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Our laptops allow us to be more mobile than ever before, but still always in search of convenient outlets to charge them. If you are in the middle of charging a laptop and need to move to a different outlet while it is still running, will it damage it? Today’s SuperUser Q&A post has the answer to a curious reader’s question.

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

Photo courtesy of Alan Levine (Flickr).

The Question

SuperUser reader Donna wants to know if it is safe to unplug a laptop while it is running, then plug it back in:

Am I damaging my Hewlett-Packard laptop by leaving it running, unplugging it from an outlet, then walking a few feet to the next outlet and plugging it back in? My brother-in-law says that I am.

Is it safe to unplug a laptop while it is running, then plug it back in?

The Answer

SuperUser contributors Journeyman Geek and Schwern have the answer for us. First up, Journeyman Geek:

No, it should be fine. Laptops are designed to switch between battery and main power.

Stuff to watch out for? Tripping hazards. While barrel connectors are fairly robust, they have been known to fail, especially with a sideways “impact” force. Completely unplugging the power connector would mitigate both this and the risk of tripping. There are special mechanisms for laptop HDDs that park the head in case you drop it.

In essence, anything that can kill a laptop while moving it would kill it anyway. I have had a few desktop divas experience the same failure modes, so it is not especially dangerous to move a laptop.

Followed by the answer from Schwern:

Your brother-in-law has an outdated view of how rechargeable batteries work. Older laptops used NiCd batteries, which were susceptible to the memory effect. Their maximum charge could be reduced if they were repeatedly partially discharged and then charged. There were all sorts of attempts to mitigate this, including waiting until the battery was discharged before charging it again. It is debatable whether the memory effect was real or not.

Modern laptops use lithium-ion batteries, which have no such problem. They also have sophisticated hardware and software to monitor the battery, keeping it in good condition and preventing anything a consumer is likely to do from harming it.


Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.

Akemi Iwaya Akemi Iwaya
Akemi Iwaya has been part of the How-To Geek team since 2009. She has previously written under the pen name "Asian Angel" and was a Lifehacker intern before joining How-To Geek. She has been quoted as an authoritative source by ZDNet Worldwide.
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