USB-C PD vs Traditional Barrel Connectors in Desktop Adapters

I just got a Lenovo V14 G3 laptop. It's quite nice, though not top-end. I hate soldered memory but this at least has one SO-DIMM slot, and more importantly, a power button that isn't embedded in the keyboard (especially not between Delete and Backspace like many have). But, it can use USB-C for power, or a dedicated power connector. Obviously that adds to the cost, but then Lenovo included a USB-C power adapter, so that power connector is just unused, but the USB-C port is blocked. I've always considered a dedicated power connector to be better since it doesn't use up the lone USB-C port on many laptops, so it kind of sucks although I doubt I'll really need it. But is there really any benefit to using the USB-C port for power other than standardization, so you could use any USB-C Power Delivery adapter/dock that has enough wattage? (The power connector is one of those teeny-tiny ones that have little strength to them, so it's a little better in that respect.)

And if I'm at home I don't care about the USB-C port being blocked

Well, what if you need to use a USB-C device? Assuming you don't have other free ports and adapters. Why would being away from home make you need it available?

The only time I ran a cropper

What is "a cropper"?

It's unsurprising that some brands and models would have an arbitrary requirement to use THEIR charger rather than any PD charger regardless of capability, giving vague reasons like "safety", to require you to pay more for theirs, or only use a brand that has paid a fee to have a compatible chip installed.

But it all still boils down to convenience of having a single charger that works with multiple devices, which I understand, but a small charger and cable for a isn't a lot of extra stuff to carry if I've got a regular power brick in my bag for the laptop, and I wouldn't want to unplug the laptop to charge the anyway. (And with just a cable I could charge the from the laptop.) For me personally, it's not a big thing, but I understand for other people it might be. For my use, it feels like a dedicated charger that leaves the USB-C port free would be better.

Well, what if you need to use a USB-C device? Assuming you don't have other free ports and adapters. Why would being away from home make you need it available?

At least for me, if I'm at home my laptop is plugged into a Thunderbolt / USB-C dock that does all that and more. Whereas when I'm travelling, if I need an adapter for say an HDMI port, etc, I'm more likely to need that port free. But most (i.e. all the ones I'd consider buying) of the adapters that add decent functionality have a passthrough for power anyways, so it's not an issue. You plug the adapter into the USB-C port, the power in to the Adapter and you're good to go.

but a small charger and cable for a isn't a lot of extra stuff to carry if I've got a regular power brick in my bag for the laptop, and I wouldn't want to unplug the laptop to charge the anyway.

Here's an example:

I, in my briefcase, pack 2 USB-C cables and one of these:



The reason I've included this particular picture, is that the max charger is generally on the smaller side when it comes to laptop power bricks. My Lenovo power brick, on the other hand, is bigger than the Mac charger pictured, has both a power cable and a USB-C side cable, and is generally an unwieldy mess of cable and power. Whereas the charger pictured can charge my laptop, and my , at the same time, in a space that is less than a quarter of just the brick, not counting all the extra cable and associated miscellanea that's required.

To each their own, but this has made a significant positive impact in my carryon travel.

Edit for grammar.

At least for me, if I'm at home my laptop is plugged into a Thunderbolt / USB-C dock that does all that and more. Whereas when I'm travelling, if I need an adapter for say an HDMI port, etc, I'm more likely to need that port free. But most (i.e. all the ones I'd consider buy) of the adapters that add decent functionality have a passthrough for power anyways, so it's not an issue. You plug the adapter into the USB-C port, the power in to the Adapter and you're good to go.



Here's an example:

I, in my briefcase, pack 2 USB-C cables and one of these:

View attachment

The reason I've included this particular charger, is that the max charger is generally on the smaller side when it comes to laptop power bricks. My Lenovo power brick, on the other hand, is bigger than the Mac charger pictured, has both a power cable and a USB-C side cable, and is generally an unwieldy mess of cable and power. Whereas the charger pictured can charge my laptop, and my , at the same time, in a space that is less than a quarter of just the brick, not counting all the extra cable and associated miscellanea that's required.

To each their own, but this has made a significant positive impact in my carryon travel.

Yup, the couple of laptops I've had that needed a dedicated power brick, the brick was 2-3x the size of my little USB-C charger that can do both. I don't travel for work as much anymore, but it was a glorious day when I ditched the brick and just carried a charger the size of 2 boxes of matches You have options. You could use the barrel connector if you wanted, but that's proprietary and Lenovo's going to charge whatever they feel like for a replacement. Laptops that move around either benefit from small chargers being packed in your bag (as noted, GAN chargers are very small and light) and/or from having a charger everyplace you'd like to plug in your laptop. Home + work is a common scenario. If you were stuck with proprietary Lenovo barrel connector power only, you'd be on the hook to buy one extra proprietary power brick that couldn't be used with any other laptop for the 2nd location. With USB-PD, you can just use whatever charger you have and there are plenty that have multiple plugs so charging your or whatever else at the same time is a non-issue where barrel connector power does not give that advantage.

If you have a docking unit, the majority have passthrough PD and the majority of laptops support power extension so you don't block the port. On a laptop with nothing but say 2 USB-C connectors, you're gonna probably need a port expander/docking station anyway and they're cheap-- and sometimes packed in with more expensive laptops.

Being beholden to using only barrel-connector/proprietary power is also an e-waste problem. You're probably only going to ever be able to use that brick with that model of laptop. Big corps can work around that to some degree, but eventually some of them will be thrown away while still able to function. USB-C chargers mostly only get thrown away if they fail since they can always charge something else.

There are still plenty of use cases in very high power consumption laptops where they can't use USB-C or trying to use USB-C forces the computer into low-performance mode if you try to run them with USB-C power only. I have a bunch of 330w power adapters that probably weigh about 800-900g each that are super not-portable and ~$100 each if you want one extra so you don't have to lug them around, but they're for laptops that need that much power. When the day arrives that I can stop buying proprietary power connectors forever and just use USB-C, that's going to be a good day.

Being beholden to using only barrel-connector/proprietary power is also an e-waste problem. You're probably only going to ever be able to use that brick with that model of laptop. Big corps can work around that to some degree, but eventually some of them will be thrown away while still able to function. USB-C chargers mostly only get thrown away if they fail since they can always charge something else.

To jump on this, the opposite problem:

If you have an old discontinued laptop and the power brick breaks or the cord/connector wears out on the proprietary barrel connector: good luck finding a replacement.

If your laptop uses USB-C, just get a new USB-C charger from anywhere. Corner drug stores and airport shops even sell them. Convivence. So example. Most Dell laptop power supplies have been 19.5V 3.34A for the last two decades. Being DC barrel plugs with Data pin. The have two sizes and even have kept the same data interface so you can use converters to different barrel plugs. Which brings that with the USB-PD spec being 20V/3A or 20V/5A The 20V/3A normally gets used because it was so close to the old standard power profile they designed all their systems on. So slowly they are moving on.

Now why Lenovo decided to give you only one USB port is all on Lenovo. But Dell on the other hand will make sure to have more than one if it is using USB C, along with proper USB dongle spacing.

Or when your kid loses the power brick to their school laptop, and tries to get out of doing their homework... just plug that bad boy into a USB connector and they have no excuse.

In this case, the laptop takes both, so I could easily get a USB-C charger from something else (assuming there are other devices in the house using chargers with that much output, which there aren't). The USB-C still comes down to just a convenience, while the dedicated port avoids having to share a port and lose access to it unless I carry around a big dock.

I understand there are advantages like convenience of sharing a power source, using a standard connector for all, but that's about it. I don't see any other benefits. And the disadvantage is that most laptops still only have one USB-C port, which gets taken up by a charger that you will often have connected (whether you're at home or not), and some laptops can't even run at full speed unless they use specific chargers or docks which reduces that "standardization" advantage.

I was just looking for OTHER benefits to using a USB-C charger that would make it preferable over my personal priority for having that USB-C port accessible without needing to connect a docking station. I'm still glad that I'd have the OPTION of using either one in case the proprietary charger failed. At least until all laptops have two or more USB-C ports which might still be a while on the lower end.

Lenovo hasn't even updated their compatibility information for their chargers to include this model of laptop, even though both the USB-C and barrel connector models are listed in the "accessories" on their site for this laptop. It's $60 from them, but can be obtained from Amazon for $20. (Though it's not clear if they're actually Lenovo-brand or not. They have the logo on the label, but...) I was thinking it would be nice if I could just adapt the USB-C to the barrel connector, but I know that's not just a matter of converting the shape and would require electronics and power management in the adapter, making it somewhat expensive. But, if a new charger is $20 or even $60, then $20 or $30 for a small adapter that would allow the use of basically any power source would not be that bad. But it would be nice not to have to buy a kit of 30 tips and daisy chain connectors (making it stick out even further from the laptop). It's too niche of a need for them to produce a separate adapter for every possible model, though.

In this case, the laptop takes both, so I could easily get a USB-C charger from something else (assuming there are other devices in the house using chargers with that much output, which there aren't). The USB-C still comes down to just a convenience, while the dedicated port avoids having to share a port and lose access to it unless I carry around a big dock.

Ultimately, Lenovo or whomever should just add an additional USB-C port. They're choosing to use that real estate for the proprietary connector. They could have chosen to not do that, and instead used that real estate for something else and made sure they had sufficient USB-C connectors.
Even Apple puts 2 USB-C connectors on their laptops, except for that stupid 12" MBP from like , they've generally gotten that part right even when removing all sorts of useful ports.

You do realize how small USB-C docks are, right? They're not bulky, most being about 3" long with a short pigtail USB-C cord. Models with Ethernet sometimes are a little bigger and more expensive, but you don't need to get that option.

Ultimately, Lenovo or whomever should just add an additional USB-C port. They're choosing to use that real estate for the proprietary connector. They could have chosen to not do that, and instead used that real estate for something else and made sure they had sufficient USB-C connectors.
Even Apple puts 2 USB-C connectors on their laptops, except for that stupid 12" MBP from like , they've generally gotten that part right even when removing all sorts of useful ports.

You do realize how small USB-C docks are, right? They're not bulky, most being about 3" long with a short pigtail USB-C cord. Models with Ethernet sometimes are a little bigger and more expensive, but you don't need to get that option.

An additional USB-C port would undoubtedly add cost to the laptop compared to a dedicated power connector. Manufacturers are always looking to save every penny on the low end of devices, because they're not able to charge a premium with higher margin. There are inexpensive models with two USB-C ports, but those are low end and they ONLY have those two ports so you only end up with one for data/devices (Chromebooks that aren't expected to DO much anyway). There are PC laptops with more ports including more than one USB-C port, but they're upper mid-range and then you're looking at $500 for even a refurb unit, or making concessions in other areas.

Apple puts ONLY USB-C ports on their laptops and has for years, and on some models it's only 2 of them and one of them gets used up for power. Apple is an entirely different market from Windows PCs - they can just make wholesale changes because there is no alternate source, no competition if you want MacOS. You either take what they give you or you don't get a Mac.

A 3" dock is still larger than just having an extra USB-C port, or something even more basic that just provides that one extra port. And there are multiple people in this thread that think carrying a little charger in their bag is a crippling amount of extra mass.

USB-C Power Delivery - A Brief Review

USB-C Power Delivery (PD) allows for the efficient and flexible transfer of power between devices via a USB-C connection. Unlike traditional USB ports, USB-C ports with Power Delivery can deliver higher power levels. This makes them ideal for charging various devices, including laptops, smartphones, and other peripherals.

Initially announced in , USB-C Power Delivery was designed to provide up to 100W of power to charge various devices, including laptops. It wasn’t until when the USB Power Delivery promoter group introduced USB-C Power Delivery revision 3.1 which added Extended Power Range (EPR) mode which supports higher voltages, and up to 240W of power!

The introduction of EPR is relatively recent, and by extension, there aren’t many docking stations or laptops on the market that have implemented this newer standard. As a result of the original 100W upper limit, most universal USB-C and Thunderbolt docking stations on the market do not provide more than 100W to charge laptops.

The Rising Power Demands

Many modern laptops designed to handle resource-intensive tasks that demand substantial computing power may require a high amount of power to charge when performing those tasks. While docking stations can often be a necessity for expanding connectivity options, they may not always provide the necessary charge to meet the demands of power-hungry laptops operating at full load - this is explored in more detail in another of our blog posts: https://plugable.com/blogs/news/are-usb-c-and-thunderbolt-docking-stations-able-to-charge-my-gaming-laptop 

Some laptops may not support charging over USB-C at all and instead use a charger with a barrel-style connector.

This situation introduces an interesting question for these laptops: what do you do when you need to connect your laptop to a desk’s worth of peripherals and charge simultaneously?

Luckily, the solution to this problem is as simple as it is intuitive - you can connect your laptop’s charger and a USB-C dock with power delivery simultaneously. This will allow your power-hungry computer to receive adequate charge and connect your displays and peripherals through a dock all at once. 

Safety in Symbiosis

We’re commonly asked if using a laptop’s power adapter at the same time as a docking station with power delivery introduces the risk of damaging the laptop, and we’re happy to say that it is generally totally safe to do this.

One of the features of USB-C power delivery is that it dynamically adjusts the amount of power provided to the laptop, so only the amount requested by the computer is given at any time. This can even go to the extreme of the charger completely halting the flow of power to the computer if the computer doesn’t ask for it.

This process is an intelligent negotiation between the computer and the power adapter. We go into more detail on this process in a video on our YouTube channel: https://www.youtube.com/watch?v=8-ZlLYBjfhA

When two power adapters are connected to a computer simultaneously, the computer prioritizes one power adapter over another. Usually, the laptop prioritizes whichever charger can provide more power, but this may differ depending on the implementation by the laptop manufacturer. This prioritization often results in the power adapter providing charge to the computer while the docking station does not.

For example, this is the System Report of a MacBook Pro (M2 Pro, ) when the MacBook’s included 67W charger is connected simultaneously as a UD-PDZ, which provides up to 60W of power over USB-C. 

Conclusion

Support for USB-C Power Delivery’s Extended Power Range (EPR) in docking stations hasn’t hit the mainstream yet. As a result, some computers require more than 100W, the original upper limit of USB-C Power Delivery. To charge those computers and connect all of the peripherals a dock allows, it may be necessary to connect the dock and the laptop’s power adapter simultaneously.

USB-C Power Delivery’s characteristic of dynamically negotiating the power provided to a laptop makes connecting a laptop’s power adapter simultaneously with a docking station a perfectly safe option for charging and docking a computer whose power needs exceed what a dock can provide. 

Are you using your laptop’s power supply to charge your laptop along with a docking station? Feel free to leave any questions or comments below, and we’re glad to speak more about charging behavior.