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Battery Holder Behavior

  • Thread starter Watson A.Name - Watt Sun
  • Start date
W

Watson A.Name - Watt Sun

Jan 1, 1970
0
I clipped my PS onto the circuit directly and at 1.5V it measured
186 mA, then I clipped the same PS clips onto the contacts of the
single AA cell holder and it measured 169 to 170 mA, but veried a bit
when the clips were moved. The single cell battery holder is a Rat
Smack 270-401A with the full length of the chintzy leads on it. I'm
surprised that there was that much diff due to the leads and contacts.
Must be the very thin wire. When I use them, I usually trim the leads
down to an inch or so, so that should help.

I went by RS and bought a couple more 270-412 battery holders.
They're 3 AAA cells, so I can fit one snugly inside the 'Coffee Mints'
tin, as I posted here a week or so ago. Makes a nice little 3 LED
light. Store didn't have them out on the shelves, so I asked the
salesdroid if they had them in stock, and he punched the number up on
the screen, and they had them in the store. So I waited for what
seemed an eternity as he went back in the stockroom and rooted around
in some boxes and finally found them. I got 3, but he had 7 total on
hand. One of these, 3 AAA cells, a switch, 3 LEDs with a 33 ohm
resistor for each LED, and a box to put 'em in make a great little
couple hour project - you can put one together while you're watching
some dumb TV program. Now if I could only find a cheaper source of
'Coffee Mints' tins..

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###Got a Question about ELECTRONICS? Check HERE First:###
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Don't be ripped off by the big book dealers. Go to the URL
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Just when you thought you had all this figured out, the gov't
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W

Walter Harley

Jan 1, 1970
0
Watson A.Name - Watt Sun said:
I clipped my PS onto the circuit directly and at 1.5V it measured
186 mA, then I clipped the same PS clips onto the contacts of the
single AA cell holder and it measured 169 to 170 mA, but veried a bit
when the clips were moved.

So, a difference of 0.75 ohms, making the unreasonable assumption that your
circuit is linear, which it's not. Unlikely to be that much resistance in
even 26-ga wire, I think. Are these things held together by rivets at some
point?
 
W

Watson A.Name - Watt Sun

Jan 1, 1970
0
So, a difference of 0.75 ohms, making the unreasonable assumption that your
circuit is linear, which it's not. Unlikely to be that much resistance in
even 26-ga wire, I think. Are these things held together by rivets at some
point?

Yeah, I'm thinking that might be the reason, too (OOps, s/b varied).
Probably the reason why it changew with movement. The wire tables say
26 AWG wire is 41 millionms per foot, and each lead it 6", so the
total for both leads is just about 41 mOhms.

The rivets can't be soldered because they fall right thru the plastic
when they get hot. :-( Cheap metal isn't springy enough to make good
contact. I wonder if some of that conductive glue would help some.
Any other ideas or solutions would be welcome. Probably the best way
would be to buy a higher quality, better made battery holder. But
with some of the holders I use, the odd number of cells puts them at a
disadvantage. It's uncommon to find 1-cell or 3-cell holders, let
alone the higher quality.

--
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###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@@
 
W

Watson A.Name - Watt Sun

Jan 1, 1970
0
Watson said:
Yeah, I'm thinking that might be the reason, too (OOps, s/b varied).
Probably the reason why it changew with movement. The wire tables say
26 AWG wire is 41 millionms per foot, and each lead it 6", so the
total for both leads is just about 41 mOhms.

Just for the halibut, I soldered together a bunch of scrap leads left
over from my LED light making. I got 36" length total, most of the
scraps are marked 26 AWG, but there are 7 strands of very fine wire
making up each one. I put 200 mA thru it and the V drop measured 25
mV, which calculated out to about 42 milliohms per foot. So
experimental results again agree with the theoretical values. But it
is really chintzy wire for use in a battery holder. It's not uncommon
for these AA alkalines to be putting out a half amp, such as in a
flashlight.
The rivets can't be soldered because they fall right thru the plastic
when they get hot. :-( Cheap metal isn't springy enough to make good
contact. I wonder if some of that conductive glue would help some.
Any other ideas or solutions would be welcome. Probably the best way
would be to buy a higher quality, better made battery holder. But
with some of the holders I use, the odd number of cells puts them at a
disadvantage. It's uncommon to find 1-cell or 3-cell holders, let
alone the higher quality.


--
@@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@,@@[email protected]@[email protected],@@[email protected]@[email protected]@[email protected]@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@@[email protected]@[email protected]@@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@@
 
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