For many people, knowing how much battery life is left on their phone is a big deal. That strong demand for charging has led to all kinds of “hot” products—wireless charging, super-fast charging, and more. But how to charge lithium ion battery correctly is still a question most people get wrong. Let’s break it down.

Do You Need to Fully Drain and Recharge Your Phone?

You’ve probably heard the old advice: let your phone battery run all the way down before charging, and always charge it to 100%. The idea was that this would protect the battery.

That might have been true a long time ago with nickel-cadmium (NiCd) batteries, which had a memory effect. But today’s smartphones use lithium-ion batteries, and the rules are different. If you’re wondering how to charge lithium ion battery properly, the answer is: avoid running it to zero and instead charge it more frequently in smaller amounts.

Plug the Charger First or the Phone First?

In the U.S., household voltage is 120V, but phone chargers output only around 5V. If you’re learning how to charge lithium ion battery safely, the correct way is to plug the charger into the outlet first, and then connect your phone. Doing the reverse can cause a small voltage surge, which may stress your phone over time.

After Charging, Unplug the Phone or the Charger First?

Another part of how to charge lithium ion battery the right way is unplugging order. Always unplug your phone first, then the charger. This avoids reverse current that can slowly wear down your battery.

Extra Tips for Charging Lithium-Ion Batteries

1. Mixing chargers is okay. Most modern chargers have smart chips that adjust voltage automatically.

2. Don’t game or stream while charging. Heat is the real killer of battery life.

3. Avoid thick, heat-trapping cases. Phones need to release heat just like laptops.

 In short, when it comes to how to charge lithium ion battery the right way: charge often in smaller amounts, keep your phone cool, plug into the wall before your phone, and unplug your phone before the charger.