How fussy are laptop chargers?

swee'pea99

Legendary Member
The real thing is:

1628422862237.png


The old one I have hanging around is:

1628422980165.png


Is that close enough, or will I fry my laptop?

More generally, do they have to be exactly the right spec, or can you be a bit give-or-take?
 

Andy_R

Hard of hearing..I said Herd of Herring..oh FFS..
Location
County Durham
I wouldn't - the output current is over 50% higher than the original
 
The real thing is:

View attachment 603204

The old one I have hanging around is:

View attachment 603205

Is that close enough, or will I fry my laptop?

More generally, do they have to be exactly the right spec, or can you be a bit give-or-take?
The undervoltage won't damage your laptop but on a normal non-laptop PC would cause instability.

As for the large increase in current output, the laptop in theory won't draw more than it needs from the charger.

Whether or not the laptop accepts any charge from the supply at all is a different matter entirely - some laptop manufacturers have an in-built mechanism to prevent you from using an off-brand charger.
 

ianbarton

Über Member
Make sure that the polarity on the bit that plugs into the computer is the same on both power supplies. There is a small diagram somewhere on the charger that looks like a cup and shows you if the central pin is +ve or -ve. Output amps are the maximum it can deliver. It will only deliver whatever your computer needs.
 
Make sure that the polarity on the bit that plugs into the computer is the same on both power supplies. There is a small diagram somewhere on the charger that looks like a cup and shows you if the central pin is +ve or -ve. Output amps are the maximum it can deliver. It will only deliver whatever your computer needs.
Yes, this is an extremely good point.
 
OP
swee'pea99

swee'pea99

Legendary Member
Make sure that the polarity on the bit that plugs into the computer is the same on both power supplies. There is a small diagram somewhere on the charger that looks like a cup and shows you if the central pin is +ve or -ve. Output amps are the maximum it can deliver. It will only deliver whatever your computer needs.
Thanks - excellent tip!

Need I worry about the bold bit? "the laptop in theory won't draw more than it needs" In other words, could the excess amps actually cause damage? (The beastie is an Acer Chromebook 14 CB3-431, in case it makes a difference.)
 

keithmac

Veteran
You don't "pump" current into a battery, the battery (via the Battery Management System) draws what it requires.

If the charger had a lower current capacity it wouldn't be able to maintain the correct voltage.

As said above as long as the polarity on the connector is the same it will be fine (normally the centre is +ve).
 
Need I worry about the bold bit? "the laptop in theory won't draw more than it needs" In other words, could the excess amps actually cause damage? (The beastie is an Acer Chromebook 14 CB3-431, in case it makes a difference.)
The thing I put in bold is almost certainly a non-issue, I just put it there to cover my own ass.
If the device is working normally then it's absolutely not a problem. As @keithmac said, it will only draw what is required.

(Under some circumstances a faulty device can draw more current than normal, but this is vanishingly rare and is usually because something has shorted and the device is goosed anyway.)
 
OP
swee'pea99

swee'pea99

Legendary Member
Thanks all! CC comes up trumps yet again!
 
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