Evening all...
I'm fairly free and easy with laptop power supplies. If the voltage is within ±1V or so, the power available isn't too far wrong (most 120W laptops will work fine for web browsing on a 65W adapter), and the polarity is right, then I'll give it a go. I've never had any problems with Acer, HP, or Dell in doing this. I just use my normal check - "Is it on fire?" - to keep an eye on things.
However, it seems a lot of people don't agree with this and absolutely insist that exactly the right voltage is used. Of course you also get those who insist the "amperage" is the same, mainly due to a lack of understanding. They cite "overcharging batteries" amongst other reasons.
I think that you would have to go a long way out of your way to design a DC-DC converter that couldn't deal with a ±10% input voltage range. I also can't see any way that the battery wouldn't be charged correctly, being behind a converter and then a Li-Ion battery charger.
What are people's experience with this? How far have you pushed the limits when powering a laptop?