Battery Life In Digital Devices

G'day.

I have a few digital devices (caliper & micrometer) that require a small (typically Energiser A76) battery.

As they are only used about once a week I was disappointed that once inserted into the device, the life expectancy of the batteries is only a few months.

I suspect that small current is being drawn continuously when the devices are OFF to 'remember' the zero data. I suppose one could always remove the batteries between infrequent uses, but that is a pita and I'm always worrying about loosing the tiny screws or stripping the thread in the hole.

Fortunately, I have my trusty old mechanical Moore & Wright, Mitutoyo etc analogue devices for back-up.

Any thoughts on this?

Regards from the land of the kangaroo

Hi Danny,

I use silver oxide batteries (SR44) in my calipers, and they last for over a year. Other types of battery may have a shorter life expectancy.

Regards

Thor

In general I find that life of those small cells can vary quite a lot - one factor is how long they have been laying around in the shop (or your drawer).

I suspect as well that some of the very cheap cells may not have as high capacity as 'known' brands.

It's also worth cleaning the contacts in the device when replacing the cell - a little dirt/grease can have a surprisingly large effect.

Hi Danny ,

I know what you mean !

I have 4 digital calipers and i get varying battery life from a few months to over a year .

As Thor mentioned Silver oxide will last longer but cost a little more and you could probably pick up some on Ebay cheaply - probably out of Hong Kong etc and usually with free shipping .

I have one set of calipers that is over 10 yrs old that tends to chew batteries and it does not have auto power off which is very annoying especially when you open the case to find the damned thing is still on 2 days later !

A recent purchase has a power off feature but when you press the power button it zeros itelf so no memory function - usually not an issue but ....

Now waiting for a new set of Mitutoyo to arrive as all the others are only cheapies but good for general work .
Once they arrive i will have a play and compare the quality , accuracy etc then relegate each one to where i need it most .

I would have thought by now that the manufacturers of these tools would have looked at different options for batteries as i don't think it would be difficult to make them use AAAA or AAA which could be rechergeable or at least a small slide switch to disconnect the battery .

Imagine having the case set up as a charging dock and the tool using a lithium ion battery or similar !

I had a set of Hafco DROs on my X2 mill that used batteries and converted it to run from a powerpack as it chewed batteries like nothing i have ever seen before ! The auto off feature really gave me hell especially the Zaxis unit from measumax - it did not like using anything other than the supplied NiCad on the display which eventually died .

I ended up buying the newer version that comes with a power pack and can run on batteries or the supplied power pack . I found that the display flickered using the power pack so i had a think about it and ended up testing the switchmode power pack with an oscilliscope which showed some noise .
I tried everything to smooth that ripple out and just could not get it right so i tried an old transformer type power supply - Bingo ! the flicker was gone ! My guess is the display has an internal clock or oscillator that is close to or a harmonic of the frequency of the ripple in the switchmode supply and the old transformer type had one at 50HZ so too low to affect anything .

Ian

On most of these devices the only effect of the "power off" button is to turn the display off.

Russell.

I use Energizer 357/303 Silver Oxide in my Mitutoyo caliper.

... Long shelf life, and excellent performance. [*]

Using cheap Alkaline cells in good equipment is a false economy.

MichaelG.

.

[*]

if your instrument drains these quickly, then it's a bad design [or faulty]

Edit: Here is one of many suppliers

Edited By Michael Gilligan on 27/09/2013 09:28:26

.

... which is fine IF you can do it whilst holding only one terminal

... it's rather like working on overhead power lines

But: never underestimate the stupidity of "tradesmen"

MichaelG.

The tweezers have a reason. Insulated obviously better,though not necessary if you hold the cell properly. Don't use bare hands- clean tissue will do.

You really shouldn't be rude about tradesmen unless you know the whole story and they really ARE being stupid.

.

Hence the use of quotation marks around the word

MichaelG.

How about a box for the digital calipers with a solar cell on the lid, and a rechargable battery in the tool.

Ian S C

My experience is certainly that it is unwise to buy cheap cells. Even if you work on the principal that buy cheap and change often saves money in the long run how frustrating is to to find your tool not working when you have no spare battery!

Ian that's an idea but it's a bit of a faff surely ? - and you would need that set up for all your digital measuring stuff.

There is a lot to be said for the old mechanical means of measurement but, of course, the digital display somehow (quite wrongly!) has more authority.

Norman

Edited By NJH on 27/09/2013 12:29:43

These cells seem to be used in so much equipment now, the display on my card reader supplied by the bank became dim when I checked it is fitted with 4x44 type cells, the building society supplied one that has 2x 2032 cells.

When I add this to my digital mike and calipers that is potentially a lot of batteries per year.

This certainly means buying cheap packs works for me, some suppliers have SR44 and 2032 in packs of 5 at under £4.

7Dayshop.com have packs of 5 x SR44 cells for £0.99 delivered & the price drops if you buy multiple packs. I have been using them for a while now & they last much longer than the cheap LR44s I used previously.

Well, it appears that I spoke to soon as I had an email.

**LINK**

It's amazing who monitors these groups!

* Danny M *

I bought a cheap unnamed digital caliper about three years ago, the seller thru' in a spare battery, SR44. Still on the original batt.. Don't use it much, I prefer my old vernier, but must be more than only the display switching off.

.

That looks rather good

... Except that I'm often "working in the dark"

MichaelG.

Try switching it off, moving the slider, and switching it on again. If it still reads correctly then everything but the display has been working. They don't have absolute position sensing, they rely on counting pulses continuously.

Russell.

Good quality SR44 (ie Duracell) can be had cheap as chips on eBay. The biggest killer seems to be very low workshop temps. Avoiding low temperatures, mine typically do a "yearish" , I go through quite a few batteries, but only because I've got quite afew things that use them.

Temperature is all. We could all have longer life calipers if we accept larger cells (Arc do some with lithium 2032s in) or even AAAs.

One alternative is rechargeable button NIMH cells, but of course these self-discharge faster than the silver ones wear out.

Neil