We are often asked if it is okay to leave a notebook computer connected to one of our USB-C docking stations with Power Delivery for extended periods of time. The short answer is yes, it is no different from leaving the laptop connected to the manufacturer's original USB-C power supply for the same time. The long answer is yes for modern laptops, and maybe for older (1990s-early 2000s laptops) and involves going into the different battery technologies used in consumer electronics devices.
Another common question is if it is possible to use the docking station but to disable powering and charging the computer. When a modern notebook computer runs on battery power it will often set the system to a reduced power state which may impact performance, or connected devices and we recommend always powering the computer when using a desktop docking station. For all of our docking stations that provide power to the host computer this will not affect the lifespan of the computer's battery.
Modern Laptop Batteries: Lithium-Ion
Lithium-ion (li-ion) batteries are found in a wide range of consumer electronics from notebook computers and cell phones, to electric cars, power tools, and wearable electronics like wireless earbuds. Li-ion offers fast charging, high-current discharging, fairly long service live compared to other rechargeable battery technologies and are relatively inexpensive.
The life-span of a rechargeable battery depends on many factors including age, temperature history, charging patterns, the chemical composition of the specific battery, and usage. For example batteries stored at 100% charge will degrade faster than batteries stored at 50% charge, this is why most consumer electronics devices arrive from the manufacturer with between 25% to 75% charge.
Lithium-ion batteries are consumable components, however in most modern computers, cell phones, and tablets these are not user serviceable components. To help maintain the battery all modern computers and most consumer electronics will include battery charge and protection circuits. These can be fairly simple, charging up the battery at preset rates depending on the charge level to help maintain the battery life, or complex software controlled charging that monitors battery temperature, voltage and current draw to maintain the fastest charging while maintaining the battery longevity.
Modern notebook computers can be left connected to the original power cable or a docking station with charging capability for extended periods, and do not benefit from regular discharge/recharge cycles. Our docking stations with charging capability rely on USB Type-C Power Delivery to power and charge compatible computers. USB Type-C Power Delivery is a negotiated charging protocol between the host computer and the docking station or USB Type-C power supply, this allows the computer to draw only the power it requires, and even select the best voltage level for powering the computer. In combination with a computer's built-in battery charging controller the computer is capable of maintaining the battery's optimal state even when left connected to a power source for an extended period of time.
Legacy Laptop Batteries: NiCad and NiMH
Older laptops, from the 1990s and some early 2000s, as well as some consumer electronics, and most rechargeable AA or AAA battery replacements use Nickel-Cadmium (NiCad) or Nickel-Metal Hydride (NiMH) batteries. These batteries are slower to charge and discharge than li-ion batteries, and require very simple charge controllers, and in some cases can even be trickle-charged ( very low-current continuous charging ) if desired.
These batteries generally don't have smart charging controllers and to prolong the life of the battery required "training" or fully discharging and recharging the battery every so often. Many laptop manufacturers recommended fully charging and discharging a new laptop 2-3 times to train the battery, this is not necessary with modern laptops.
Modern notebook batteries are managed by the computer's built-in battery charging circuit, and require little to no user intervention to maintain optimal battery health. It does not harm the battery to leave the computer connected to an external power supply, so long as the computer is being used regularly. If the computer is to be stored for a prolonged period then discharging the battery to between 50-75% can help to maintain the battery life.
Batteries are consumable components and degrade over time, however modern notebook computers can extend the battery life generally to meet or exceed the life of the computer's other electronic components.