Posted by petro1head on 09/12/2021 12:42:09:
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I feel the most important aspect is that when you turn them off they are actually off so not draining the battery.
None of mine have a true ON/OFF switch: they all switch off the display only.
On investigation turns out all my Digital Calipers draw a miniscule amount of power. It's a few micro-amps, not enough to explain why cells go flat in under a year. I don't buy cheap batteries off the internet. I've had old stock nearing it's use by date, and a brand where the cells were about 20% lighter than Duracell – ie fewer chemicals inside!
Why do some calipers flatten batteries more than others, when then all test about the same? Something else is going on. All the calipers are kept together on a shelf in my unheated garage workshop.
I noticed the battery in my most expensive caliper, made by Dasqua, lasts much longer than the same make fitted to my cheapo rough work models. The difference appears to be that the Dasqua has an IP56 rating and its battery lid is fitted with a rubber seal.
My hypothesis is condensation kills the batteries. Damp air gets inside ordinary instruments allowing moisture to connect the positive and negative poles of the cell, which are close together all around the rim. The resulting slow discharge reduces battery life rather than cause an obvious fault.
If I'm right, storing a cheap caliper inside a resealable plastic bag with a silica gel absorber would extend battery life. Or buy a caliper with a high IP rating – I see this Mitutoyo is IP67.
Dave