[SOLVED] Need some help for a DC based application

Hey guys, I have been looking for a cheep way to use my Pentax *ist DL camera and get away from using just 4 Nimh batteries that only last about 2 hours or so.

Yeah I know it's sounds silly but I don't want to spend $125for a battery that will last 6-8 hours when i can make the same thing for $15-30?

All in all here is my question

The port on my camera is a size "M" DC 6.5Volt input, I want to use the RC car style batteries (aka the 12Volt ones) with a quick connect style tips like the RC Car based ones.

I have been looking about and trying to find out if you use a LM317 based Voltage adjuster if that would hold the right current to power it and also not have the resister fry from the 12Volts?

here is one I looked up but I have seen pre-built kits that look great but I'm not sure if I would be able to use it.

(had to use the [dot] tag as this be my first post and them not letting me post links)

www[dot]ladyada.net/library/equipt/diypsupp.html

or the pre-built ones here...

www[dot]allspectrum.com/store/product_info.php?products_id=1602

so I like the pre-built ones but will they get to hot being in a small in-closed plastic box?

Any help on this would be great!
Thanks in Adv,
Sean B.

There's no need to hang a box on the side of your camera. Try a lithium ion rechargeable version of the CR-V3 that will fit in your camera. Many 1400mAH versions are available for ≈$16.00. If you get two batteries and a charger that will work in a car, you should be covered for most situations.
Amazon.com: 2P Battery + Charger for Li-Ion CR-V3 CRV3 RCR-V3 +CAR: Electronics

This one claims 2000mAH capacity.
**broken link removed**

Thx for that I looked into them and most people were saying to just stay way from some versions of the CR-V3s. not really sure why but, I'll look into getting a pair and seeing how long they last on a full charge, Thanks again.