Laptop Charger help - can I use a replacement with higher Volt,Amp,Watt, etc?

[The Stig]

Got someone at work asking me if I can help them with a laptop charger.

Upon inspection, her one is busted (exposed cables and such), and is an Acer laptop.

I know I have an acer laptop at home that isn't used anymore, and offered to check the charger first before we go buy something online.

I know the pin size is the same, but requirements are not.

Her laptop's charger:

Power Provided 65 Watts
Input Voltage 100V - 240V
Output Voltage 19.0V
Output Current 3.42A

My charger I intend to give her

Power Provided 90 Watts
Input Voltage AC100V-240V
Output Voltage DC19V
Output Current 4.74A

Judging by the specs, my charger has a superior Watt and output rating. I was wondering if this was OK to use? I don't want to accidentally set her laptop on fire... or worst

I was reading around and can't find a concrete answer, and was getting progressively paranoid about people saying it'll heat up/explode/kill laptop.

I'm assuming the laptop will only draw as much as it needs, rather than the charger overpumping the laptop and eventually killing it?

[Niya]

The only thing that has to match is the volt value. Ampere (and as a result from that, watt) don't matter as long as they aren't too much below the old value.
So your charger should fit perfectly and might even charge the battery a bit faster than the stock one.

[The Stig]

Nice, this will be great then! She saves money and my charger can be repurposed. Thanks!

[Niya]

There's one more thing you might wanna check, but since both are for Acer laptops it's rather unlikely to not match: plug polarity. Somewhere on the label with the V/A/W values is a little diagram that shows if the inner or outer pin of the plug is positive.
Especially for universal chargers this is really important.

[The Stig]

The diagrams match, yup. Thanks!

Actually she decided against it in the end after I quickly explained the simple figures, and wanted a genuine/official replacement. While strictly that wasn't possible, I did find one on ebay with the letters ACER on it and the seller saying it's genuine. Dubious about it being genuine, but nevermind, but the specs match the old charger.

As this is her primary machine at work I was unwilling to push that she uses mine. She's obviously concerned and I didn't want to be a typical tech person that pushes hard for something. She's comfortable with doing this: http://www.ebay.co.uk/itm/New-Genuin...-/291834881783

Still, I learnt a few things between yesterday and now.