@astrid AAAA - Also a battery

9V batteries contain 6 AAAA batteries

@kwayk42 that little factoid about 9V batteries (usually) being nothing more than six AAAA batteries in a trench coat will never not be mind blowing to me.

@astrid

@sysop408 @kwayk42

Huh. So 9V batteries are _actually_ batteries!

@mattdm yeah that brings up so many questions. So few things use AAAA batteries that most people don't even know they exist.

On the other hand, 9V batteries aren't at all uncommon yet manufacturers will often make 6 AAAA batteries first and then use those to make a single 9V? Wouldn't it be more efficient to make the 9V directly and make fewer AAAA's?

This has been bugging me ever since I learned this.

@kwayk42

@leeloo ah! OK, now I've got the opposite question. If they're doing it like this because of the chemistry, how do the ones that don't use 6 AAAA batteries do it? Are they just making 6 flat cells packed into a rectangle instead of cylinders?

@mattdm @kwayk42

@sysop408 @mattdm @kwayk42
Interesting question, the people who have taken those apart would know.

I'm pretty sure lead acid car batteries put plastic walls between the cells (that chemistry gives 2 volts, so also needs six cells for the 12 volts).