I am thinking of rigging an external battery pack for my D200. I have the MB-D200, but that weighs 270g without batteries and makes my camera too big. The EH-6 AC charger supplies 13.7V through a proprietary plug. Therefore, I figure an external battery pack using 9 AA lithiums would provide 13.5V, 41 watt-hours, and weigh 130g (excluding the battery holder and wire) or 200g with alkalines. This compares to 11 WH with a single ENEL3e battery, which gives ~300 shots, so the battery pack should give about 1000 shots. I would need to buy an EH-6 adapter, cut the plug off, and hook it up to the battery pack. The external pack would also be useful for cold weather, where the batteries can be kept warm in a coat pocket. This was done for the D1 by Peter Wolf, though using a lead acid battery (http://www.robgalbraith.com/bins/content_page.asp?cid=7-3731-3741). Buying the adapter just for the plug makes it one expensive plug. Is there any way this could mess up my camera (other than by getting the polarity wrong)? Will the camera have trouble if voltage levels drop as the batteries are used up? Anyone try this for the D200?