I am using the 12 volt 300 energizer series batteries on my Wildview EZ Cam and also on my Spy Point IRB. The cameras are wired inside to reduce the incoming voltage to 6 volt.
By using the 12 volt external, gives you a larger storage capacity which some cameras require to operate in colder temperatures. My Wild Wiew have worked down to -30 degree Fahrenheit. The Spy Point as claimed by the maunufacturer should go do to +5 degree Fahrenheit. Mine have been shutting down around +15 to +20 degree Fahrenheit. I have had 14 Wild View EZ Cam and 4 Spy Point IRB. In the colder weather the "C" batteries lose voltage. Bring them back in to warm up, they will regain some but not all. Leave a flashlight in a vehicle over night when cold and try it in the morning. The light will be pretty dim. Putting the flash light in a refridgerater (not the freezer part) will also give you an example if you are in a warmer atmosphere.
Setting out a fully charged good quality 12 volt battery, will last several months providing the camera does not have an internal weakness causing a draw down in voltage. I check my batteries a couple times a week when swapping out SD cards. I use a digital meter.
Bushnell 2009, 2010 will accept either 4 AA or 8 AA batteries. If using 4 batteries, they must either all be placed in the top four slots or the lower four slots. The top four are wired in series. The bottom four are wired in series. Now both set of four are then wired in parallal. This is why the total voltage is only six volt not 12 volt. The external port on the Bushnell is only 6 volt. If using the external port, the centre of the barrel plug is positive so this wire must go to the positive post of the battery. Hooking up in reverse will fry a component inside the camera in the external port wiring circuit.