What's inside a 9V battery? [link]

[JimRayden]

In case there are some who are wondering but hasn't found the time to open one up.

http://www.makezine.com/blog/archive/2007/01/whats_inside_a.html

Cool.

---------
Jimbo

[Seljer]

I've opened up plenty of them, reusing the connectors to make new battery snaps since I always seem to have run out of them

[Mark Hammer]

What's shown at the link is a "good" one.  Crappy 9v batteries are essentially stacked "slugs" rather than individual sealed cells.  Some insights about battery performance can be derived from the picture, though.  The individual cell type, as shown, have spot-welded connections between the cells in series.  While here is not much surface area, the interconnections are low resistance.  Slugs, in contrast, have surface connections between them which are broad but susceptibel to drift towards higher resistances.  Apparently the upshot is that while the sealed cell type are not as capable of delivering tons of instantaneous current (small surface contact between cells), the consistently lower resistance connection between cells allows them to deliver current consistently over a longer lifespan.

[Paul Marossy]

What's shown at the link is a "good" one.  Crappy 9v batteries are essentially stacked "slugs" rather than individual sealed cells.

I remember that's how 9V batteries were made in the 70s. I guess that was before the advent of the alkaline battery? I remember dissecting a recently manufactured alkaline battery to make a battery snap from it, and that's what I was expecting to find inside of it because it said "pile alkaline" on the battery. But, instead, it looked just like in the picture.

Some insights about battery performance can be derived from the picture, though.  The individual cell type, as shown, have spot-welded connections between the cells in series.  While here is not much surface area, the interconnections are low resistance.  Slugs, in contrast, have surface connections between them which are broad but susceptibel to drift towards higher resistances.

Which is how you get that "dying battery sound" in a Fuzz Face. 

Apparently the upshot is that while the sealed cell type are not as capable of delivering tons of instantaneous current (small surface contact between cells), the consistently lower resistance connection between cells allows them to deliver current consistently over a longer lifespan.

Which I guess is why they work well in guitar effects?

[Mark Hammer]

I don't know if its why they work "well", but it probably lies at the heart of things like Eric Johnson saying how he can tell what type of battery is being used.  It also means that electronically simulating "dying batteries" is likely a little more complex than we have made it out to be.  Not impossible to simulate, by any stretch of the imagination, just a little different and perhaps a little more specific (i.e., simulating a dying alkaline is not the same as simulating a dying carbon-zinc or NiMH).

[Paul Marossy]

It also means that electronically simulating "dying batteries" is likely a little more complex than we have made it out to be.  Not impossible to simulate, by any stretch of the imagination, just a little different and perhaps a little more specific (i.e., simulating a dying alkaline is not the same as simulating a dying carbon-zinc or NiMH).

Yeah, I could agree with that. 

[darron]

they are quadruple A's...

here's a little video:

http://www.spikedhumor.com/articles/76000/9_Volt_Battery_Hack.html