How do you check a battery??

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Stingray

Stingray

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What is the correct way to check a 123?

I have some that I took out of my 6P when they got weak. They got mixed in with some good ones and some half used ones (not by me).

If I check them on a normal digital meter, they all show 2.7 to 2.95 volts or so, whether they are new, half used, or the weak ones.

If I check them on a Micranta (radio shack) battery tester (I assume it puts a load on them), some show good, some show dead, some in between. Even the dead ones per the battery checker still show 2.65 volts on the digital meter.

Often alkaline batteries that show good on the battery tester are weak when put in a light.

So....what's the correct way to check batteries?

How do you guys that are always doing run tests, reviews, and so forth get your battery voltage numbers?

tia
 
What causes this to happen?
I find it that alki cells that
I have had laying around for
many years, they might show
a voltage of about 1.35 volts
but as Stingray says under load
they are dim. I've had NiCads
that seem to charge but only
last minutes under load.

-Rebus
 
Here's my 2cents-worth. I could full of it, in which case you'll find out quickly anyway via other members chiming in.

Let's start with one thing, and that is that when you take a voltage with a voltmeter only you ARE applying a load, but it's a theoretically infinite load. When you do what we all are calling "applying a load" you're actually lessening the load and lowering the potential between the electrodes. But that's not what's really causing the voltage drop we're trying to discover with the batteries. The reason you want to test a battery under a less-than-infinite load is the following:

The batteries work on a chemical reaction. If you just want to know why you need to load the battery to test it you can ignore the details of that reaction and imagine the reactants in a goo at both the anode and cathode ends. For a fresh battery there's relatively lots of stuff to react and thus little transport problem for it to react at either the anode or cathode. Electron exchange takes place relatively easily. As the battery runs low though, the reaction becomes all about transport -- getting to the anode or cathode in order to react.

With the battery under no load at all for even a worn out battery the voltage can still be dominated by the potential between the original reactants (voltage difference between the reactants doesn't depend on how much mass there is, it's a function of where these chemical elements sit on the periodic table in comparison with each other). Apply a load and you see right away that there's just zilch for power delivery as all the battery is doing is mostly kinetics, and heat production driving the reactants to the anode/cathode rather than electron exchange. (BTW, this energy loss of the battery is called its "internal resistance", and its value usually reported is for a fresh battery.) And eventually there'll just be nothing left to react either. Simultaneously, under load there's less of each chemical at the anode/cathode sites to provide an energy difference, which is the same thing as what you'll see on the voltmeter that the voltage takes a quick dive down.

Let me bust out with an analogy to express the voltage/power thing. Imagine you're standing at Niagara falls. All that water is rushing down a certain height. That's powerful, right? And it's falling from that certain height whether the dam is up and there's just a trickle or the dam is down and the thing is raging. The voltage is like how far the water falls in height. The power is like how much water goes from top to bottom in a given amount of time. With a battery, you can get a lot of power from a fresh one (lots of electrons flowing across) and with a dead one you have just a trickle of power. Regardless of how much reactant there is, the voltage is the same between them. Let some electrons flow by "applying a load" and the result because of the chemical factors is a bit like lowering the height of the fall. It's not that way with a theoretically infinite power supply, but it is that way with a battery since it has limited power delivery.

With fresh batteries the same transport problem occurs but is only noticeable at a higher load. Internal resistance will just have a battery giving off so much heat at high load that it effectively loses all its energy that way. You can plot a graph of energy-vs-power for a given mass of battery and you'll see that as the power demand increases there's an exponential drop in available electrical energy from the battery. For example, this is what electric car sellers don't want you to know about their cars -- drive at 15mph and you might be able to go 60 miles, but drive at 60mph and you might cut your range down to 10 miles just because of the energy loss in the batteries, even ignoring aerodynamic drag.
(I'm sure an EV nut will chime in on this one.)

Rebus -- The NiCd problem you're describing could be "memory effect". If you regularly charge that type of cell up after only discharging it a bit, then it tends to have minimal power after reaching that point where you usually charge it. In a sense, dying at that same point is its memory. Why this happens isn't well understood.
 
a rather high tech way to check batts is with an esr tester.the best is from **** smith.
http://www.anatekcorp.com/testequipment/esr.htm

Used in the normal way, a cell's 'effective series resistance' shows on the meter's display, indicating its ability to deliver current and voltage regulation. All cells have an ESR characteristic of cell type, size and state of charge. For cells of the same size, NiCads have the lowest ESR, followed by alkaline, Ni-MH, carbon-zinc and others.
Flat and faulty cells will have high ESRs. A dry cell's ESR increases as it is used, going high when flat. A rechargeable cell or pack can be measured while on charge or load, provided the current is steady. Even the tiniest button cells may be checked, as there is no load current.
A high ESR reading may reveal damaged cells or a bad internal connection. All tests are instant and require no other equipment. Checking and matching new cells is another application; the table of typical readings for good cells will help get you started, until you create your own database." Lead-Acid batteries should also be able to be tested...
Internal resistance of batteries Type AA AAA 9V 12V 7.2 (mobile) Package
Ni-Cad 0.03 - - 0.5 0.11 welded
Alkaline 0.12 - 0.8 1.5 spring
Ni-MH 0.35 - - 4.0 welded
Carbon-Zinc 0.45 - 10 5.1 spring
Rechargeable Alkaline - 0.2 - - - single cell
Lead-Acid - - - - - -
Submitted by: Phil Allison, Sydney, edited August 19, JR...
 
Well, I read my post above and someday I'll learn not to post so late at night. Infinite load and infinite resistance are opposites, so ignore my gripe about load/no load terminology. An infinite load would be, say, a short circuit. Oh well, I could post, repost, edit, whatever. I'll leave it at that.
smile.gif
 
Ni-Cad 0.03 - - 0.5 0.11 welded
Alkaline 0.12 - 0.8 1.5 spring
Ni-MH 0.35 - - 4.0 welded
Carbon-Zinc 0.45 - 10 5.1 spring
Rechargeable Alkaline - 0.2 - - - single cell
Lead-Acid - - - - - -
Click to expand...
<font size="2" face="Verdana, Arial">Something's not right here - NiMH cells have 3x the internal resistance of alkalines??? I hardly think so.
 
Thanks for all the info...I appreciate it.

So....given that I have a digital meter and a Micranta battery tester, what's the best way to determine a batteries remaining power. When you guys measure voltages and report it to the group, how are you measuring? With a voltmeter? Using a resistor?
 
spring battery holders introduce resistance.
and early nimh cells sucked for high load apps.
the first ones i got were 1000 mah and internal resistance was so high that a minim@g was dim.
nimh has come a long way.

Originally posted by evan9162:
</font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Ni-Cad 0.03 - - 0.5 0.11 welded
Alkaline 0.12 - 0.8 1.5 spring
Ni-MH 0.35 - - 4.0 welded
Carbon-Zinc 0.45 - 10 5.1 spring
Rechargeable Alkaline - 0.2 - - - single cell
Lead-Acid - - - - - -
Click to expand...
<font size="2" face="Verdana, Arial">Something's not right here - NiMH cells have 3x the internal resistance of alkalines??? I hardly think so.</font><hr /></blockquote><font size="2" face="Verdana, Arial">
 
This looks like it would test any batteries, though $70 is a bit expensive. This store has the BEST battery holders I've seen. I love the wood blocks and the nylon "wallets". The 4AA one also fits 3AA and 2 AAA if you put the AAAs on the sides.

http://www.greenbatteries.com

http://store.yahoo.com/greenbatteries-store/ztsmultes.html
---
This is truly an amazing battery tester. This is the only tester we have ever seen that can quickly indicate the charge level on almost any battery. Inexpensive battery checkers can give a good indication of the charge level of alkaline batteries, but the ZTS Multi-Battery Tester can quickly show the charge level of rechargeable NiMh and NiCd batteries as well.
The ZTS Multi-Battery Tester (MBT) can check more than 25 battery types, including the popular NiMH and NiCd rechargeable batteries. Its microprocessor-controlled pulse load test is the most advanced and accurate available. The MBT computes the battery's remaining power capacity (between 10-100%) during each test. It is easy to use - no switches or settings.
Microprocessor controlled pulse load placed on the battery at the time of testing gives a clear reading of the battery charge level. The ZTS-Multi-Battery tester doesn't have the ability to measure battery capacity (ie it won't be able to check if a battery is 1500 mAh or 2000 mAh) since that requires a tester which completely drains the battery over several hours.
Fully self contained, requires 4 AA batteries which we include.

Testing Capability:

9V alkaline, carbon zinc
6V photo lithium [2CR5,CR223,CR-P2]

3V photo lithium [CR123,CR2]

1.5V alkaline [AAA,AA,C,D,N]

3V lithium coin [CR2016,CR2025,CR2032,58L,1/3N]

1.5V "76" series button [S76,A76,A625,A640]

6V "28" series [28A,S28,28L]

1.2V NiMH, NiCd rechargeable [AAA,AA,C,D]
 
ZTS is the way to go to check 123 lithiums - problem is the ZTS shows "dead" - no lights, when there is enough power in a 123 to light an Arc LS. and run other lower drain equipment..so what do you do? When you get a 'dead' indication on the ZTS for a 123 you can test it on the 3v Li CR battery 'coin cell' test nipple. Then you'll get about an 80% reading on a formerly freshly kilt 'dead' 123... With a little experience you can then extrapolate how much juice is left to run certain pieces of equipment.
The manufacture has stated that doingthis does not harm the ZTS tester.
Lots of info on this if you do a search...
 
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