Dave thanks for giving mugatea a full explanation of Ohm's law vs my 'wrongs' but I believe he simply believe he 'knows' better and will ignore it fully, thus the reason I didn't bother going into details...
Until he admits he is wrong and admits he doesn't even have a grasp of even the basics explaining it to him is really fruitless...
Dave explination was good, but I really do know and understand Ohm's Law. Maybe I am not explaining myself well enough.
The bottom line is that you said you can't replace (2) CR2016's with (1) CR2032, because it is 6v not 3v. The answer of 6v is too general, you need more info to come to a conclution. It works and it is not Luck. mathematical reasons why it works.
I could go on and answer all the things you tried to prove me wrong with Example. You said: 4 AAA batteries will have the same brightness as 4 D batteries, it just won'tlast as long.
This can't be true using Ohm's Law or Watt's Law since AAA batteries current capacity is way less than D batteries. Your friends would not want to prove you wrong.
But, I Don't have the time. "Wrong LOL", does not make someone right.
What I did works (replacing the 2 CR2016's with 1 CR2032). I did not intend to discredit you or embarrass you........ You came out swinging.
So if you want to believe everything I am saying is wrong, fine. But what I do know is (replacing the 2 CR2016's with 1 CR2032) Works! We can all learn something.
Again, sorry for embarrassing you.