Why are wireless headphones only partially charged at the factory?

Now that many headphones are wireless, they have become more portable than ever. You can now listen to your favorite tunes on the go without dealing with cords that can get tangled or caught on something. However, since wireless headphones run on batteries, you might be wondering if you can use them right out of the box.

Most wireless headphones come charged. They run on built-in lithium-ion rechargeable batteries. However, don’t expect the charge to be 100%. According to the manufacturer’s recommendations, you still need to charge your headphones as soon as you unbox them. This article will shed more light on why wireless headphones are only partially charged at the factory.

Like with any new gadget, the first thing you want to do with a new pair of wireless headphones is to use them as soon as you take them out of the box. Unfortunately, you’ll have to anxiously wait a little longer. Even if you can turn the headphones on, they will usually be only 20–50% charged. Charging could take hours, so why don’t manufacturers make it a practice to fully charge the headphones before packing them?

Charging the Batteries Takes Up Production Time

The batteries in headphones receive a partial charge during the manufacturing and testing phases, which allows the manufacturer to test if the battery and device work. However, there may not be enough time to fully charge the batteries before making it to the packaging stage.

If the manufacturers were to fully charge the headphones before packaging them, it would take more time in the production line. Taking up more time would lead to less output.

The only way to mitigate the lower output would be to increase the workforce and equipment, which would drive production costs up. This would ultimately lead to more expensive headphones. It seems a little convoluted, but every detail in the manufacturing process can have a noticeable effect.

Batteries Self-Discharge

Even if the manufacturers invested in fully charging the headphones at the factory, you still wouldn’t end up with a fully charged device after purchasing it. Batteries self-discharge even when the device they power is off.

Lithium-ion batteries have a self-discharge rate of 1.5–2% per month. The discharge rate increases as temperatures rise. There’s also the fact that a battery with a charge close to 100% will self-discharge more rapidly than one with a charge of 40%.

Headphones can sit on a store shelf for months, so even if they were fully charged at the factory, whoever buys them would still need to recharge the headphones after unboxing them. This would negate any benefit of fully charging the headphones at the factory.

A Partial Charge Puts Less Strain on the Battery

A fully charged battery is prone to more strain than a partially charged battery, and not just because it self-discharges more rapidly. A fully charged battery works harder to contain its energy than one that is only partially charged. For this reason, keeping a battery at full charge weakens it and shortens its lifespan. Lithium-ion battery manufacturers recommend keeping the battery level at 40% if you plan on storing them. It’s crucial to make sure they have some charge—if they lose their charge completely, they could later become unchargeable.