Posted by Glyn Davies on 24/02/2021 16:52:52:
I set up an experiment some time ago with my Aldi calliper where I powered it from an external 1.5v source so I could measure the current drawn. I forget the value of current (very small) but it was exactly the same whether the display was on or off.
Ages ago I wired my damaged Lidl caliper up to a fixed power supply and experimented. The current drawn is a few micro-amps and the on/off button made no difference to the power draw. In theory a 100mAh button cell should last at least 10 years, and they don't.
My Lidl caliper turned out to be very sensitive to low voltage, I recall it becoming unreliable at about 1.44V, which is only 0.06V below battery full charge. It appears the electronics fail long before the battery is fully flat. At least mine dropped out as soon as the voltage started to dip. It needs new batteries!
A further issue – just a theory – is that batteries flatten in cheap calipers because they aren't sealed. I guess any trace of condensation in the workshop will discharge the battery faster than normal, causing the drop out voltage to be reached sooner than later. Maybe the batteries in better calipers last simply because they are protected against condensation. Might explain why results vary so much : some unlucky souls have constant battery trouble while others with exactly the same model are OK for years. If the caliper is sensitive to moisture, a damp workshop will do it no good at all.
Last problem might be the quality of the battery. Old batteries run out of puff. Dodgy batteries usually contain a smaller mass of chemicals, and the purity of those chemicals is suspect. And long life depends on purity. Silver batteries hold their voltage better than other types so buying LR44 rather than SR44 could be false economy.
I don't have battery problems: if you do, try sealing the caliper in a plastic bag with a desiccant, and keep it in a drawer safe from condensation. Report back next year! Might make all the difference!
Dave
Edited By SillyOldDuffer on 24/02/2021 17:45:53