Wireless charging has been around for a while and is increasingly becoming more popular for phones. There were some limitations when it first started but thanks to technological improvements, problems like slow charging and the need for precise placement are melting away.
If you have or are considering switching from wired to wireless charging for your phone, you should probably do a lot of research to learn how the technology works, as well as its pros and cons. Our article on ‘iPhone wireless charging’ is a great place to start.
In summary, wireless charging allows you to charge your phone’s battery cable-free. Your phone contains a receiver induction coil while the wireless charger contains a transmitter coil. When these two devices are brought close to each other, the transmitter coil generates an electromagnetic field, which the receiver coil converts to electricity for powering the phone battery.
Back to the topic at hand, modern smartphones contain a rechargeable lithium-ion battery, which charges faster than traditional batteries. But as we know, our battery charges don’t last long and you’ll be lucky if yours gets through the day without losing all of its juice.
Chances are you leave your phone charging wirelessly overnight so you can start a new day with a fully charged phone. Many people choose overnight charging to avoid being without a phone during the day, but is this a good idea?
As wireless charging increases in popularity so is information about its effects on phones. You’ve probably heard that it’s okay to leave your phone charging wirelessly overnight and you’ve read articles that support the opposite as well.
So what claims about wireless charging are true and what aren’t? This article will demystify the subject so you find out whether or not it’s bad to leave your phone charging overnight. Without much delay, let’s get right into it:
Table of Contents
Facts about Wirelessly Charging Your Devices Overnight
It only takes an average of 3 hours to fully charge a wireless phone. Therefore, when you leave your phone on a wireless charger overnight, it continues to charge for about 5 more unnecessary hours. What happens when your phone is fully charged? Does it continue to draw current? Does it generate more heat that could damage the phone or battery? Let’s find out:
What happens to your phone during wireless charging when it reaches 100%?
Modern phones are called smartphones for a reason. They contain various built-in chips, including protection chips that will protect the phone automatically.
Once your battery reaches 100%, the protection hardware within the phone will stop the current from coming in, thereby safeguarding your phone from taking more charge than it should. What this proves is that you cannot overcharge your phone by leaving it wirelessly charging overnight.
The smartphone is, however, constantly draining its battery due to the several operations it performs in the background even when you’re not using it.
For this reason, it will continuously draw in current every time it falls to 99% to bring it back to full charge. This is called trickle charging and could happen several times while your phone charges overnight.
Secondly, battery manufacturers often decide the amount of energy that can be stored in the cell. They decide the upper and lower cut off voltage.
This means that it’s impossible to exceed these limits just by putting your phone on the wireless charging pad overnight. You also can’t drain the cell beyond the lower cut off voltage. This brings us to the second fact, that you can’t overload or over-discharge a cell.
What happens to the charger when the phone is fully charged?
Wireless charging is not a one-way transmission. Your smartphone may have protection chips but what of the charger that’s transmitting the power? Good quality wireless chargers are also equipped with protection chips.
When the transmitter (charger) detects that the receiver (your phone) has stopped taking in charge, it will also stop delivering current. Wireless charging pads will safely trickle-charge your battery to keep it fully charged at all times.
Does it Mean Charging Your Phone Overnight Is Fine?
From the discussion above, we can see that smartphones and wireless chargers have the technology and built-in system to protect your device from overcharging. But this doesn’t make it totally fine to charge your phone overnight. There are a few notable problems that you may face when you charge your wireless phone for unreasonably extended periods.
For those with wireless phones, you’ve probably noticed your phone heating up when it’s charging. That’s because wireless charging pads produce heat during charging, meaning overnight charging might result in overheating. This issue is not just specific to wireless charging as heating is a side-effect of any kind of charging.
These safety issues can be avoided, or at least minimized by using high-quality wireless chargers to charge your phone. We recommend buying Qi-certified chargers as they have been tested for safety and effectiveness. They have overvoltage, overcharge, and temperature control protection, and also meet FOD standards. This ensures their safety, as well as the safety of your phone and nearby objects.
That being said, the discussions above only focus on safety issues. When it comes to the battery’s lifespan, it’s a whole other story.
Does Charging Overnight Hurt Your Phone’s Battery?
While it’s true that you cannot overload the battery by charging your wireless phone overnight, keeping it at 100% throughout the night can cause it to degrade quickly. But this is not because you’re cramming in more charge than it can handle. So, how does prolonged wireless charging degrade battery?
Rechargeable Li-ion batteries are basically doomed from the start. They are in constant decay from the moment they are first used and gradually lose their capacity (ability to hold a charge). This process can be hastened by your actions though.
When charging a phone, Lithium ions swim across the cathode to the anode, generating a kind of rock-salt that forms an electrically-insulating crust over the cathode. The build-up grows overtime, shrinking the battery capacity.
As mentioned earlier, trickle charging occurs in an overnight wireless charging session, which prolongs charging and hastens the build-up. This will, in turn, degrade your battery much faster.
Trickle charging can also increase your phone’s temperature. High temperatures further excite the lithium-ion in batteries, leading to even quicker deterioration. Studies show that temperatures higher than 95°F (35°C) can permanently damage battery capacity.
Prolonged wireless charging also strains the battery from the high voltage as it has to work to keep its full charge. Did you know that you don’t even need 100% charge from your phone’s battery? Experts agree that the optimal charge level for smartphones is 20%-80%.
Li-ion batteries are strained when operating at full charge of 100%. And, when it does this continuously with night after night of overnight wireless charging, its recoverable capacity will decrease and leave a dent in the battery capacity.
What about letting your phone drop to 0%
Completely discharging your iPhone will also wear out its Lithium-ion battery faster than normal. There are several different ways that this happens.
First off, when the battery is fully discharged to 0%, the chemical reactions within it will begin to affect the electrodes in the battery. This could break the safety circuit and perhaps make it impossible to even recharge the battery.
Secondly, if you let the battery discharge to 0% and don’t recharge it soon enough, it may become incapable of holding a charge, which decreases its efficiency.
The last way to explain this is by using cycle limits. Batteries measure their lifespan in charge cycles. A cycle is completed when you use 100% of your battery.
For example, if you use 50% of your phone’s charge today and after recharging it use another 50%, that’s one cycle. When you drain lithium-ion batteries all the way to 0%, it counts as a full-charge cycle. Doing this regularly decreases the battery’s total life.
Smartphones have different standards, but it’s universally agreed that a battery will degrade after a certain number of charge cycles (usually 500-1000 charge-discharge cycles). iPhones, for instance, will only retain up to 80% of their original capacity after 500 charge cycles.
With new technological trends emerging every other time, phone manufacturers are always looking to stay ahead of the competition by providing better phones with the latest technology. With everyone wanting to have the latest phone, many of us don’t expect to keep our phones for much longer than two years.
Experts say that the loss of battery capacity, especially with high-quality devices like iPhones, becomes noticeable in the second year of use. If you replace your phone every other year, then you probably don’t have to worry about the effects of overnight charging on your battery’s lifespan since you’ll have a new one before the life charges in your old one are depleted.
But if you are hoping to hang onto your phone for a couple more years, then perhaps you should resist the urge to charge it for extended periods. If you can’t resist the convenience that overnight wireless charging brings, minimize the possible impact of charging overnight.
How to Delay Battery Degradation When Charging Overnight.
Limit the time spent at full charge
Overnight charging will surely charge your phone to its full capacity and maintain it there throughout the night. We’ve already seen how leaving your phone at full charge can damage its battery. Therefore, do the following to minimize the time your phone spends at a full charge:
1. Plan your nighttimes charging so the phone is full before you sleep. For instance, if you have a fixed bedtime, consider putting your phone on the wireless charger 2 hours earlier and depending on the charging speed, the battery level should be up by the time you go to sleep.
2. Use a slow wireless charger without fast charging. This will charge the phone at a much lower speed and although it might still spend a few hours at full charge, it will be much lesser.
3. Remove the phone from the charger at night. This doesn’t mean you set an alarm 3 hours into sleeping just to stop charging. Rather, if you do wake up in the night to go to the bathroom or from nightmares.
Reduce heat while charging
As mentioned earlier, heat is a result of charging and charging overnight only increases the chances of overheating. High temperatures are bad for the battery’s lifespan, so reduce heat by:
1. Charging where the heat dissipates: Accumulated heat will affect your battery’s lifespan so the cooler the charging spot, the better. Don’t put your charger and phone on the bed or somewhere with poor ventilation. A good charging spot is on flat, open, and sturdy surfaces like on the table, floor, or bedside cabinet.
2. Charge your phone naked: Those thick casings wrapped around your phone trap in heat during wireless charging. Removing them will allow for ventilation and even increase wireless charging efficacy.
3. Close background apps and services while it’s juicing up overnight: GPU and graphics-heavy apps like games generate more heat during charging, so close them before leaving you phone to charge overnight. This will also reduce the energy that the phone uses, thereby reducing the trickle charge time
Are Wireless Charging docks Ideal for Charging Overnight?
Docks are convenient for overnight charging because they support multiple devices and can charge them simultaneously. Wireless charging, in general, is much more convenient and more battery-friendly than wired charging, especially when charging overnight.
Smartphones and quality wireless charging docks are smart enough to stop receiving or transmitting power when the battery is fully charged. However, if your phone is not aligned properly on the wireless charging pad, there’s a good chance of finding a flat battery in the morning.
If you intend on charging your wireless phone overnight, you need to choose a reliable charging station that allows you to charge more freely without restricting the charging position. Be sure to read wireless charging station reviews to find the best possible option for you.
With that said, try not to leave your phone on a wireless charging station once it has hit 100% charge. We have already seen why prolonged charging is bad and how you can minimize the negative impact of wireless charging overnight.
How Do You Select A High-Quality Wireless Charger?
Having read this guide and several other articles about wireless charging, there are many who have decided to embrace the wireless charging technology. While using a wireless charger is pretty simple, picking the right one is surprisingly challenging.
The wrong charger may not function, which is the least of your problems as it can affect your device’s charging capabilities and even cause irreversible damages. Wireless chargers are ubiquitous and feature several variables that can make all the difference.
We are going to look at some of the most important ones to help you make the right choice when shopping for the best wireless charger. Here’s what to consider:
Supported charging standard
Until recently, there were three different wireless charging standards that you had to be aware of when buying a wireless charger: the Wireless Power Consortium (WPC), the Alliance for Wireless Power (A4WP), and the Power Matters Alliance (PMA).
Qi technology by WPC has since become the most popular of the wireless charging standards. So much so that Powermat (the founders of PMA standard) joined WPC to support the Qi standard. This technology has been adopted by Apple, Samsung, Google, and many top OEMs.
That being said, it’s very important to check what standard your smartphone supports. If you have multiple devices with varying charging standards, consider a dual charger that supports multiple standards.
Phones have different power capacities. Your phone’s power compatibility can make a huge difference on how fast and efficient a wireless charger powers it up.
For instance, some Samsung phones can charge at a maximum speed of 9 Watt, iPhones at 7.5 Watt, while the fastest-charging wireless phones can handle up to 10 watts. Wireless chargers usually range between 5 to 10 Watts although there are Qi wireless chargers that can transfer up to 15 Watts.
Chargers that output 5 Watts will still charge your phone but at a slower speed. We recommend going for a higher power wattage charger for faster charging and future usage.
If the charger has output wattage higher than what your phone can handle, don’t worry because Qi-certified chargers will only output what your phone is capable of handling. Having said that, note that not all phones support fast-charging, which is a selling point for some wireless chargers.
The same way phones come in different sizes, shapes, and styles, so does wireless chargers. Home wireless chargers are available in pad form that lies down flat on the table or stand designs that hold your phone in a semi-upright angle.
The former is easy to use and more ideal for charging overnight. However, the latter is much preferred because it allows you to use the screen while the phone is charging. There are also convertible chargers that can lay flat or stand in an angled position.
If you’re looking for a wireless charger for your car, consider the mount type. When it comes to size, it depends on the amount of free space you have on your table, desk, or even car. A charger with a small pad is ideal if you have just one wireless phone. If, on the other hand, you have multiple wireless devices, a charging station with a large surface would suffice.
One of the most frustrating aspects of wireless charging is that you have to align the phone and the charger’s coils correctly (although it shouldn’t be much of a problem with good chargers). It’s, therefore, important that your charger has a good grip that can firmly hold the phone on the charging surface. Otherwise, a slight bump might knock the two coils out of alignment, thereby disrupting charging.
LED indicator lights
It seems like such a basic thing to include charging lights into wireless chargers but you’ll be surprised to find that some don’t have them. The best wireless chargers feature LED indicators, which provide information about a charge.
For instance, they will light up when your phone is correctly placed on the charger and also use a variety of colors to indicate the charging status. Note that some chargers have extremely bright LED indicator lights, which can prove distracting at night. If this is a concern for you, choose a unit with dim LEDs or one that deactivate the lights after a few seconds.
Cost is always a major determinant when making any purchase. You want to ensure you choose a wireless charger that’s within your budget but also offers good value for money. You can get a good-quality charger in the $10-$40 range, but others run up to $70.
The pricier chargers tend to come with more features and can allow you to charge multiple devices simultaneously. While it’s true that price and quality go hand-in-hand, expensive models don’t always equal high quality. So, be sure to read wireless charging pads reviews to see what others have to say about a particular charger.
Qi-certified chargers means they have been tested by WPC and found to be safe and in line with WPC charging standards. The Qi certification provides assurance that a particular charger won’t damage your phone since they have safety features such as overcharging and overheating protection.
Qi-certified wireless chargers are usually listed on the WPC database, have the Qi logo printed on them, or come with a Qi certificate. If it lacks all of these stamps of approval then it’s not Qi certified.
Some wireless chargers support charging with the case on while others don’t. While it seems simple to simply remove the case whenever you want to charge your phone, it can get tiring when you have to do it every now and then.
In that case, consider a charger that can charge your phone through a case. Keep in mind that if you have a thick case, it may inhibit or slow the charging process. Standard wireless chargers can penetrate thin cases and you may need a powerful one to charge a phone with a rugged cover.
The better solution would be to buy your phone a case that works with wireless charging. We recommend a carbon fiber cell phone case because it’s thin and lighter than metal but provides more protection than plastic.
Multiple charging coils
Wireless charging is only possible when the magnetic fields of the transmitter and receiver coils are properly aligned. The ease of aligning these coils varies between chargers. Single coil designs are pretty common in charging pads, but they can be a bit frustrating when you are trying to align your phone.
Multi-coil designs, on the other hand, increase the alignment area, meaning you don’t have to be very precise when you lay down your phone. Some chargers with multiple charging coils can charge a single device at a time, but others allow you to charge more than one device. Chargers with multi-device support are more convenient if you have multiple wireless devices.
In view of the many different wireless chargers you can buy, make sure you get a unit that’s not only functional but also best suites your taste. Most importantly, go through online reviews to see what previous users of a particular wireless charger have to say about its capabilities and features before making a purchase.
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