Welcome to the Dell Community  @philou 50 

This applies to most if not all laptops.

Look on the bottom of the laptop or under the battery for a label with the "Power Requirements"

19.5V ~ 12.3A 

Volts x Amps = Watts

19.5 x 12.3 = 239.85 "240Watts"

Then look on the AC adapter for the Volts and Amps.

The AC adapter's output Wattage should be equal to or greater than the laptops "Power Requirements"

BUT NEVER SMALLER.

Best regards,

U2

tag

on the battery outpout 19.5V, same as power supply  19.5 V , 3.5 A (model GA240PE1-00)