Exactly! You got it.
I am sorry, I did not mean to be a sarcastic jerk with that reply; it was a totally valid question. I have been up for well over 24 hours (did not sleep last night) and am going to town on this 36mg ejuice with my new Protege that just arrived today! Between the hangover from last night, the lack of sleep and this High MG ejuice, that has never done much for me in the past, till this new PV, I am a little out of it right now.
Actually, feel free to rip on me you are correct there IS a difference, being which I stated above. One is rechargeable, the other is not. Besides that difference, they are the same battery. Again, be careful as all batteries are not made equal, whether you are talking throwaway or rechargeable. I have seen CR's new that were -.2 through +.4 volts (off of what they should be, which is exactly 3 volts) and an amperage range of 680mAh-1700mAh. In most electronic devices 680mAh is nowhere near enough to be of any use. The voltage difference is less concerning as long as its + and not more than .4 past 3v you should be fine.
Just like most of the time when dealing with electricity, amperage is what you are most concerned about. Take a taser for example. 150k volts they say! Well, there is really nowhere near that amount passing through your body, but still if you look at the amps you will find its next to nothing and for good reason. Amps are what will kill you, not volts.