Used wrong power supply on lappy

So my wife, bless her intentions, plugged in my Sager's power brick into her Toshiba "cause it fits".

So her Toshiba's fine and runs ok but the question remains, what harm can it do plugging in a 20V 6A power supply to a laptop that is used to expecting a 19V 3.2A power supply?

It charged the battery but it was on fire. It was noticeably hotter and I immediately pulled it and shut it down. I'd say it couldn't have been connected for more than 3 hours, tops.

Thoughts? Answers? Ovbious OMG's? was she thinkings?

 

Some motherboards are able to accept different input voltages. For example, mine can accept 18.5V, 19V, or 20V inputs. I don't know what your wife's Toshiba is rated for, but I'm pretty sure it's not rated to combust. The inductors on the board are probably not designed to handle a 20V input, mainly because of the different line impedance.

 

I don't think it is terribly bad. The circuitry on your laptop has some "tolerance". If the original adapter is rated for 19V, it does not mean that it will *always* give 19.0000V. It could be something in between 18V and 20V (+-5% is fine).

For the amp difference, as long as the adapter's amp value is higher than what the laptop is being designed for, it is OK. The amp value on the adapter means that it is capable of providing that much current. If the laptop does not need that much current, the adapter will provide less. It is not something like the adapter is forcing the laptop to use more power...

So everything seems ok to me...


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Like Ramgen said, it should be fine, 5% tolerance would not seem unreasonable. The laptop internal circuits that charge the battery will regulate the current to the required charge current whether it has 19 or 20 volts input. It may of seemed the battery was hotter, but I would bet it was no hotter than if charged by the Toshiba charger.

Soviet, you should know inductors are a current rated device, not voltage

 

I'll double-second ramgen(if that's possible?!). When talking about 19v, 1v either way isn't an unreasonable tolerance(though it'd be about the design specs).

External PSUs are regulated, so it wouldn't be far off the 20v on the label.

The voltage will again be stepped-down and regulated inside the laptop - so the only part of the laptop to "see" the higher input voltage will be its own DC regulators - and these can typically handle quite a wide range of voltage ranges, with the excess dumped as heat.

Is it possible the regulator was dumping a little more heat than usual, but the problem made more noticeable by leaving the laptop on a bed or thick rug whilst charging?

Look up the datasheet for a LM7812 - it's likely not what is used in your laptop, but it's a pretty typical voltage regulator. It'll put out 12v, give or take 0.5v, with any input from 14.5v right up to 30v.

You've likely hurt nothing...

 

There's nothing wrong with it, for overclocking purpose, some people actually buys a higher power adapter purposely.

 

Ok-e-dokie, so it's cool for small amounts of use but long term probably not a good idea since I'm thinking it's heat output was higher due to the higher power input(could be that or maybe cause she puts her lappy on the couch, on top of a blanket-talk about killing a good machine quick!)

Anyways, thanks guys for the input. And rep added to ramgen.