Thanks for the recommendation. I use a voltmeter (multimeter), which gives a much rougher estimate than this tester. There are circumstances where a voltage reading may seriously mislead you - but it is still good enough for me and my humble needs.

One weakness of this tester (above link): It can't check AA or AAA lithium primaries... so no good for this specific SPOT modell. (AA/AAA lithium are rated 1.5v, not 3v. BTW, fresh AA/AAA lithium should have a closed circuit voltage of 1.6-1.7 volts).


For me, knowing the capacity with higher precision wouldn't solve the hassle of using primaries on a regular basis. I'd just end up with lots of 50% used batteries sitting on a shelf somewhere. Can't waste a battery that has 50% left, but certainly don't feel like sticking anything but fresh batteries into the unit when heading out for a trip...


As stated several times above: For emergency use - Lithium primaries, no doubt about it! And carry spares!