The life we live today is powered by devices, lots of devices. It is not uncommon for someone to have more than four or five personal electronic devices which often include; a smartphone, a personal laptop, an iPad or tablet, a Bluetooth headset, and a smartwatch. The proliferation of personal gadgets implies that you have to take turns charging them since they are all electronic devices. The truth is most of these gadgets are complementary and your day will not be the same without any of them, so the fear of forgetting to charge a gadget is a real and understandable fear. 

Can I Leave My Smartwatch Charging Overnight?

Can you imagine getting on the train or driving to work and realizing that your Bluetooth headset has zero battery percent capacity? Or realizing that all your efforts to achieve your daily steps and physical activity target by avoiding the elevators and using the stairs are not documented because the smartwatch is out of battery capacity? It is simply a disaster that has the capacity of being a mojo killer and simply derail your day. 

One easy way to deal with the charging demands of your electronic gadgets to make sure they are all fully charged during the day is to leave some of them charging overnight. An easy choice of a gadget to be charged overnight is the smartwatch. Since it is wound around your wrist all day, it is almost impractical to find time to charge it. But is it safe to leave the smartwatch charging all night long? Are there any significant risks to performance and longevity? All of these questions are answered in this article. 

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Smartwatch battery 

Like most other modern electronic appliances, the smartwatch uses a Lithium-ion battery. It is the most advanced rechargeable battery and it is the same battery type found in smartphones and newer laptops. One of the reasons for the wide and growing adoption of this battery type is that while all rechargeable batteries tend to lose capacity over time, the Li-ion battery can reduce the loss of capacity over some time significantly. 

Trickle Charging

When you plug your smartwatch into a power outlet overnight, the normal charging process occurs until a 100% charge is achieved. After the achievement of the 100% charge, trickle charging commences. According to Wikipedia, trickle charging is the process of charging a fully charged battery at a rate equal to its self-discharge rate. What this means is that the battery will remain at a fully charged state for the entire time it remains plugged to the power supply point since the device is not put to use and hence the charge is not extracted. 

Now, in some batteries, the setup is configured in such a way that it can regulate the amount of electricity absorbed from the charging system. This is often not the case with Li-on batteries which are present in the smartwatches. Generally, the Li-ion battery’s setup is not configured to regulate the electric charge flowing through the charging system even after the state of full charge has been reached. The implication of this is that the same amount of charge is flowing through the charging system to the battery both at points of zero or low charge and full charge state. 

This excess flow of charge despite the lack of demand for the charge due to the lack of activity on the device will then translate to heat and this is responsible for the overheating that is commonly observed when devices like smartwatches and smartphones are charged for prolonged periods. Overheating is not good for the health of your smartphone’s battery. 

Duration of Charge 

Depending on the state of charge, whether the capacity is fully drained (not advisable) or just at a low point, an average battery takes between one and two hours to reach a 100% charged state. The recommended daily sleep duration for an adult human is between 7 to 8 hours. 

Let’s assume that you are sometimes distracted by social media and Netflix, hence you don’t go to bed on time and end up getting 6 hours of sleep on average. If you plug your smartphone to charge overnight, you will be charging it for an extra four hours, above and beyond the required two hours. This means overheating the device for four hours. 

Battery life 

Most smartwatch batteries have a higher capacity and consume less energy compared to the smartphone because of the lower demands. These batteries can last from anything between two to four days, so they are not one of your gadgets with a high charging requirement. 

You can simply charge them every other day or every three days and they will be just fine. This makes it easier to plan for their charging as it does not have to be the last minute and urgent thing such that you will have no choice but to plug them in all night.

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Overcharging results in overheating which leads to instabilities in the composition of the chemicals present in the battery setup. This can result in quicker aging of the battery cell, that is it will hold less and less of it’s charge capacity over time and ultimately the lifespan will reduce. 

Apart from this reduction in the lifespan which is a huge consideration for most users of smartwatches, have you forgotten about climate change? The world is big on sustainability right now. There are frantic calls and proposals urging people to conserve energy and protect the planet. Ultimately, all the present-day energy sources including renewables take a toll on the planet in the long run and we have gone too far already in not caring so much that every little action that conserves the most seemingly inconsequential amount of energy counts. 

It counts especially because of the habit-forming tendencies which will be transferred to other aspects of life. So, right now is not the time to be leaving devices plugged to charge overnight. 

Most smartwatches and chargers are equipped with fast-charging technologies that can achieve 100% charging capacity within a really short time. There is no reason to leave a device plugged overnight when it can be fully charged in 45 minutes after you wake up.