Now the mains adapter for the laptop runs at 19.5 V with an output of 4.74 A. That means it would rate at 92.43 W (W=AV).
The universal car adaptor has different Voltage settings and I have locked mine in at 19V. It is rated for 90W and the guy at the shop says that this is just fine. However when I plugged it in for the first (and only time) yesterday a message came up on the laptop screen saying that the adapter was not delivering enough power.
Shop guy says don't worry about it, it might just take a little longer to charge the battery, but it's no problem and won't hurt the computer. I asked him if he'd put that in writing and he got a little shirty with me, saying if I don't want it I can bring it back.
My question is: Is he right - that 2.43 W won't make a difference? Or is running at a slightly lower voltage and Watt rating risking damaging the laptop?
Thanks in advance for your educated answers