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The life of a battery can be increased by using the right power supply, but with a proper match, they can be interchanged.

If you have two laptops from the same manufacturer, can you interchange their power sources? One of my laptops has a lighted AC adapter tip and one doesn't. Can I use the lighted adapter on the non-lighted?

In this excerpt from Answercast #26, I look at various power supplies that can safely be interchanged.

Interchanging power supplies

My belief is yes.

Now, I have to throw out the usual caveat that you should double check the outputs of the power supplies that you're talking about and make sure that they are the same voltage.

What you've described is, in fact, exactly what happens here. Over the years, I've had several Dell laptops (and one of the reasons that I like the Dell laptops is that they all happen to use the same power supply plug). After the laptops have gone on to a higher plane, the power supplies remain behind.

So, I have this nice collection of power supplies:

  • They all have the same tip;

  • They all put out the same voltage;

  • And I use them interchangeably.

In fact, some have lighted tips: the newer ones do and the older ones do not.

So, with a certain amount of caution, I'm going to say that sure, it should be fine to do exactly what you're doing: as long as the power supplies are indeed the right voltage, all the same voltage, and all from the same manufacturer.

Article C5466 - June 14, 2012 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

June 15, 2012 9:25 AM

One problem I ran into with Dell power supplies is the power supply not being recognized by the computer if it is not the original PS. I purchased an extra one off eBay to leave at the office, and although it was the same voltage and style, it had a different revision number on the brick. The laptop would always come up with a message that it was an unrecognized power supply and would power the laptop, but not charge the battery and would require me to acknowledge the message before proceeding.

Ken B
June 15, 2012 11:17 AM

Another thing to look at is the polarity. (Which of the two connectors is positive and which is negative.) Along with the voltage, wattage, and other info on the power supply will be a small symbol consisting of three circles (the center one being "broken" and having a dot in the middle), with a "+" in one outer circle and a "-" in the other. One of these outer circles will be connected to the center one, and the other will be connected to a dot in the middle of the center circle.

While I'd be surprised if a laptop manufacturer would use power supplies of the same voltage/wattage/etc, but different polarities, this is definitely a "better safe than sorry" issue.

Ken B
June 15, 2012 11:28 AM

Oh, and Paul brings up another "interesting" issue. Some laptop manufacturers (Dell may be one of them) use "smart" power supplies. In addition to the two power connectors, there is a third connector, which somehow communicates to the laptop information as to what power supply it is. If this connector is missing or broken, or the power supply reports the "wrong" information, the system may not properly use it. (The case where I ran into this allowed the system to run, but it refused to charge the battery, claiming it was "unknown", even though it was the one that came with the system, because the extra pin was damaged.) I'm not sure there's any way to know for sure, unless you know exactly what to look for. But, when buying a replacement from a third party, make sure that the seller says it works with your specific model.

Here's a closeup of a Dell power supply, including the plug. Note pin in the center, which is not there in "regular" connectors.

August 14, 2012 7:16 PM

My daughter's Dell laptop sometimes gives that message (since new), yet it still charges fine.

Oh, and Thanks for "extra tip" tip.

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