AA-sized conductor (fake battery) wanted

Eldor Inscribed thus:

Whats wrong with a piece of rolled up cardboard ?

--
Best Regards:
                Baron.

Many handheld radios are equipped with exactly this sort of thing (i.e., I have a couple of such radios, each with a pair of die-cast "fake batteries" -- nothing more than 0 ohm spacers). This allows different battery technologies to be used in the radio.

You could fabricate one using a length of copper pipe with suitable "end caps" soldered on.

Cardboard isn't a very good conductor at low voltages :>

How about this:

These would obviously do what the OP wanted -- though the price is not right. One might solder lengths of copper tubing (which you can get at hobby stores) to metal disks -- but I don't know how sturdy they'd be.

WARNING! The following is off-topic -- but worth thinking about.

These dummy cells are supposed to be energy savers, because they let you use only three AA alkaline cells in a four-cell flash. This works, because most flashes operate correctly with nicad or NiMH cells, which are nominally

1.25V (rather than the 1.5V of alkalines).

However, this is a great way to waste money -- and not just the cost of the dummy cell. With only three cells in the flash, you won't be able to discharge them to as low a voltage as you would with four. That means you'll have to discard them sooner, and you'll get less total energy out of them.

It is if you start with a piece of 18 AWG wire in the center!

I was going to suggest searching for Dummy AA Battery, but then another reply already has. That Shack store used to supply those with some of their products.. you might see if they can get them for you.

D Yuniskis' comment refers to a fairly common usage, the dummy cells first became popular when AA nicads batteries became commonly available.

Many portable devices were capable of being powered by AA cells, and since nicad cells were only 1.2V, it required 10 of 'em to operate a device where

8 non-rechargeable cells of 1.5V would be adequate.

So, the equipment manufacturers made the dummy AA "fillers" available to give the user the option of using nicads or conventional cells.

I believe all of the dummies that I've seen have been simple single-piece zinc/aluminum alloy diecast items, with round ends and a flat bar center section to make them more lightweight and cheaper to produce (using less metal).

In recent years, when I've needed such fillers, I've formed them out of heavy gage solid copper wire. I'll start with a close spiral forming a flat disc shape, then move away from it and form another one (with a center pip) at the other end. A straight section in the center, separating two round flat discs the same length as a AA cell.

Any metal washers or discs of the correct diameter with a rigid center separator could be soldered together faster than forming one from solid 12 ga wire. Brass, copper or plated steel parts would be adequate, and the center doesn't need to be cylindrical.

When I was making an external power adapter for a camera, 4 AA cells were arranged in 2 lengthwise pairs (4 cells, 2x2), so I used some nylon rod the same diameter as the cells. I used a plated brass disk for the (-) terminal, and an end cap from a glass fuse for the (+) top terminal.

-- Cheers, WB .............

of

I just called Quantum, and found out that these actually aren't "energy savers" at all. In fact, there might be circuitry in them (which is why there are two models).

If you own a Canon flash (I assume Nikons are the same) and have read the wretched manual, you know that, when using an external power pack, you must leave the AA cells in the flash, because they continue to power the control circuitry. It appears that going from 4 cells to 3 reduces the drain on the cells, and presumably extends their life.

Eldor wrote in news:4d2edb51$0$77558$ snipped-for-privacy@auth.newsreader.octanews.com:

get a dowel of the same diameter as your batteries,cut to length of each cell,cut a groove down the side,and put a copper wire in it,folded over and curled around at the ends. if you wish,you can get fancy and epoxy the wire down.

--
Jim Yanik
jyanik
at
localnet
dot com

Find a dead AA battery. Make sure it's totally discharged. Wrap with aluminum foil. Instant shorted battery.

If you want elegance, take a brass or aluminum shaft that's the same diameter as the AA positive tip. Build up the diameter until it's the same size as the AA outer diameter with cardboard, Duct Tape, or some combination thereof. Maybe a wooden dowel center drilled for the metal rod. Hide everything under some nice looking shrink tube. You may need a wider negative contact area depending on the holder, so adding a brass washer at the base might be useful.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

sreader.octanews.com:

s e

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Or drill a hole up the centre and put a nail through it cut accurately to length.

Neil S.

D Yuniskis Inscribed thus:

Sorry ! My brain fart :-( I meant to write "Whats wrong with a piece of alloy foil wrapped over rolled up cardboard ?"

--
Best Regards:
                     Baron.

Radio Shack used to sell them.

--
Live Fast, Die Young and Leave a Pretty Corpse

Wrapping the foil might be tricky -- especially if it

*is* "foil" -- since you want a durable and reliable contact surface yet can't really tolerate lumps, bumps, etc. "Shrink-wrap-aluminum"! Now *that* would be an idea! :> (not "shrink-WRAPPED-aluminum")

The ideal would be to turn a length of copper dowel to the correct profile and then encase in shrink wrap. But, I suspect the OP doesn't have access to a lathe (though many people *have* lathes so "asking around" could be an option -- note that the profile is probably published as a standard someplace so it's just a matter of getting someone to give you 3 minutes of time on a lathe).

My "dummy cells" look like "I" beams in cross section. I.e., imagine the top and bottom 1/10th of an inch of a cell joined by a thick *sheet* of metal. Very obviously castings and saved on material by not making them solid cylinders.

You could probably adapt a AAA->AA adapter pretty easily. Cost < $1 each from China a couple at a time.

Best regards, Spehro Pefhany

--
"it's the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Check at Home Depot for aluminum rod.

Larry

Thank you, thank you everybody, it's enough :-))) Now I have a few things to try!! :-D

D Yuniskis Inscribed thus:

I've actually used rolled up cardboard and wrapped aluminium cooking foil round it, folding the ends over to make contact surfaces. It works quite well. I imagine that its current carrying capacity would be quite low.

Actually a hacksaw and a short length of 0.5" or 13.0mm bar/rod cut to

2" or 51mm long would do !

I've seen something similar made from mazak alloy.

--
Best Regards:
                Baron.

Why do you need a lathe? Just use a piece of drill rod the right length, and insulate it if there is any chance of a short in the holder.

It isn't expensive and comes in a lot of sizes:

You could get some scrap 6 AWG solid copper wire and wrap it with paper to make it the right size, if you don't want to use steel.

A piece of wood dowel, two brass screws and a piece of wire run from end to end is the traditional method.

--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.