I have a moultrie game camera which has a external 12vdc plug to use instead of D batteries. Has anyone tried making their own battery pack? I have some 6v batteries I was thinking of putting in series to get the 12 volts. And then just adding the connector that fits the camera. Has anyone tried anything like this? Anything to look out for? Or can someone point to some instuctions? I don't want to ruin the unit obviously.