Dirty Caliper Battery Hack

Everyone who has to measure fine things in the workshop knows these calipers sold for a few bucks on e bay or in DIY- malls.

Those calipers are fine, accurate enough for home workshop use and as biggest advance easy to read. (especially if you reach 45 yrs in my case ;)

The big disadvantage is the button cell with 1,5 Volts, who ran empty in a short time. As you know, mostly when the next store who sells button cells, is many kilometers/miles far away.

So i hacked quick and dirty a big power source, an AAA Battery, on the caliper. Now it will last for years with the option, to have a common replacement battery in the house.

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Step 1: Things You Need..

The things you need, should be available in every workshop.

Materials :

The caliper

an AAA Battery (1,5V)

two fine wires, if possible in different colors

Sandpaper , fine above #200

Alternative position:

two neodymium magnets with 10mm diameter, 4 mm holes and 5mm thick.

Tools :

Soldering iron around 25 W and electronics solder

Hot glue gun

wire stripper

Step 2: Fuse It Together..

Remove the isolation from the wires a bit with a wire stripper and solder it gently on the battery clamps of the caliper.

Keep in mind that the middle pole is "-" and the outer is "+" For easy recognizing you can use a red wire for "+"

Sand now the both poles of the battery a bit for better soldering.

Sold the other ends of the wires to the depending poles of the battery. The soldering act on the battery poles must go quick or it will damage the battery.

If you not so familiar in soldering and fear that the battery will explode, after five minutes soldering, you may fix the wires with two neodymium ring-magnets.

Just wrap the stripped ends of the wires through the holes and clip it on the battery's poles.

The main disadvantage of this method is, that the strong magnets will soak every fine metal swarf on it, while you lay the caliper on the workbench. After a few days they will look like hedgehogs or shorten circuit the battery.

If you are mainly wood-crafter, this will be no problem for you ;)

As last step glue the connected battery on the backside of the caliper and enjoy an always usable caliper in your shelf..

Step 3:



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    9 Discussions


    4 years ago on Step 2

    Although you will loose caliper functions with this (I mean, some ways to measure will become impossible), this can be very handy when you need to make the same measurement all day long (in a production line for instance).

    Thanks for the instructable!

    1 reply

    Reply 4 years ago on Step 2

    Yep, you `re right with this! Especially when i measure some piece clutched in the lathes chuck, the piggy packed battery can be a space problem. The main thought was to get a longer battery lifetime. Thanks for the hint anyway :)


    4 years ago on Introduction

    Great suggestion, oddly enough My calipers were acting up, I tested the battery and it was pooped. I had a bunch that I bought from some place like Deals Extreme. I tested seven and came up with one that would work worth a hoot. I'll be remembering this little fix. I figure a Person can sleeve the rig with enough rubber or even electrical tape to keep the metal slivers at bay. ~:- }


    4 years ago

    Neat fix, going to try one using a wood plug to sub for the button cell so can still use a button cell if I want. Will update when I get it done. Just a quick no-tech fix I found to extend the button cell life, I still have the foam cut out case for mine. I cut a space for the battery and store the two separate, I get a couple years out of a cell like this but still worth building an adaptor.


    5 years ago

    Nice improvisation so long you don't need to measure something that requires you to lay the calipers down flat. I cringe at the thought of doing that to mine. However I do recognize that sometimes you need to do something like that when you're resources are limited. I wonder if hearing aids button cell would work. They tend to be economical.


    Reply 5 years ago

    Never thought on another type of battery and didn't know that silver oxide last longer than the shipped. A good idea anyway :-) I ve done this, to quickly have an working caliper with stuff laying around. BTW I had three calipers with empty battery before here.


    Reply 5 years ago on Introduction

    Well, before you hack your other two sets, give them a try. They are very good in low draw and intermittently used test equipment, like a set of calipers, a dmm, or the like. A silver oxide LR44 can last 3-4 times as long as an alkaline LR44 under these conditions.

    They also make a good voltage reference. The put out exactly 1.55V up until they die.