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Physics of electricity question

eddie1261

eddie1261

Solar Enthusiast
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Sep 20, 2019
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Location
Northeast Ohio
Somebody here will know this, because it is intriguing to me. I have 4 AA batteries on my desk. Full power, of course, is 1.5v. Each of these batteries right now sits at 1.2v when I check them with my meter. When I look at any 2 of them as a pair, I would expect them to be 2.4, since 1.2 + 1.2 = 2.4. However, any pair of those 1.2v batteries reads to be 2.5v. Any combination of 3 of them reads at 3.8v when I expect 3.6. And all 4 reads at 5.2, when I expect 4.8. So apparently there is something synergistic in the mix here that in series the voltage is higher than the total of the individual parts. Is the answer as simple as "because it does" or is there some answer that includes physics and/or chemistry that I never learned about?
 
Hi eddie1261,
How about this 1.25 + 1.25 = 2.5, and so on, what I think is missing is the 100th of a millivolt?! 0.5 millivolt, 0.05 100th millivolt, 0.005 10th millivolt, 0.0005 ?microvolt? I think microvolt.. added together to get!
Am I right with the units? It's been a while...
Temperature of the cell (Physical), chemistry and age although (if) new... Play apart in cell characteristics.
Dose that sound right!
 
A J said:
Hi eddie1261,
How about this 1.25 + 1.25 = 2.5, and so on, what I think is missing is the 100th of a millivolt?! 0.5 millivolt, 0.05 100th millivolt, 0.005 10th millivolt, 0.0005 ?microvolt? I think microvolt.. added together to get!
Click to expand...

Let's think together.

1.50v for a fully charged AA cell.
1.20v as they sat on my desk.
0.30v

.3 volts missing. 3/10th of a volt, not thousandths. There may be something to consider as far as a +/- factor of the reading on the meter itself, but I checked it on every interval of the meter and on 2 meters. When 1.2 + 1.2 = 2.5 rather than 2.4, that is .1v present when testing 2 of them in series that addition says shouldn't be there.

How did your logic get from volts to millivolts? Thousandths of a volt. This is tenths of a volt. And when it is compounded over 3 and then 4 batteries, the readings were exponentially higher. Factor in that when 4 of them were summed, what I expected to be 4.8 was 5.2, or .4v higher than 1.2 x4. .4v is not thousandths of a volt. It's almost half a volt.

It just has to do with them being in series. Voltage changes, amperage does not with a series connection, correct? This looks like one for someone at Will's level of knowledge. Or Solarvstech maybe. Many people here who know WAY more than I do.
 
eddie1261 said:
Let's think together.

1.50v for a fully charged AA cell.
1.20v as they sat on my desk.
0.30v

.3 volts missing. 3/10th of a volt, not thousandths. There may be something to consider as far as a +/- factor of the reading on the meter itself, but I checked it on every interval of the meter and on 2 meters. When 1.2 + 1.2 = 2.5 rather than 2.4, that is .1v present when testing 2 of them in series that addition says shouldn't be there.

How did your logic get from volts to millivolts? Thousandths of a volt. This is tenths of a volt. And when it is compounded over 3 and then 4 batteries, the readings were exponentially higher. Factor in that when 4 of them were summed, what I expected to be 4.8 was 5.2, or .4v higher than 1.2 x4. .4v is not thousandths of a volt. It's almost half a volt.

It just has to do with them being in series. Voltage changes, amperage does not with a series connection, correct? This looks like one for someone at Will's level of knowledge. Or Solarvstech maybe. Many people here who know WAY more than I do.
Click to expand...

OK, when adding two and two together my thought was the numbers below the 0.01 of the volt, I have dyscalculia, so I can only go so far before I fall over! As for the millivolt thing, to me 0.3 of a volt is 3 millivolt, milli meaning millionth, then thousandth, tenth... I am wrong, not a thousandth, tenth! That's the dyscalculia, imperfections and DIY combined with limited education. Just having a stab at it!
Have a good end of year :).
 
eddie1261 said:
Let's think together.

1.50v for a fully charged AA cell.
1.20v as they sat on my desk.
0.30v

.3 volts missing. 3/10th of a volt, not thousandths. There may be something to consider as far as a +/- factor of the reading on the meter itself, but I checked it on every interval of the meter and on 2 meters. When 1.2 + 1.2 = 2.5 rather than 2.4, that is .1v present when testing 2 of them in series that addition says shouldn't be there.

How did your logic get from volts to millivolts? Thousandths of a volt. This is tenths of a volt. And when it is compounded over 3 and then 4 batteries, the readings were exponentially higher. Factor in that when 4 of them were summed, what I expected to be 4.8 was 5.2, or .4v higher than 1.2 x4. .4v is not thousandths of a volt. It's almost half a volt.

It just has to do with them being in series. Voltage changes, amperage does not with a series connection, correct? This looks like one for someone at Will's level of knowledge. Or Solarvstech maybe. Many people here who know WAY more than I do.
Click to expand...

Here is my guess...

Are these alkaline or nimh?

If alkaline, perhaps in series they are showing closer to the chemistry full charge? 1.65V for an alkaline cell...
 
Alkaline. Cheap ones from Amazon that came in something I bought used. I have Energizers in there now.

I just don't know how they were ALL exactly 1.2, and then they sum to more than 1.2 x 4. 4 of them should be 6v.
 
Sometimes I weigh less about an hour or 2 later, sometimes about 2 lbs. less. I think a lot has to do with electrolytes, i.e., sodium/potassium, balance, how much H2O you drink, etc. Sodium retains water (weight) and drinking a lot of water flushes out water from the cells. EDITED
 
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