[HH] performance and value comparison of AA batteries

[Tom Metro]

A UK contract electronics manufacturer, BitBox, has created a pretty
good comparison chart for dozens of brands of AA batteries:
http://www.batteryshowdown.com/index.html

They compared low discharge (200 mA) and high discharge (1 A) rates, and
charted the comparative value (capacity vs. cost) of the batteries. They
looked at 3 non-rechargeable chemistries: zinc ("heavy duty"), alkaline,
and lithium.

Even though the tests are of batteries available in the UK, there is a
fair bit of overlap with what is available here. The general
observations, which I've seen replicated elsewhere, are that zinc
batteries under perform so badly that even their low price doesn't make
up for it; that there is a wide range of off-brand alkaline batteries
that perform very well and are pretty much as good as the name brand
alkalines, and thus are the best value; that lithiums do perform
substantially better, but their higher cost isn't justified unless you
have a high discharge application or need to use them someplace where it
is hard to get at them to change.

Aside from the top performing Energizer Ultimate lithium cells, many of
the specific brands and models they pointed out in their commentary as
being the best, worse, or good value were brands (or at least models)
not available here.

I was disappointed to see that they tested the Energizer Ultimate
lithium cells, but not the somewhat cheaper Energizer Advanced lithium
cells. The latter are less optimized for high discharge, and are more
for long life in low discharge applications. I like to use them in alarm
sensors, especially where I want them to last a full year and hold up to
below zero temperatures (lithium is superior in the cold; I also use
them in the wireless sensor that goes with my refrigerator/freezer monitor).

Interestingly they built their own microcontroller-based test rig.
Actually 5 of them, so they could run tests in parallel. (From the photo
it appears they used an off-the-shelf single board computer (with an STI
micro; probably an STI eval board) that plugs into their custom
motherboard with the battery holder and testing hardware.) The test
board acts as a programmable constant current sink, and captures a bunch
of metrics that are fed to a laptop.

They invite companies to send them batteries for testing, suggesting
they are looking to make the survey more comprehensive, but
interestingly don't say all that much about the design of their tester,
and haven't open sourced the design. Given it is highly unlikely they
are testing batteries and freely publishing the results as a profit
making venture, making the design fully public would seem to be the
logical thing. Then a US hacker could replicate the results using a
variety of US batteries.

 -Tom