according to this ebay listing
https/www.amazon.com/Dv6-6135dx-Dv6-6167cl-Dv7-6154nr-Dv7-6157cl-Dv7-6165us/dp/B00DBRWSWM the charger that came with it was also 65w. you could probably get away with the one you have handy, or you could get a new one designed for your laptop. using a different one won't necessarily cause any issues if it is the right power output.
check the label of the one you have and compare it to the image in the ad i linked. if the voltage is the same, then you should be good to go using it. don't want to mix voltages. would be like using a 9 volt battery in place of a 12v one. or vice versa. not the power the laptop was designed to use. so verify the voltage is the same before using any adapter. if it is not, then you'll need a new charger