular than ever.
To be useful, you’ll want a portable charger that has at least as much battery capacity as whatever you want to charge. After all, an old charger with a capacity of 2,000 mAh will not do much for an iPhone 13 Pro Max with a 4,352 mAh battery.
A charger with about the same capacity as your phone or tablet is better than nothing, but in this case, bigger is almost always better. Even if you don’t use the full capacity of your charger, it’s often better to have the extra juice and not need it than to lose it.
That said, needs can vary greatly between people. If you want to charge your smartphone while camping, you’ll want a charger with a higher capacity, as you’ll likely have fewer (if any) opportunities to recharge. Look for something in the neighborhood of 20,000, especially if you’re planning longer trips.
If, on the other hand, you occasionally need to top up a bit at the end of the day, a charger with 10,000 mAh will suffice for your needs.
Is there such a thing as too much capacity?
Charger capacity continues to increase as the batteries in our devices get bigger. With that in mind, is it possible to have a charger with too much capacity for the devices you’re charging?
While there are some downsides to a larger magazine capacity, there aren’t many and none of them are dangerous. Having a charger with many more milliamp hours of capacity than you need will not harm your devices.
Instead, the main disadvantage of a charger with more capacity than you need is the size. More capacity means larger batteries, which sometimes require more space to cool down, so you end up with a much larger charger. This can be inconvenient if you’re carrying a charger on a backcountry hike, but smart packaging can solve this problem.
The other drawback of a larger capacity battery is that it can take longer to recharge. This is often not as bad as you might assume, but if you use a charger on a daily basis, you’ll probably want it to charge fast.
If you’re in a hurry and don’t want to look up your phone’s battery capacity to choose a charger, take a look at our roundup of the best portable phone chargers. While you’re at it, you might want to make sure your wall charger is ready too.