A little necroposting because I promised an update when the time came.
One of the items much discussed was the Apple wireless keyboard. So, back in February, the 17th to be precise, I put two new Duracell Industrial alkaline AAs in my Apple Bluetooth keyboard. After a few weeks of low battery warnings, starting at an indicated 10% according to Apple's drivers, today it got to 4% and I decided it was finally time to change the batteries.
Interestingly, the unloaded voltage of the cells I just took out were 1.16V and 1.17V (10Mohm meter, so a tiny load ~120nA) - suspiciously close to the 1.2V figure Batteroo were always flinging about, perhaps it's where they got that figure from initially.
This is one of the rare occasions where measuring a cell's unloaded voltage is probably justified as that's what the keyboard itself is most likely going to be measuring. That is, the load the keyboard presents is negligible except when it's transmitting, when it is transmitting it pulls a sharp current pulse and then goes back to idling. Obviously it's unlikely that it is going to have the measurement sophistication to measure the battery during a pulse, measurement during idle is much more likely both from an instrumentation point of view and a coding point of view.
Just for completeness I also measured each cell with a 4k load (an educated guess at a mean loading in circuit) in parallel and got the same voltages, with the only difference being instead of a steady reading at the 10 uV level it was slowly drifting down, as you would expect.
Anyway, the Batterizer/Batteroo testing issue is a dead one but I remember promising an update when I needed to change batteries so that was it. It might be a useful data point for someone in the future.
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