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I own a Acer laptop from 2017, which came with a brick-sized 19V/3,42A power supply that's connected via a 5.5/2.5mm DC plug. Although the laptop features a USB-C port, it unfortunately doesn't feature a charging capability.

Since I own a USB-C PD 65W charger, I was wondering if it is possible to buy one of the various USB-C-to-DC-plug adapters and charge it that way? Or are there any pitfalls involved such as potentially damaging the laptop?

Here's a example link to a random adapter that has '19V PD' printed on itself. Most of these state that they feature a 'emulator trigger', others mention a 'analog charging output'

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  • Unless you don't need the laptop anymore, I wouldn't try to experiment with charging. Make sure to replace the power supply with an exact copy (and not one where you can change the polarity).
    – Gerard H. Pille
    Commented Jan 27, 2021 at 16:47
  • What is the goal? Replace a lost or damaged power supply? Have a spare on hand? Or, be able to use smaller and lighter USB-C chargers? There are USB-C adapters for older laptops, I know Lenovo makes them for their laptops. I'd only buy such an adapter from a well known manufacturer as something that screws this up can be a fire hazard. When they work they are great, when they don't it can be very expensive. Choose your adapter widely, you could get burned. Literally.
    – MacGuffin
    Commented Jun 28, 2021 at 8:13
  • I've asked this same question to Tuxedo customer support. They replied that it is important to respect the specified electric tension precisely, and 20V is not good if the intended tension is 19V. They however also said: "Where it doesn't necessarily matter is the Ampere number. But here too, it would be better to stick to the specifications if possible, or if this is not possible, then look for a charger that can output exactly 19V and a little more amps than the original power supply."
    – Alexey
    Commented Feb 27 at 13:51

2 Answers 2

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"It depends" is about the best you are going to get.

It depends entirely on what the PD charger can put out, how intelligent the adaptor is to be able to select the right output from the PD charger and how tolerant the laptop is of "random" adaptors. Some laptops expect just a dumb power supply, others expect some simple communication or power select method.

A laptop expecting 12V might not like receiving 15 or 20 from an adaptor that is configured wrongly, or simply might not work if the adaptor fails to negotiate with the PD charger and received only 5V. 5V is all that a PD charger will put out if the USB device being plugged in fails to communicate. It might put out 9V if it thinks there is a fast charging phone, but don't count on it.

A tiny microcontroller could in theory talk to the PD charger to select 12V, 15V or 20V if available, so maybe an intelligent adaptor that knows what the laptop expects could work.

It's not down to the laptop to tell the PD charger what it wants, it's down to the $0.50 piece of plastic between your charger and your laptop and just how much faith you have in the old adage "you get what you paid for".

It depends.

If you want to use your USB C charger with confidence then you need a laptop that supports USB C charging.

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    You can get small USB-PD power boards with a button to cycle between the available voltages. In the same way though you can get ones for a specific voltage, so if the laptop needs 20 then you can get a 20v usb-pd adapter and theoretically it should be fine. This also assumes there's no communication or handshaking done between the laptop and the power source - a lot of the time this is done on the 3rd pin on a normal barrel style jack, so OP might have to make provisions for this also (in some cases it's as simple as putting a resistance between vcc/gnd and the 3rd comms pin...)
    – QuickishFM
    Commented Jan 27, 2021 at 18:52
  • I agree with the buyer beware warning. 19VDC power supplies for laptops are quite common and most any big box store will likely have one on the shelf or can order one for you quickly. A $10 adapter is a gamble while a proper power brick will cost $20 to $30 and be no gamble at all.
    – MacGuffin
    Commented Jun 28, 2021 at 7:58
  • Even if the RMS voltage output is exactly to spec (19V), the power condition could still be terrible (very noisy voltage output, power draw could damage the USB-C charger etc).
    – Aron
    Commented Sep 22, 2022 at 4:34
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It won't "just work". USB chargers will provide 5V power unless there's some circuitry that will negotiate higher voltage.

I'm quite sure that requesting 20V from a USB-PD compatible charger would work fine to power that laptop and within its design tolerances, but I'm not aware of such a product.

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