The drawbacks of fast chargers

There is a lot of talk about fast chargers today and suppliers are bragging about their new fresh chargers that will give your phone a charged battery in no time. But what they rarely say is that fast charging has its drawbacks.

How charging works – explained in the simplest possible way

A battery has a negative and a positive side. In a fully charged battery you have, on the negative side, lots of electrons. On the plus side, you have fewer electrons. The electrons want to jump to the positive side. On the journey between the negative and the positive side, the electrons can give power to the units that are in their path. When all the electrons have moved to the positive side, the battery has no more power. Then electricity is used to move the electrons back to the negative side again, so you recharge the battery.

What fast chargers does, is that they move the electrons back from the positive side to the negative side, much faster than a regular charger does.

And so far, everything sounds great. For who does not want to be able to charge their phone or tablet as quickly as possible?

But fast charging has its price.

snabbladdare fast chargers

Greater chance of overheating

Faster charging means faster movement. Faster movement means more heat. Heat, in turn, can adversely affect the battery over time. When the battery gets hot, its capacity deteriorates. Even if you charge the battery carefully, in shorter periods, and keep it at about 30 degrees Celsius, the battery can lose up to 20% of its capacity over a year. If the battery gets hotter, you lose capacity even faster.

Less capacity in the battery

In prevent the electrons to jump from the negative side directly to the positive side, but instead give power to a unit on the road, there must be a partition between the poles. In a battery that can be charged quickly, this partition must be much thicker than it needs to be in a regular battery. This is to help keep batteries stable. As the partition takes up more space, the space for the capacity, itself, becomes smaller. And in the ultra-fast chargers, you need to take this even further and divide the battery into two separate batteries, something that is very bulky.

Slower charging towards the end

When you read about how extremely fast the new chargers are, the manufacturers like to show only the first bit. It usually sounds like this:

“Charge your phone to 50% in just 5 minutes”

This is because the amount of watts that are often marketed, is the maximum watt. Something that is achieved during the beginning of the charge period. The more your battery is charged, the slower the charging will be. This is to are protect the battery.

A charger of 60 watts is thus not twice as fast as one of 30 watts. And the difference in speed will be smaller, exponentially. So a 120-watt charger is therefore far from twice as fast as a 60-watt charger.

The trend has had an opposite effect – Slow-charging

When fast chargers quickly became a hot topic, extra slow chargers slowly but surely become just as hot. Some suppliers already market slow-charging as a new feature for their products. Something that may sound completely crazy at first glance but which hopefully becomes clearer after reading this blog. Unfortunately, slow charging is not something magical that will make your battery last forever. All charging, fast or slow, wears out your battery, more or less.

That said, fast chargers are awesome when you are in a hurry and realize that the battery will soon run out. Then you can give your battery a quick kiss with the charger and in just minutes you will have the battery to last, at least, a few hours. In addition, manufacturers make these fast chargers with smart transformers, so-called power bricks, which communicate with the battery. In this way, the charge can be switched off when the maximum charging capacity is reached, which saves the batteries from wearing out too quickly.

So yes, charging too fast can have a negative effect on your battery. Many manufacturers say that the sweet spot is about 30 watt. Fast enough but not so fast that it has too negative effects on your battery.

Read our blog post about how fast charging works here


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