Laptop PSUs - I just don't get it!

[The Elf]

Recently I purchased an LG Gram laptop. It came with a 90W 'Fast Charger' PSU (connects via USB-C).

Today I plugged in a 130W Dell PSU as I worked, and the battery has run down, since the laptop says it is not getting enough power from the PSU.

I don't get it!

Trying to find an additional PSU for this laptop is proving impossible. I'm seeing so many specs and numbers my head is spinning! None of the options I've seen mention 'fast charger'.

In short, what do I need to buy to have a second PSU for this laptop that will not end up with the battery draining?

[DGL.]

It's interesting that it doesn't like it, my 2017 Lenovo can charge from either the proprietary Lenovo supply/connector or USB-C, Windows does complain that it is not charging and to use the correct PSU but it's actually lying and charges just fine from either a generic Delta 65W USB-C charger (identical to one shipped with a MSI laptop) or one from a Nintendo Switch.

[Matt Houghton]

I can't see from that pic due to the resolution, but is there perchance a part number written upon it? (Is that what is near P/N towards the bottom?) If you can't find the spec you need on the device itself, I'd stick that along with LG Gram into Google and see what it throws up. (I'm assuming that QR code doesn't take you anywhere useful?)

[tea for two]

In time honoured SoS fashion we require more info : such a rookie.

Recently I purchased an LG Gram laptop. It came with a 90W 'Fast Charger' PSU (connects via USB-C).

Today I plugged in a 130W Dell PSU as I worked,

What's the exact model for LG charger and Dell charger.
The LG charger looks like LP90DGC20H-WW outputs 20V 4.5A max for 90W max.

The Dell charger should be able to output this from a single usbC cable. The V, A, and W numbers on the Dell charger will tell us.
If the Dell charger can't output 20V 4.5A 90W that could be the issue.

When I had a similar issue with my Asus laptop charging via usbC port, it was the usbC cable that couldn't deliver the required Wattage. I had to get a usbC Iniu 100W rated usbC charging cable that did the trick. Before this I had to get a usbC charger that outputted the required V, A,W for my Asus.

[The Elf]

I can't see from that pic due to the resolution, but is there perchance a part number written upon it? (Is that what is near P/N towards the bottom?) If you can't find the spec you need on the device itself, I'd stick that along with LG Gram into Google and see what it throws up. (I'm assuming that QR code doesn't take you anywhere useful?)

The QR code doesn't generate a link, despite all my efforts. The part number (EAY65915332) doesn't bring up anything as LG.

I've tried all the obvious searches, even digging around on LG site for an hour, but I can't find anything. I thought it would be simple to order a spare PSU - I've done it with every other laptop I've ever owned.

Best I can do for a detailed pic:

[The Elf]

When I had a similar issue with my Asus laptop charging via usbC port, it was the usbC cable that couldn't deliver the required Wattage. I had to get a usbC Iniu 100W rated usbC charging cable that did the trick. Before this I had to get a usbC charger that outputted the required V, A,W for my Asus.

The Dell charger has a captive cable, so must be up to the job.

Here's the best shot I can muster:

[Wonks]

If you stick LG before the part number when searching you get a few results in the US, but all over $100.

It’s a multi-voltage PSU, with several different voltages and corresponding power outputs, so I assume that there is some form of handshaking going on that selects the correct voltage for the connected item.

I expect that the Dell charger is either providing the wrong voltage or the laptop isn’t seeing the correct handshake and so not turning on the charging circuit.

[Hugh Robjohns]

I think this is the original unit:

https://www.chargerlab.com/lg-introduce ... f-devices/

MODEL: LP90DG20H-WW
Part No: EAY65915322

It appears to be a smart power supply offering a range of fixed output voltages and currents according to the Power Delivery (PD) format. However, it also includes a negotiable supply voltage for the receiving device over USB-C using the newer (and less common) PPS* format:

Output: USB-C, supports PD and PPS
PD Output: 5V/3A, 9V/3A, 15V/3A, 20V/4.5A
PPS Output: 5V-20V

I'm guessing the reason your alternative supply doesn't charge the battery is because it's not a PPS type able to negotiate with the laptop to provide the required voltage.

*PPS = Programmable Power Supply — this is an optional subset of the PD format. A USB-C PD supply provides fixed 5, 9, 15 and 20V supplies.

A PPS supply allows anything between 5 and 20V, depending on what the destination asks for, and is increasingly required for the best charging of lithium batteries.

The idea is to avoid the need for complex DC-DC conversion in the laptop, tablet or phone. Instead, that job is offloaded to the external psu, along with all the heat...

This 100W fast charger claims to support PPS and might be a viable spare:

100W USB C Plug, Anker Prime GaN 3-Port Fast PPS USB C Charger, Compact and Foldable Design, For MacBook Pro/Air, iPad Pro, iPhone 16/15 Pro, Galaxy S23/S22, Note20, Pixel, Apple Watch, and More https://amzn.eu/d/eKjbnK1

[tea for two]

The LG charger looks like LP90DGC20H-WW

An important necessary spec is the PPS on this LG charger : PPS is written inside brackets just after 20V 4.5A 90W.
PPS Programmable Power Supply is an important addition to standard PD Power Delivery of usbC chargers.

Best I can do for a detailed pic:

::

Here's the best shot I can muster:

This Dell charger doesn't have PPS.
Searching online PPS 100W usbC charger throws up a few.
There's a 35squid Voltme USB C GaN 100W Charger PPS Quick Charge.
Also the Anker Prime 100W USB C Plug, Anker Prime GaN 3-Port Fast PPS USB C Charger Hugh linked to.
I'd go for the Anker.

Also using the usbC cable that was with the LG charger and or acquiring usbC cable stated delivery 100W or 120W or even 240W.

[The Elf]

Thanks for all this, guys.

So we've reached a point where we have 'smart' PSUs such that, despite having a 'dumb' PSU with plenty of capability to power a device, won't work.

And the batch of USB-C PSUs I bought last year are now redundant.

You couldn't make this stuff up...

I'm eyeing this:
https://www.amazon.co.uk/FINIBO-440W-US ... =8-22&th=1

The form factor suits me better ('normal' plug at the far end), and it seems flexible enough for future requirements. Can I hit the 'purchase' button?

[DGL.]

I would only buy one from a well known reputable manufacturer, some company who's name seems to be random letters, not for me thank you!
Your laptop would have been a decent amount of dosh so there's no sense in buying something that's not from a decent brand. Noting that Anker are a decent manufacturer.

The OEM PSU was probably made by Delta, FSP or LiteON and as such you'll probably find a suitable one made by them.

[tea for two]

I'm eyeing this:
https://www.amazon.co.uk/FINIBO-440W-US ... =8-22&th=1

The form factor suits me better ('normal' plug at the far end), and it seems flexible enough for future requirements. Can I hit the 'purchase' button?

It looks like it's trying to do too much at a cheap price, it's same price on auction site : although it has over 100 positive reviews on zon. For myself I wouldn't get it could be flakey could be alright, it could heat up a lot who knows.

I'd go for a known brand as Anker, the one Hugh linked to isn't trying to do too much.

[The Elf]

I really want to avoid that huge plug form factor.

Can anyone point me to a suitable alternative?

[Folderol]

It looks as if it just chucks out a variety of fixed voltage outputs, so I very much doubt it does any negotiating at all - very risky

[Wonks]

I really want to avoid that huge plug form factor.

‘Huge’, when the one you liked had a giant rectangle attached?

You’re weird!

[Wonks]

It looks as if it just chucks out a variety of fixed voltage outputs, so I very much doubt it does any negotiating at all - very risky

The two top 100W ports are PPS, so should provide variable voltage/currents and comms.

[Folderol]

It looks as if it just chucks out a variety of fixed voltage outputs, so I very much doubt it does any negotiating at all - very risky

The two top 100W ports are PPS, so should provide variable voltage/currents and comms.

Ahh! Didn't notice that - blame it on elderly failing eyesight

[Drew Stephenson]

I think this may do the job but it doesn't actually say it's a PPS anywhere in the specs
https://www.amazon.co.uk/Belkin-Fast-Ch ... eature_div

[tea for two]

Can anyone point me to a suitable alternative?

Searching online PPS 100W usbC charger throws up a few.
There's a 35squid Voltme USB C GaN 100W Charger PPS Quick Charge.
Also the Anker Prime 100W USB C Plug, Anker Prime GaN 3-Port Fast PPS USB C Charger Hugh linked to.
I'd go for the Anker.

Also using the usbC cable that was with the LG charger and or acquiring usbC cable stated delivery 100W or 120W or even 240W.

https://amzn.eu/d/eKjbnK1

I really want to avoid that huge plug form factor.

This Anker PPS is smaller.

::

100W rated usbC cable I been using an Iniu 100W rated usbC cable aboot a year.

[The Elf]

I really want to avoid that huge plug form factor.

‘Huge’, when the one you liked had a giant rectangle attached?

You’re weird!

But the plug is a normal plug at the end of a cable. The box in the middle is less of a problem to ne. I want to avoid a huge plug at the plug end!

[The Elf]

I think this may do the job but it doesn't actually say it's a PPS anywhere in the specs
https://www.amazon.co.uk/Belkin-Fast-Ch ... eature_div

Looks good in all ways, except no guarantees it would work.

[Wonks]

If it doesn’t say PPS, then avoid.

[illegal colors]

And the batch of USB-C PSUs I bought last year are now redundant.

Try what you already have. You don’t need 90W to keep your battery from discharging. Try 65W or 20W. The newest smart devices often negotiate better terms with older chargers than with the latest and greatest from another manufacturer.

[Drew Stephenson]

I think this may do the job but it doesn't actually say it's a PPS anywhere in the specs
https://www.amazon.co.uk/Belkin-Fast-Ch ... eature_div

Looks good in all ways, except no guarantees it would work.

Looking at their website it would appear that GaN is the new angle on PPS (trying to cut through the chemistry/technobabble) - a quick search isn't throwing up any GaN chargers that aren't PPS.
Try it any see, it won't cost much for return postage.

[Hugh Robjohns]

GaN is just a semiconductor technology that produces less heat, making it useful in chargers (and LEDs)... but using GaN doesn't guarantee PPS compatibility.

The Belkin website lists these chargers as PPS compatible (and I dont think it includes the one you found):

https://www.belkin.com/uk/products/char ... rt=0&sz=24