I'm using a common charger for both of my laptops.

The charger is specified at 20 Volts and 3.25 Amperes. My other laptop has a specification of 19 V and 3.42 A.

Is it safe to charge my laptop with chargers whose specifications exceed or are not equal to the mentioned specifications?

I have read somewhere that it may cause some damage if the voltage or amperage is not matching the specs.


2 Answers 2


Using a charger with the wrong voltage rating can potentially damage your laptop. This is typically caused by too high voltage. But using a charger with too high current won't damage your laptop. Using a charger with too low current rating might fry the power supply, but not the laptop.

As the difference in voltage in this case is small, it should be OK. But I really doubt that anyone would stick their neck out and guarantee this. I believe it should be OK because your laptop will [most likely] have circuitry in it which will filter and regulate the voltage on-board - it must do this to charge the battery, and 1 volt is not a big deal to most of these kinds of circuits. It's probably not ideal though.

  • 1 V too much is unlikely to damage the laptop, but better do not try it.
    – neverMind9
    Commented Aug 28, 2018 at 10:44
  • Using a charger with too low current rating: If the power supply is unable to keep up with the laptop's demands, the laptop will drain the battery if it has one. If too much power is drawn, the power supply will reduce the output voltage to avoid getting overloaded.
    – neverMind9
    Commented Aug 28, 2018 at 10:46

Use the recommended charger only

I discourage you from using anything else than what came with your respective laptop. It is not recommended to swap chargers for different laptops, even if it's the same brand. This is only 100% safe if it is the same brand and exactly the same laptop model. If you check your laptop manual, there should be at least one paragraph dedicated to explaining the risks of using a different charger. There should also be some mention about what charger models are recommended for your laptop model.

Charging with a power supply

It is possible to charge batteries with an adjustable power supply. But this is something that should be left to the professionals. You can't leave it unattended, as you have to observe the state of charge.

Reference: Charging with a Power Supply

Going Star Trek...

It would be ideal to use a professional, digital, programmable, DC power supply. This type of device is used for equipment testing, and as they are very advanced, precise and programmable, they can be used to charge any laptop you want (and more).

Here is an example of a Tektronix PWS4323:

tektronix psw4323

This is obviously an overkill! It's not something for the average Joe. But for every problem, man has created a solution! Chances are that this little baby costs probably more than your laptop alone. MSRP: $904

  • 1
    dammit, my charger is like 4 times the weight of my laptop Commented Feb 11, 2020 at 19:47
  • 4
    Your advice about not swapping chargers even within the same brand seems unwarranted. A manufacturer will typically ensure their units are interchangeable. If the voltage is the same, and the current the lower supply can handle is more then the laptop needs, and the polarity matches and the power supply is of merchantable quality it will be fine.
    – davidgo
    Commented Mar 6, 2020 at 6:15

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