On Wed, 17 Sep 2008 13:36:01 -0700 (PDT), ransley wrote:
> I just tested a few new-old Duracell Alkaline, in the original packs.
> 1.5v aa -aaa and came up with 1.6v new. Is this in spec? or do I have
> 2 meters that are innacurate. My experiance is all cells v. and Lead
> Acid car batteries are more than nominal ratings. Check your car, It
> wont start in winter with 12v. 13.3 is a peak saturated voltage, 12.8
> a mean 100% charge. A 12 v system is in fact optimal at 13v.. A 12v
> car battery is 75% dead at 12v.
That's about right. I seem to recall getting open circuit
voltages with fresh alkalines ranging from about 1.56 to 1.6 volts.
If I recall correctly, lead acid cells have a 2.2v nominal voltage,
not 2v, so a 6 cell battery should provide 13.2 volts, or slightly
more while being charged. From Energizer's App. Manual :
> Battery Testing
> Measuring the open circuit voltage (OCV) of a battery to determine
> the amount of service life will yield a rough estimate. A more accurate
> method is to measure the closed circuit voltage (CCV) of the battery.
> This is accomplished by putting the battery under load for one to two
> seconds and measuring the CCV. If the battery voltage is greater than
> or equal to 1.1 volts, the battery has approximately 20% service left.
> The load is determined by the size and type of battery. In the case of a
> single cylindrical 1.5 volt Alkaline or Carbon Zinc battery, the load
> would be approximately 8 ohms. Otherwise, an OCV reading of 1.5
> volts or greater for a single cylindrical 1.5 volt Alkaline or Carbon Zinc
> battery indicates essentially an undischarged battery or one that has
> been discharged less than 10%.
Don't believe the "greater than or equal to 1.1 volts" though.
That implies that a reading of 1.4 volts would also indicate 20%
service left. Also, the amount of life remaining depends on the
current draw as well as the device's minimum operating voltage since
the batteries have their own internal resistance. Some of my analog
radios operate (at moderately low volume) with cell voltages below
0.4 volts. They draw only about 10-15ma, vs. the 100ma, 250ma,
500ma and greater currents that Energizer normally uses in its
battery life charts, so at 1.1volts, those alkalines have much more
than 20% service life remaining.
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