Alternative Battery LR44

I'm no battery expert, but for snots & giggles went to Radio Shack's web site and put LR44 in the search box... it returned this:

Good luck!

Erik

Your choice -- SR44 or SR357 -- both are silver oxide, and interchangeable. And -- for ease of remembering, both are revolver magnum calibers. They cost more than the LR versions, but the nuisance value of the batteries dying frequently makes up for a lot.

I've got a metric Starrett which I bought *new* back in the

1970s or so. (No, it is not for sale. :-)

One of the reasons for digital calipers.

I've not had one of those. Is that the one with the larger digits, too?

You let them play with the old cells, or the blister packs which they came in? it Could be bad news if they swallowed the cells.

Enjoy, DoN.

I can't comment on longer life, but I think AG-13 is the same. Any case, try Ebay, or Froogle. They can't be that gosh awful expensive. Maybe HF has them?

I got a cat laser that runs on two AAA cells, from Ebay. I have a lot of fun with it. I claim to use it for pointing at work, but it's really a cat laser.

SR44

If cheap is your only requirement:

Quality may not be the best, though.

You can get those the same place:

Take the battery out of the caliper when you aren't using it and they will last a decent amount of time.

The problem with that one is it's 2mm per revolution. The bar is marked in cm with 4 ticks between each. So to get the mm you have to count ticks, multiply by 2 & add the dial reading. High resolution, but a nuisance. I'd rather rather have one with 1 cm per revolution.

Bob

I believe it's been mentioned that the LR types are alkaline.. and IME, the cheap ones often go bad just sitting in a drawer, but many have a short shelf life (unlike better quality AAA to D alkaline cells). I've bought the very cheap bulk, no-name, flea market LR44 10 or 20 packs from various sources in the past, and they were the worst.

A couple of years ago the Big Lots stores started stocking a better variety of small cells, and I found the silver oxide SR44 cells in a blister pack of

5 for under $2.. but I think the cost was a little higher the last time I got a few packs. But the SRs are branded (not Ever/Dura) and have dates on the packaging, so it's fairly easy to see that they aren't just salvaged freight which may have been sitting around for a couple of years.

These SRs far outlast even a brand-name LR cell. I put them in anything that uses 44/13 size cells. I take the digital caliper batteries out when I put it back in the case.. there are round cut-out holes in the foam to store them, or some cut-outs can be cut to hold 1-2 extra cells. Marking the battery cover with a bright paint pen helps to prevent it from getting misplaced.

I keep intending to install a tiny switch (from a small LED light or other little gizmo) to be able to shut the power off when not using the calipers, but removing the batteries isn't so inconvenient.. losing the battery cover would be.

(...)

Little switches tend to die early. Ask Palm about that. :)

I like an elastomer carbon button driven by a threaded knob that makes contact between the '+' side of the button cell and the caliper cell contact instead:

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Very good idea, Winston.. it hadn't occurred to me to integrate something into the battery cover, and your solution is ingenious in terms of simplifying the modification.

I guess that's why I hadn't added a switch to the cable plug cover (on the top side), which would require removing material from the cover, opening the display housing and various other steps.. the big one being that the calipers still work reliably after being reassembled.

Thanks, Bill.

If you captured the battery cover to your CAD program, you could create a version of it that included a brass insert for a 3 mm screw. Scrap a keyboard for the carbon button and you are almost done:

Keep us posted, please.

--Winston

Heheh.. you funny, man. My CAD consists of a mechanical pencil and printer paper. Software and I are mostly incompatible.

A threaded shoulder on top of the cover wouldn't be too difficult with a salvaged brass insert from an old plastic-encased product, and maybe a little epoxy.

In lookin over the sichyation, it looks as though the + battery terminal could maybe be trimmed and used like a switch contact with a little lever utilized to move a tab, to either (a) act as an insulator in the off position, lifts in the on position (b) move the contact away from the battery in the off position, move the contact to the battery in the on position.

Your threaded solution wouldn't rely on the durability of the Chinese soldering, which is always suspect.

One drawback I see to removing the battery between uses, is that the cavities can get dust/debris in there when the cover remains off. I can see this in the small caliper I keep stored next to my desk, which is a fairly clean area.

Will do.

I was too, until I tried Rhino3D. Just another happy customer!

Good Hack! If the knob were hollow on the back side, you could place the threaded area so that the knob almost completely encloses it. Clean.

Yup. I was considering using the flexibility of the PCB as a spring, with a double sided board in the area of the cell's + surface. Clockwise=on.

Yup.

Which is not nearly as aggravating as losing the cover. :)

This will be cool!

--Winston

Off topic, but what's the paint called that you use to repair the carbon buttons when they fail, and where can you find it?

RWL

Like this?

I don't have any experience with it but the Large Print looks good. :)

--Winston

Not all of us have ten Benjies to throw at a pencil problem.

Anyone use BobCAD? One of the CNC kits of stepper motors + a Gecko G540 I'm eyeing on eBay has Mach3 and BobCAD v21 bundled with it.

-- Do not let your fire go out, spark by irreplacable spark.

In the hopeless swamps of the not quite, the not yet, and the not at all, do not let the hero in your soul perish and leave only frustration for the life you deserved, but never have been able to reach.

The world you desire can be won, it exists, it is real, it is possible, it is yours. -- Ayn Rand

The last place I saw it advertised was from a remote control monger.

$30-35 + s/h nowadays. Crikey!

"keypad repair kit" was the key phrase search.

-- Do not let your fire go out, spark by irreplacable spark.

In the hopeless swamps of the not quite, the not yet, and the not at all, do not let the hero in your soul perish and leave only frustration for the life you deserved, but never have been able to reach.

The world you desire can be won, it exists, it is real, it is possible, it is yours. -- Ayn Rand

I found some more:

Amazon $12.95 eBay $5, and probably worth only that.

-- Do not let your fire go out, spark by irreplacable spark.

In the hopeless swamps of the not quite, the not yet, and the not at all, do not let the hero in your soul perish and leave only frustration for the life you deserved, but never have been able to reach.

The world you desire can be won, it exists, it is real, it is possible, it is yours. -- Ayn Rand

I'm interested in your opinion of it:

--Winston