GVGT: When USB (GAN) Charger Marketing Claims Are Technically True

[hwzlite]

https://hackaday.com/2025/10/03/when-usb-charger-marketing-claims-are-technically-true/

We have seen many scam USB chargers appear over the years, with a number of them being enthusiastically ripped apart and analyzed by fairly tame electrical engineers. Often these are obvious scams with clear fire risks, massively overstated claims and/or electrocution hazards. This is where the “600W” multi-port USB charger from AliExpress that [Denki Otaku] looked at is so fascinating, as despite only outputting 170 Watt before cutting out, it’s technically not lying in its marketing and generally well-engineered.

The trick being that the “600W” is effectively just the model name, even if you could mistake it for the summed up output power as listed on the ports. The claimed GaN components are also there, with all three claimed parts counted and present in the main power conversion stages, along with the expected efficiency gains.

While testing USB-PD voltages and current on the USB-C ports, the supported USB-PD EPR wattage and voltages significantly reduce when you start using ports, indicating that they’re clearly being shared, but this is all listed on the product page.

The main PCB of the unit generates the 28 VDC that’s also the maximum voltage that the USB-C ports can output, with lower voltages generated as needed. On the PCB with the USB ports we find the step-down converters for this, as well as the USB-PD and other USB charging control chips. With only a limited number of these to go around, the controller will change the current per port dynamically as the load increases, as you would expect.

Considering that this particular charger can be bought for around $30, is up-front about the limitations and uses GaN, while a genuine 300 Watt charger from a brand like Anker goes for $140+, it leads one to question the expectations of the buyer more than anything. While not an outright scam like those outrageous $20 ‘2 TB’ SSDs, it does seem to prey on people who have little technical understanding of what crazy amounts of cash you’d have to spend for a genuine 600 Watt GaN multi-port USB charger, never mind how big such a unit would be.

Ref: https://shopee.sg/search?keyword=600w gan charger

 

[windwaver]

Hey guys, I see some really cheap (below SGD$10) 120W to 200W GAN chargers, are they even legit?

 

[windwaver]

I use Ugreen, Vention, Baseus and the usual stock fast chargers from Samsung and Xiaomi so I'm skeptical about those high wattage GAN chargers below $10.

 

[Jurong640]

if it's below $10 it's too good to be true, just like those 2TB hard disk for only $10 to $20.

GaN chargers are usually $30 to $60. Never too expensive or way too cheap

 

[windwaver]

if it's below $10 it's too good to be true, just like those 2TB hard disk for only $10 to $20.

GaN chargers are usually $30 to $60. Never too expensive or way too cheap

Yeah.

I'm thinking of buying a 100W UGREEN 4 port charger for office use, it's about $40 now, can buy?

 

[windwaver]

Or another UGREEN 65W 3 port charger for $22

 

[hwsstx]

What Wattage to look for in GaN Charger for charging Note Book?

 

[swathe]

My Anker 45W nano charger charge to 100% faster than UGreen 65W Gan charger.

Says about quality when people previously complained Anker is also a China brand but charge so expensive.

 

[sibeiTrolled]

Hey guys, I see some really cheap (below SGD$10) 120W to 200W GAN chargers, are they even legit?

Legit as in they can charge, Yes.
Legit as in if they truly can support 120W to 200W, NO

Maybe can also give you fireworks in the process

Ugreen, Vention, Baseus and the usual stock fast chargers from Samsung and Xiaomi

Just stick to these brands, they got a reputation to uphold, which in turn makes them try to avoid extreme cost savings.

UGREEN 65W 3 port charger for $22

Do you need to charge your phone as well?
if you do, your 65w will become 45w + 15w or something like that, if that is enough, then good for it
Look at the invidiual maxium port watt as well as what happens when you use 2 or 3 ports.

What Wattage to look for in GaN Charger for charging Note Book?

Standard office laptop like lenovo can only require 40-45w even though the charging brick that comes with it may say 65w.

IMO,
Cost saving - stay with reputable brands 60 / 65w with maybe 2 usb port (A + C or C + C )
"Future proof" - 100W / 120W with at least 3 ports

Please try to read the specifications, it wuld look something like this. This is the GAN charger that i am using

USB-C1 Output: 3.3-21V 5A or 5V 3A or 9V 3A or 12V 3A or 15V 3A or 20V 5A(100W max)
USB-C2 Output: 3.3-21V 5A or 5V 3A or 9V 3A or 12V 3A or 15V 3A or 20V 5A(100W max)
USB-A Output: 4.5V 5A or 5V 4.5A or 5V 3A or 9V 3A or 12V 2.5A or 20V 1.5A(30W max)
USB-C1+USB-C2: 65W+35W
USB-C1+USB-A: 65W+30W
USB-C2+USB-A: 65W+30W
USB-C1+USB-C2+USB-A : 45W+35W+18W

 

[hwsstx]

I'm also looking at Mcdodo GaN Charger - anyone with experience with this brand?

 

[Humster]

All the dunno what W charger need see the specs. Like

Legit as in they can charge, Yes.
Legit as in if they truly can support 120W to 200W, NO

Maybe can also give you fireworks in the process

Just stick to these brands, they got a reputation to uphold, which in turn makes them try to avoid extreme cost savings.


Do you need to charge your phone as well?
if you do, your 65w will become 45w + 15w or something like that, if that is enough, then good for it
Look at the invidiual maxium port watt as well as what happens when you use 2 or 3 ports.


Standard office laptop like lenovo can only require 40-45w even though the charging brick that comes with it may say 65w.

IMO,
Cost saving - stay with reputable brands 60 / 65w with maybe 2 usb port (A + C or C + C )
"Future proof" - 100W / 120W with at least 3 ports

Please try to read the specifications, it wuld look something like this. This is the GAN charger that i am using

USB-C1 Output: 3.3-21V 5A or 5V 3A or 9V 3A or 12V 3A or 15V 3A or 20V 5A(100W max)
USB-C2 Output: 3.3-21V 5A or 5V 3A or 9V 3A or 12V 3A or 15V 3A or 20V 5A(100W max)
USB-A Output: 4.5V 5A or 5V 4.5A or 5V 3A or 9V 3A or 12V 2.5A or 20V 1.5A(30W max)
USB-C1+USB-C2: 65W+35W
USB-C1+USB-A: 65W+30W
USB-C2+USB-A: 65W+30W
USB-C1+USB-C2+USB-A : 45W+35W+18W

If it says 100w only true if you can get 100w with 1 cable output.
Most funny brands 100w is basically like 25W x4 output only.

 

[hwsstx]

All the dunno what W charger need see the specs. Like

If it says 100w only true if you can get 100w with 1 cable output.
Most funny brands 100w is basically like 25W x4 output only.

If it says 100w only true if you can get 100w with 1 cable output.
Are you saying a reputable brand 100W charger, user will not get 100W from each output?...which is the same as:
Most funny brands 100w is basically like 25W x4 output only. ?

...or is both your statements for funny brand?

 

[-Synchronicity-]

If it says 100w only true if you can get 100w with 1 cable output.
Are you saying a reputable brand 100W charger, user will not get 100W from each output?...which is the same as:
Most funny brands 100w is basically like 25W x4 output only. ?

...or is both your statements for funny brand?

The advertised charging output is usually only for a specific port on one cable. When using multi ports generally, the output will be split. The major brands will specify the possible configuration. E.g. 3 port 65w charger, use first port only is 65w, use first and 2nd port is 45w + 15w etc.

For no name brands, they probably won't inform you of the possible configurations. Furthermore, their output for each port is generally shared. E.g. 3 port 65w charger, first port only 22.5w, using first and 2nd port 22.5w + 22.5w.

 

[NightRaven49]

I'm also looking at Mcdodo GaN Charger - anyone with experience with this brand?

bought a 65w gan charger from them almost 5 years ago now, served me well for 3 years before i started trying out other chargers and it became my spare charger. only thing is maybe there is a bit of coil whine under certain scenarios but all of my devices are still alive today also broke the plastic earth pin when i dropped it but superglued back.

 

[pawn_king]

on my 2nd prolink 65w gan charger (misplaced first one).

feels quality, cool to touch when charging, supplied with all travel adapters.
price comparable to ugreen when on discount. $18+ today.
1 Port : Max 65W
2 Ports : Max 63W (45W + 18W)

support local!