Raspberry Pi B power supply limit

[foulquesnera]

Hello,
I search for my Bot to offer maximum power ressources to the RaspPi B (with usb-wifi antenna).
I own a old Hand Electric Drill battery delivering 18,5 v.

1) Can I use it, with connection on micro-usb connector ?
2) Or is there an other connection point ?
3) or do I need to regulate this power source ?

Best regards.

[riklaunim]

Raspberry Pi needs a 5V power supply. Only 5V.

[DougieLawson]

If you attach 18V5 to your Raspberry Pi you will have a very dead piece of pi that's headed for the recycling.

You'll need to use a voltage regulator to drop 18V5 to 5V0. Don't use a 7805 it will glow red hot with that sort of voltage, you'll want to use a buck converter. http://en.wikipedia.org/wiki/Buck_converter