On Mon, 31 Jan 2011 22:44:35 +0000 (UTC), Meat Plow
wrote:


Wouldn't less current being available at the charger just mean the
laptop takes longer to charge, or not power the laptop and a dock and an
aux battery etc?


I don't know for absolute certainty since I've never pushed the envelope
but an underrated laptop PSU is going to work harder than it is designed
to.

That's the bit I'm unsure on. Ok $100 question could be 'are they
short cct protected? Something that limits it's output to a design
maximum can't theoretically be 'overloaded' can it?

This rationally leads to a premature failure.

Whilst I'm sure you are right in many things I'm not (yet) sure it's
always the case with all these things. ;-)

Consider the analogy of
an underrated PSU in a desktop computer similar.

Other than the load on a desktop PSU is a direct thing whereas the
load on a laptop PSU may depend on what it's doing at the time. ie,
Charging and running, or just running etc. I have noticed that on many
battery powered devices it often says it will take longer to charge
the battery if the device is turned on at the time. Is this down to
the heat of running the device /and/ charging the battery or the fact
the chargers can't generally do both to full power?

As I said, I'm not advocating an underrated PSU for anything, just
that there could be 'nearly enough to do it all and cope ok', 'enough
to do it all' and 'more than enough' (and let's hope there aren't any
shorts on here). ;-)

Cheers, T i m

p.s. Daughters (technically) 'smaller than it could take' PSU only
ever runs warm. The one powering our TV runs much hotter.