Question about using 8.4 v NiMH battery pack

I don't have very much experience working with electronics, so forgive me if I ask an obvious question.

I have this battery, a NiMH 7-Cell 8.4V 5000mAh.

I was wondering if there would be any complications in powering my board with that, through a DC port adapter. From what I've read, the tolerance for the DC port is 7-12 volts, so I don't see why there would be any complications with the 8.4 volts, but my friends disagreed when I suggested using it. Would I need something like a voltage regulator?

Thanks.

Feeding 8.4V into the barrel jack on the Arduino board will be fine.
The onboard 5V regulator will run from that without issue.

Don't listen to those friends. Sometimes the naysaying crowd needs a kick in the pants because they get so complacent being idiotically safe and wrong.

That looks like a great battery for a power hungry Arduino project!

Thanks for the help, I'll buy the adapter tomorrow.