Battery consumption in stompboxes.

[Burstbucker]

I was wondering how long a fresh 9volt battery would last in an effect that draws 7 or 8 mAmps.

[Hal]

most 9v's are around 120 mah, alkaline's slightly greater than this, IIRC.  I could be a bit off.

120mah/8ma = 15 hours.

[Burstbucker]

I would have thought that I could have gotten more than 15 hours out of a fresh battery but I guess not.

Thanks for that info!

[onboard]

Hang on - an alkaline 9V should be 565mAh, give or take.

So a 7 to 8 mA draw should get you around 75 hours continuous operation.

I don't know if that takes into account that things start flattening out once the battery gets below 7.5V...

Check out this link for some good reading.

[Jason Stout]

Here's a datasheet for an alkaline 9V from Duracell.

http://duracell.com/oem/Pdf/new/1604_US_CT.pdf

[onboard]

Huh, no straight-up mAh rating. The discharge graph on page two is showing 50+ service hours at a 10mA draw. "Service hours" referring to "usuable" battery strength, compared to full to flat?

After scanning the net, I'm seeing anywhere from 500mAh to an Energizer rated for 625mAh :shock:

Their Eveready  is the middle of the road 565mAh...