Can Using the Wrong Charger Damage My Device?

Yes. No. Maybe.

This is an almost unanswerable question. There are so many chargers and devices with so many characteristics and levels of quality that I can’t give you a reliable answer.

What I can do is offer some guidelines. Some combinations are pretty much guaranteed to work just fine, and some put you at a higher risk of failure.

And, of course, there are some scenarios in which we just don’t know what might happen.

Charger damage

USB-based chargers and devices are unlikely to damage anything no matter what you connect. Outside USB, focus on matching polarity and voltage accurately. Mismatched polarity can easily cause damage. Voltage mismatches also risk failure. Amperage poses less concern as long as it’s equal to or greater than the device’s requirement.

USB is your friend

If the charger and device you’re looking at are based on USB, then there’s not much to worry about. It’s extremely unlikely any USB-based charger will damage a USB-based device.

More often than not, it’ll just work. That’s one beauty of USB.

At one extreme, if your charger is more powerful than your device, the device will just charge or run normally. The charger might be overkill, but it won’t harm anything.

At the other extreme, if the charger is underpowered compared to the device, then the device might:

• Charge or run more slowly.
• Not charge at all (running will continue to drain the battery, though perhaps more slowly).
• Complain. “Complaining” happens with laptops that use USB-C as their power and charging source. For example, if you take your phone’s small USB charger and attempt to use it with your laptop, the laptop may complain that there’s not enough power.

But with USB, damage isn’t likely at all no matter what you do.

Polarity matters most

Once we step away from USB connections, we face a wide range of connections with different shapes, sizes, and characteristics.

The single most important characteristic is polarity. Of the two wires in the charging cable, one is positive and one is negative. It’s very similar to your car: the battery has a positive and negative connection. Connect things backwards, and in your car, you could see fireworks and be looking at a costly repair.

Sparks and flames are rare when computer chargers are connected improperly, but damage is not. Perhaps the fastest and most likely way to damage a device is to connect it to a power supply or charger with the wrong polarity.

Exactly what polarity your device needs and what’s provided by the charger you have in hand can vary. Who do you tell? Somewhere there should be an indicator.

For example, a barrel connector has a connection inside — often just a pin — and a connection outside, typically a ring. One will be the positive connection and the other negative. In the image above the pin in the center is shown as either positive (on the left example) or negative (on the right), with the barrel being the opposite.

You’ll typically find these polarity indications on chargers, and often, but not always, on the device you’re charging. If the latter is the case, you’ll need to find it elsewhere, such as in the product documentation.

This must match your device and the charger you plan to plug into it. No exceptions.

Next up: voltage

Your power supply provides electricity at a certain voltage. Common voltages are 5v, 12v, 24v, and others.

The device you’re connecting to expects a certain voltage.

These voltages should match.

• If the power supply provides a higher voltage than the device expects, it may damage the device.
• If the power supply provides the correct voltage, all is well.
• If the power supply provides a voltage lower than the device expects, it is unlikely to damage the device and also unlikely to work.

We run into problems when we consider how different the voltages can be and still work. For example, if your device expects 12 volts and your power supply/charger provides 12.1 volts, is that a problem? I can only say probably not. It depends on the tolerance and quality of the device in question.

What if the charger provides 13 volts? 18 volts? 24 volts? There’s no way to answer that in general. There are devices that “expect” 12 volts that will tolerate all of those and more, and there are devices that will fail if the voltages are different by those amounts.

In many cases, if the voltage is sufficiently different, then yes, the device could be damaged.

Not as important (for damage): amps or watts

If the voltage is correct, the amperage provided by your power supply or charger is almost guaranteed not to damage your device. (Watts equal volts times amps, so if you have a 65-watt power supply that’s providing 12 volts, it’s capable of providing around 5.4 amps.)

• If the amperage provided by the power supply is lower than the device needs, the device will charge or run slower or not at all. There is a small chance that a poorly designed power supply may overheat.
• If the amperage provided meets the device’s needs, all is well.
• If the amperage rating of the power supply is higher than the device needs, all is well. The device will use only what it needs.

When it comes to damage, amperage ratings are typically the least of your worries.

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