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.

Conclusion

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.

The humble Universal Serial Bus, more commonly known as USB, has evolved to be much more than just a way to connect a mouse or keyboard to your computer. With the proliferation of power-hungry portable devices that charge over USB, we’ve all come to expect USB to operate as a Universal Source of Battery charging but, unfortunately, it’s just not that easy.

Modern Charging Standards

USB-C and USB Power Delivery (PD) Standard Power Range (up to 100W)

The USB-C connector and USB-PD specification up to revision 3.0 enable charging at up to 100W (typically 96W to 98W real-world maximums per IEC regulations). However, the protocol for negotiation between host and charger can be complex and hard to understand. Early USB-C PD implementations (starting in 2015) could be unreliable, and many manufacturers of devices used proprietary implementations to block universal charging solutions (docking stations, third party chargers, etc). With time and several updates to the PD spec there have been vast improvements in the consumer experience, though we do still encounter scenarios where there may be compatibility issues that are beyond our control (3rd party devices).

Generally speaking, USB-C PD is an intelligent charging standard with the ability to deliver variable voltage and amperage charging rates (equating to the final charge wattage). USB-C PD defaults to 5V and can adjust dynamically depending on the implementation of charger and device up to 9V, 12V, 15V, and 20V up to 5A. Not all USB-C ports on devices (like a hub or dock) offer PD charging, some USB-C ports may only offer standard USB 3.0 power at 900mA. Others may offer more at commonly found values of 1.5A or 3A at 5V (7.5W and 15W). Likewise, not all USB-C devices (like a laptop or tablet) will have the ability to charge over this connection, some still require a dedicated DC barrel jack charger that shipped with the device.

Without going into overly complex detail, USB-C PD can either use a set signal on two communication lines through a USB-C connector and cable (CC1 and CC2) which is determined by either a set resistance value and subsequent voltage reading, or two-way data communication can be established where the charger can tell the attached device how much power it can supply and/or the device can request how much power it needs. Once a contract has been negotiated and established, charging may then commence.

As an example, a laptop may require 65W of power to charge, this would most likely need 20V at 3.25A. When connecting this laptop to a USB-C charger (or dock, etc) a series of events as outlined above will occur. If connecting to a lower wattage charger, say 60W for this example, the laptop and charger will try to establish the fastest possible common charging rate which would be 20V 3A. In most cases this will work perfectly fine and the laptop will charge slightly slower than it would with the original 65W charger it shipped with. 

But what would happen if connecting to a higher wattage charger, like 96W or 98W? Many would expect their laptop would be damaged, however, because USB-C PD is intelligent some two-way communication will occur, and the charger should negotiate the fastest possible rate that is requested to deliver 65W. It is also important to note that chargers do not "push" power to a device, rather, devices "pull" power as needed. As long as the charger does not output a voltage higher than what the device is expecting damage won't be possible. Because USB-C defaults to 5V, a higher voltage will not be output unless that higher voltage has been requested and properly negotiated.

What about a laptop that needs more power, like 135W or higher (which is above the USB-C spec)? If the laptop supports USB-C PD through its USB-C connector despite needing more power than can technically be provided, it will try to charge as fast as the charger can offer. Due to the higher power requirements charging may be slower but still gain battery percentage, or the system will be "treading water", only able maintain a stable battery charge without gaining. In some situations like this, the system when under extreme CPU or GPU load may supplement more power by draining the battery while also drawing power from the charger. This may lead to a slow drain and would eventually run out of power until the load is reduced. In some rare situations like this, the laptop may only be able to gain battery while in sleep mode or off. 

USB Power Delivery (PD) Extended Power Range (up to 240W)

The new USB Power Delivery revision 3.1 specifications allow for the delivery of up to 240W via a USB Type-C cable (an increase from the previous 100W max). The previous Power Delivery range has been relabeled as Standard Power Range (SPR), and the new specifications (between 100W and 240W), have been labeled as Extended Power Range (EPR).

For a more in-depth look feel free to check out our blog post on this topic here: https://plugable.com/blogs/news/what-is-240w-usb-extended-power-range-epr

Thunderbolt 3 / Thunderbolt 4 / USB4

Thunderbolt 3, Thunderbolt 4, and USB4 all share the USB-C connector specification and utilize the aforementioned power and charging abilities introduced by USB-C.

Qualcomm Quick Charge (QC) 4/4+/5

Qualcomm QC 4, 4+, and 5 are cross-compatible with both USB PD and USB-C specifications, falling back to PD in the event of a compatibility issue. Currently, Plugable does not offer any QC devices.

Legacy Device Charging

 A common question we receive is whether it is okay to use a dock or hub that provides different wattage compared to the power adapter included with the laptop, especially if the dock or hub provides less power than the OEM charger. Short answer: for most use cases, it’s fine! And when using standards-compliant docks, hubs, and chargers like those from Plugable, it’s always safe.

When considering whether a dock or hub has enough power to charge a host, it is helpful to understand how little power is consumed most of the time you’re using your system.

Some details why 60W charging is more than sufficient for typical workloads:

All laptops will come with a power supply directly from the manufacturer. This power supply usually supports the maximum charging rate that the host can support (45W, 60W, 100W, 140W, etc.). However, modern systems are designed to be power efficient while managing their power consumption dynamically, typically using just a fraction of their maximum power draw under typical workloads. Additionally, to preserve battery longevity, most devices will reduce charging rate even when a higher wattage charger is connected. Note that Gaming or Workstation laptops, typically including 180W+ power adapters, may have special power requirements.

Even during high-power tasks such as video editing, hosts may only pull greater than 60W for brief periods of time. In these instances, you may notice the battery charges slower, or in some cases even slowly discharges. This is not indicative of a faulty power supply or a problem, just a difference in power consumption vs power delivery.

In some cases, for laptops that can charge at higher than 60W over USB-C, it can take longer for the 60W charger to fully charge a host from 0-100% than a 100W charger for example. However, this is usually only relevant for the first 50 or so percent, as the host limits the charging rate exponentially as the battery gets closer to being fully charged. In the 80-100% range, laptops are typically charging at less than 15W. This means that in a configuration where you are connected to the power adapter for long periods of time, like an entire work day, the 60W charger will be functionally identical to a higher wattage power adapter.

Windows laptops – particularly those from Dell, HP, or Lenovo –  may send pop-ups in the OS or messages on boot warning you about a lower charging rate. The messages could be similar to the following:

• “You have plugged in a lower wattage power adapter, USB-C charging device, or power pass-through device. Your system will continue to work, but may not perform at its peak.”
• “Weak charging state, please check power charger.”
• “The AC power adapter wattage and type cannot be determined. The battery may not charge. The system will adjust the performance to match the power available.”
• “The connected AC adapter has a lower wattage than the recommended model – Please connect the AC adapter which was shipped with the system for best system performance”
• “For full performance, connect a higher power adapter”

Despite these warnings, most business and consumer laptops will indeed continue to charge with a lower wattage charger connected, and the messages can often be disabled in your laptop’s BIOS settings.

All this to say that in most use cases, the differences between 60W and higher wattage chargers are minimal, and 60W charging is likely enough to charge most laptops!
 

Plugable SKUs that feature 60W charging: TBT4-HUB3C, USB4-HUB3A, TBT3-UDC1, UD-3900PDZ, UD-6950PDZ, UD-MSTH2, UD-MSTHDC, USBC-PS-60W

Plugable offers a range of high-quality chargers designed to meet diverse charging needs. This article provides an overview of common use cases for our chargers and highlights key features such as Programmable Power Supply (PPS) support and third-party safety testing to UL standards.

Key Features of Plugable Chargers

• Programmable Power Supply (PPS): Some Plugable chargers are equipped with PPS technology, which allows them to dynamically adjust their output for optimal charging speeds and efficiency, ensuring your devices charge quickly and safely.
• Safety: Safety is paramount at Plugable. In addition to rigorous internal testing, our chargers undergo third-party safety testing to meet UL standards. This certification (where applicable) ensures that our products are safe, reliable, and perform as expected.
• Compact and Portable Designs: Plugable chargers are designed with portability in mind, making them perfect for travel or as secondary chargers. Their sleek and compact form factors ensure they fit easily into bags and tight spaces without compromising on power.
• Versatility: Whether you need to charge a laptop, phone, tablet, or multiple devices simultaneously, Plugable offers a charger to meet your needs. Our chargers are compatible with a wide range of devices from various manufacturers, including Apple, Samsung, and Google.

Common Use Cases for Plugable Chargers

USBC-PS-60W: USB-C 60W Power Supply

Use Case #1: Ideal replacement power adapter for most consumer and business laptops including popular systems such as Apple MacBooks, Windows laptops (Dell XPS, HP Spectre, Lenovo ThinkPad), and Chromebooks.

Use Case #2: A worthwhile secondary charger to keep in your laptop bag/backpack.

Use Case #3: Optimal replacement USB-C power source for pairing with portable gaming consoles such as the Nintendo Switch or Steam Deck – either docked or handheld.

Features:

• 60W Power Delivery (PD) for efficient charging.
• Variable 5, 9, 12, 15, and 20V output at up to 3A (60W)
• Compact and portable design.
• Third-party lab tested and certified to meet or exceed UL/IEC 62368-1 standards.

PS-EPR-140C1: USB-C 140W GaN Power Adapter with PD 3.1 EPR

Use Case #1: Perfect for those seeking a smaller, lighter replacement or secondary charger for Apple devices requiring up to 140W. Also works as a great daily driver for consumer, business, and workstation laptops with USB-C or Thunderbolt charging.

Use Case #2: Good for quickly charging laptops, power banks, or other portable devices such as camping gear or educational tools at their maximum charging rate.

Use Case #3: Future-proof charger for upcoming laptops that can charge at rates above 100W through USB-C PD 3.1 Extended Power Range (EPR)

Features:

• 140W Power Delivery (PD) for fast charging.
• EPR and supported voltage ranges: 5V up to 3A (15W), 9V up to 3A (27W), 15V up to 3A (45W), 20V up to 5A (100W), 28V up to 5A (140W)
• Gallium Nitride (GaN) based technology for a power efficient and compact design
• Smaller and lighter (also doesn’t get as hot) design compared to the original Apple charger.
• Charge a 16” MacBook Pro from 0% to 100% in 1 hour 27 minutes.
• Third-party lab tested and certified to meet or exceed UL/IEC 62368-1 standards

PS-30C1W/PS-30C1B: USB-C 30W GaN Power Adapter

Use Case: Excellent travel or replacement charger for phones and tablets including Apple iPhones and iPads, Samsung Galaxy, Google Pixel, Lenovo Tab, and OnePlus devices

Features:

• 30W Power Delivery (PD) for fast charging.
• Available in white (PS-30C1W) and black (PS-30C1B) colors.
• Supported voltages: 5V up to 3A (15W), 9V up to 3A (27W), 12V up to 2.5A (30W), 15V up to 2A (30W), 20V up to 1.5A (30W), PPS 3.3V-11V up to 2.7A
• Gallium Nitride (GaN) based technology for a power efficient and compact design
• PPS support for a wide range of device compatibility.
• Compact design for easy portability.
• Third-party lab tested and certified to meet or exceed UL/IEC 62368-1 standards.

PS-40C2W/PS-40C2B: Dual USB-C 40W Power Adapter 

Use Case #1: Ideal for tight spaces such as behind nightstands or tables, and capable of charging various devices including a wide range of USB-C based mobile devices and even laptops such as MacBooks and Ultrabooks (may take some time depending on make and model).

Use Case #2: Compatible with mobile gaming devices like the Nintendo Switch and Steam Deck, offering a versatile charging solution for gamers. Similar gaming devices (ROG Ally, etc.) should also be compatible with the PS-40C2W/B.

Use Case #3: Use as a compact dual power source for lower-power USB-C devices such as Apple Homepod Mini speakers, Raspberry Pis, portable monitors, USB fans, and wireless charging stations.

Features:

• Dual port design with 40W total output (first device that is plugged in will take priority charging to ensure fast charging).
• Low profile for tight space applications.
• Supports up to 20V
• Available in white (PS-40C2W) and black (PS-40C2B).
• PPS support for efficient charging of multiple devices.
• Third-party lab tested and certified to meet or exceed UL/IEC 62368-1 standards.

PS1-CA1: Wall Power Outlet Extender with USB-A and USB-C Charging Ports

Use Case #1: Perfect for those who need to charge both USB-A and USB-C devices without sacrificing a wall plug.

Use Case #2: A worthwhile addition to a garage or workspace. Powering tools like a drill or saw while charging a Bluetooth speaker or running an air compressor or work light while charging a portable battery pack.

Use Case #3: Functionality for a guest room! Power a bedside lamp or alarm clock while providing guests with a convenient USB charging option for their everyday devices, including wearables such as smartwatches or fitness tracker or audio products such as AirPods or Bluetooth headphones.

Use Case #4: Makes for a great traveling charger with 3 different charging options built-in and the grounding pin helps to secure the charger to wall outlets in hotels

Features:

• Dual port design with USB-A and USB-C compatibility.
• Maintains access to a wall plug while charging devices.
• Compact and convenient for everyday use.
• Supported configurations and voltages:
  • USB-C only 30W max:
    • 5V/3A
    • 9V/2.22A~3A
    • 12V/1.67A~2.5A
    • 15V/2A
  • USB-A Only:
    • 5V/2.4A
  • Note: When USB-C and USB-A are used at the same time, USB-C supports 20W max & USB-A supports 12W max.
• Supports PD and rapidly charges your devices at up to 30W when charging a single USB-C device
• Third-party lab tested and certified to meet or exceed UL/IEC 62368-1 standards.

Plugable Technologies is committed to providing high-quality, reliable chargers that cater to a variety of use cases. With features like PPS support, UL certification, and compact designs, our chargers are designed to meet your everyday charging needs efficiently and safely. For more information or to purchase a Plugable charger, visit our website or contact our support team.

If you have any questions or need further assistance, please feel free to reach out to our support team at support@plugable.com.