When it comes to charging equipment such as smartphones and laptops, everyone seems to have strange customs. For example, people let the battery of their new gadget completely discharge before using it or the plug is immediately removed from the socket when the battery is full. But how do you best handle your battery? We find out by having experts explain how batteries work.
Batteries, also known as batteries, are one of the most important parts of electronics. After all, your expensive phone, laptop or handy e-reader won't work without a battery. Yet few people know how a battery works and there are many myths on the internet about charging and discharging batteries. Time to get some clarity. In this article, we focus on lithium-ion batteries, the type of battery most commonly used in consumer electronics.
Charging new battery
When you take your new gadget out of the box, you'll want to set it up and use it right away. But wait: on the internet it says that you must first charge the battery and only then can you start using the device. Is that right? No, says Prof. Peter Notten, professor of Energy Materials and Devices at Eindhoven University of Technology. “A lithium-ion battery has already been charged and discharged a number of times at the factory, intended to get off to a good start. Charging the battery first or not has, as far as I know, no influence on the battery life.”
dr. Marnix Wagemaker, professor and battery researcher at Delft University of Technology, agrees. “With lithium-ion batteries, this makes no difference.”
That makes a difference, so you can use your brand new electronics immediately the first time. Unless the battery is (almost) empty, of course.
Charging the battery first or not has, as far as I know, no influence on the battery life.Cheap chargers can be dangerous
There is a good chance that you will not only charge your phone, tablet and other gadgets with the original cable and plug, but also with non-original accessories from, for example, the discount store or a Chinese webshop. Unbranded chargers from such stores are admittedly much cheaper, but that lower price has to come from somewhere. The parts used in dirt-cheap cables and plugs are often of lower quality and are sometimes even dangerous. Professor Notten therefore calls the use of cheap, non-original accessories 'unwise'.
“The charger has to be completely tuned to the battery, the communication between the two is extremely important. The accuracy of the charger largely determines how the battery ages.” In the case of a so-called mismatch between the charger and the battery, according to Notten, 'weird things' can happen, such as a short circuit.
Wagemaker adds: “The charger that comes with the product has been carefully thought out about how much voltage it can supply to the battery, for example 4.2 volts. If you use another charger that has a maximum of, for example, 4.4 volts, your battery will be charged at too high a potential. If it is slightly too high, it is mainly bad for the life of the battery, but too big a difference can indeed be dangerous.”
USB-C
Be extra careful with devices with a USB-C connection, because USB-C supports higher voltages than the well-known micro-USB 2.0. More and more electronics have a usb-c port and although there is a clear description of the usb-c standard, not all manufacturers adhere to this. For example, the USB-c cables of the OnePlus 2 and 3 telephones did not meet the standard and dubious accessory brands still produce (cheaper) cables and plugs that have a higher maximum output than is desirable. This is dangerous as it can lead to an overheated battery which in turn can catch fire or explode. Before you buy a USB-C product, check carefully whether the maximum output in volts and amperes corresponds to that of the original product accessories. Or buy an original cable or plug, then you know for sure that you are in the right place.
charge overnight
“In principle it is possible,” says Professor Notten. “Lithium-ion batteries use the well-known CCCV charging mode where the first half of the battery charges quickly and the second half more slowly to avoid dangerous situations. But if the battery is left on the charger for a long time, for example overnight, small side reactions do occur that reduce the life of the battery.” You don't notice that effect after a few months, it does take longer.
Wagemaker also calls it safe enough to hang equipment on the charger at night, provided you use original accessories. “If the charger is good, it knows that the battery is charged and it stops. There is no longer any current flowing through it, so there is no danger.” Yet the professor does not charge his equipment at night, just to be on the safe side.
The experts have one more urgent advice for those who charge their phone under the pillow at night: stop immediately! Notten: “It should be prohibited, because a battery cannot lose its heat under a pillow. And a battery should not get too hot, because a higher temperature can lead to all kinds of strange things such as short circuits.” Manufacturers such as Apple also warn against battery overheating. On its website, the iPhone maker says that the lithium battery in the iPhone can be damaged by high temperatures. Apple therefore advises customers to remove any case from their device if the device becomes very hot while charging.
The best temperature for charging a battery is room temperature. According to Professor Notten, charging a telephone, laptop or tablet in full sun is absolutely not good for the battery because the negative side reactions of charging are faster at higher temperatures.
Calibrate battery
If the battery life of your device is (suddenly) disappointing and you have no explanation for it, you can calibrate the battery for a kind of reset. For example, Nintendo recommended this method last year when its Switch game console was plagued by a battery problem.
Professor Notten indicates that this method works for the batteries that were used in the past, but he does not believe that it plays an important role in the current lithium batteries that are in tablets and laptops, among other things.
Battery drains faster when it's cold
At a low temperature, the voltage of the battery goes down and the colder it is, the faster it goes. Professor Notten: “When the battery reaches the lower limit of the voltage, it stops. And so does the device. It may appear empty, but it is not. If you heat it indoors to room temperature, it will work again.” His reasoning is supported by fellow professor Wagemaker. The advice is therefore to keep your gadget warm in the winter by putting it in your bag or jacket pocket.
Fast chargers and wireless chargers?
According to Wagemaker of TU Delft, it is clear why fast chargers are worse for the battery than slower charging. “With fast charging, current is continuously pushed into the battery with a higher voltage, often as high as the battery allows. That's great, because the battery charges quickly, but if you always use a fast charger, you always charge at the limit of the battery. This accelerates the aging of the battery and therefore has a negative effect on the lifespan.”
In principle, this is no different with wireless chargers with a high maximum voltage, says Notten. Wireless charging of the battery is a technique that is especially popular on (more expensive) smartphones. Charging works roughly like this: you plug the charging station into the socket and place your smartphone on the station, after which the phone converts the magnetic energy into voltage to charge the battery.
An American journalist recently reported based on his own research that the battery makes more cycles with wireless charging than with wired charging and therefore ages faster. Several experts have recently informed Nu.nl that this claim is unlikely. One of them explains that the battery treats the energy received in the same way as when using a wired charger. In addition, to prevent damage to the battery and other phone components, the most widely used wireless charging (Qi) standard requires manufacturers to build a shield around the coil of the smartphone.
Load up to 100 percent?
A fully charged battery gives a certain feeling, but charging a battery to one hundred percent is bad for the lifespan. “It all has to do with maximum tension,” explains Professor Notten of Eindhoven University of Technology. “That voltage affects the life of the battery. Therefore, stay away from the top and bottom of the charging and discharging process.' According to Notten, it is better to charge your device's lithium-ion battery to eighty or ninety percent and not let it drop below twenty percent.
"It's better than completely draining the battery." The American Battery University, one of the best-known companies that tests batteries, underlines this, as do smartphone manufacturers such as Samsung.
Professor Wagemaker of TU Delft agrees that the battery life is best if the capacity is kept between twenty and eighty percent. He underlines Notten's reasoning: “If possible, avoid the end of charging and charging from zero, i.e. an empty battery. When you think about the lifespan, you don't use the entire capacity of the battery – but then you give away some power.”
A battery that is never completely full must therefore also be charged faster. Not ideal, but charging more often is better for the life of the battery, say battery testing company Battery University and professor Notten.
Charging a battery to one hundred percent is bad for its lifespanLithium-ion battery life
A device with a battery always wears out. Many electronics such as smartphones and tablets have a flat lithium-ion battery, Wagemaker is the first to explain. This type of battery takes up less space than a cylindrical lithium-ion battery, but also has a shorter life. Because laptops, for example, are becoming thinner, they are also switching more often from a cylinder shape to a flat battery. How long the battery lasts differs per battery and therefore per device. Each time the battery is fully charged, it counts as a cycle. A flat lithium-ion battery lasts on average between five hundred and seven hundred cycles.
According to Wagemaker, those who use their battery economically by charging it slowly and keeping it between twenty and eighty percent can last noticeably longer. “If we do something like this in the laboratory, we get noticeably more cycles, ie charges from the battery. You notice that especially after the seven hundred.”
Notorious Samsung Galaxy Note 7
From time to time, reports of dangerous chargers, cables and products surface. The Samsung Galaxy Note 7 is perhaps the most famous of recent years. The device came out in August 2016 and within a few weeks there were reports that the device was a fire hazard. A number of consumers had their phones caught on fire or even exploded. Samsung therefore started a recall at the beginning of September and soon afterwards came up with new Note 7 models that would have a safe battery. When these new copies also spontaneously caught fire in some cases, it was decided to recall the Galaxy Note 7 worldwide. Stores returned unsold models to the manufacturer and millions of customers were sent a fireproof box to return the device. The fiasco cost Samsung more than ten billion dollars and dented the brand's reputation. Samsung later concluded from its own research that production errors had crept into the battery, which made some units too large and too small and overheated during use.
