Okay to use replacement laptop charger that is .5v more and .2a less than original?

July 6, 2012 6:14 PM

Ordered a 18.5v ~ 4.9a laptop charger on Amazon, but received a 19v ~ 4.7a charger. Is it okay to use? It seemed to work for the hour that I tested it, but I wasn't sure if I should continue using it.
posted by Bushmiller to computers & internet (4 answers total)

It should be okay although it's possible it will take longer to charge and/or run a little hotter than the original.
posted by tommasz at 6:23 PM on July 6, 2012

Yes, it will be fine.
posted by spiderskull at 6:23 PM on July 6, 2012

I've been running my laptop on recycled power supplies ranging from 14V to 20V, 1A to 4A, and 8 years later, it's fine. Some of those under perform enough that they can't recharge a flat battery AND run the laptop simultaneously, but you're miles from that and pretty much bang on the mark.

Technically, it would have been safer if you got one with slightly lower voltage and higher ampage, rather than the other way around, but those values are so close I wouldn't hesitate to use it. In fact they're so close it might even be within tolerance of the part you ordered. +/- 0.5V is a pretty common allowance at a mere 5V, and at 20V it's a much much smaller variance.
posted by -harlequin- at 6:33 PM on July 6, 2012

It will be fine. Inside the computer you're feeding an array of switching regulators all of which have a very wide tolerance for input voltages; as harlequin notes they are very forgiving of input voltage variations. You wouldn't want to go much more than 150% over rated just in case you're feeding a short-specified electrolytic or tantalum capacitor, but 5% over is well within spec for everything. And your new brick is probably capable of putting out 150% of its rated amperage pretty much forever.
posted by localroger at 5:41 AM on July 7, 2012