Digital callipers are so straightforward to use that I guess most of us don't bother to read the instructions, which often call for a 1.55V silver oxide cell to be used - not a 1.5V one. I suspect that the short battery life that many mention is due to using 1.5V alkaline or zinc manganese cells rather than silver oxide. Under 'troubleshooting' the instructions will generally say:
Quote:
8-<
Power Source: One silver oxide 1.55V LR44, capacity 180 mAh. Current <20uA
'Troubleshooting': Digits flash randomly or all five digits flash simultaneously: Battery Voltage below 1.45V.
Unquote.
8-<
Not only do alkaline/zinc chloride cells have a lower voltage of 5V when new, they have a a lower capacity, and quite a different discharge curve. If you look at the attached discharge graph of a 1.5V LR44 zinc manganese cell, you will see that it doesn't take long for the voltage to fall below 1.45V. Conversely if you look at the discharge curve of the SR44 silver oxide cell, you will see that the voltage remains stable at well above 1.5V until it expiries and the voltage falls off a cliff. Hence, it doesn't 'run down' - it dies when its distance has run.
I always use silver oxide, in my callipers and they last at least a year.
It's easy to make a mistake when buying them, even though it does usually state either alkaline 1.5V or Silver Oxide 1.55V on the package.
EG, these are both Energizer brand, both LR44, and both packages look almost identical except for the small print:
1.5V Alkaline:
https://www.amazon.co.uk/Energizer-L...GXNDMMD3ETRRJ1
1.55V Silver Oxide:
https://www.amazon.co.uk/Energizer-S.../dp/B000IX2GXI
People often say 'I can buy a sheet full of LR44 cells from Poundland. Well yes you can, but what you see isn't always what you get.
As to the title of this thread, the terms 'cheap' & 'expensive' are subjective.
To my mind, ÂŁ20 is more than enough to pay - a lot of them are fairly generic, whatever the brand. I think the 100% plastic ones are best avoided - all the rest are stainless steel. I sometimes use mine for measuring fine wire gauges, (0.03mm - 0.1mm) and all three of my callipers measure the same. +/- 1% and 2 decimal places is quite adequate for my needs. I'm an old guy in a garden shed - I'm not putting rockets into space.
Just my thoughts.