Calling all Alkaline battery experts

[ChrisGreaves]

No, I'm not trying to recharge old batteries, but I am testing a few sacks of alkaline batteries, AAA, AA and D. Mainly as part of a tutorial exercise in using my cheap Mastercraft MultiMeter which I bought four years ago.

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It's an interesting exercise in logic trying to work out which of nine "9vDC" cells ought to be used in the MultiMeter, but I got there.

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The 6.98v and the 1.03v were cobbled together and delivered 8v as I predicted (1.08 + 6.98 delivered 8.01v)
I had already determined that any dry cell above 6.98 in my multimeter delivered consistent results.
My current theory is that IF I run out of suitable 9v cells, in an emergency I could rig up two or more weak cells in series and that should work.
Correct?
I had already tried four "1.3v" D cells in series to obtain 5.7v, which is pretty close to 6v, so I guess that the bulb on the big torch is gone.

Now I am about to test 13 AAA cells and 19 AA cells, one by one as a mind-numbing relaxation technique (grin), and I suppose that the same reasoning applies: that wiring a half-dozen weak AAA cells in series is a viable alternative to buying new AAA cells or recharging existing rechargeable AAA cells.
Correct?

Thanks, Chris

[Jay Freedman]

The addition of voltages of cells in series is valid.

The scheme has the same drawback as the old Christmas light strings of bulbs in series: If one unit goes dead (dried-out or otherwise disabled), the whole chain dies.

[GeoffW]

The addition of voltages of cells in series is valid.

The scheme has the same drawback as the old Christmas light strings of bulbs in series: If one unit goes dead (dried-out or otherwise disabled), the whole chain dies.

So this must be the "current theory" that Chris referred to?

[ChrisGreaves]

The addition of voltages of cells in series is valid.

Thank you, Jay. I miss my Physics teacher, Mister Puzey.

9vDC	6vDC	1.5vDC	AAR	AAU	AAAR	AAAU
1.03	2.00	1.30	1.25	1.54	1.25	1.57
4.29	-	1.30	0.19	1.38	1.26	1.58
7.90		1.30	1.26	1.30	1.26	0.84
8.07		1.30	1.26	1.39	1.26	1.55
6.98			1.25	0.82	1.26	1.36
8.79			0.55	0.51	1.26	1.35
9.00			0.71	1.52	1.24
9.29			1.25	1.41
9.00			1.24	1.54
			1.22	1.27
			1.02
64.35	2.00	5.20	11.20	12.68	8.79	8.25	112.47

I now have 112 vDC at my command, and must go back to basics. The voltage is not the only thing that counts, but fascinating. House voltages here are 110-120v. This total includes rechargeable cells, which, when fully charged, might increase that total.

The scheme has the same drawback as the old Christmas light strings of bulbs in series: If one unit goes dead (dried-out or otherwise disabled), the whole chain dies.

Quite so. But in that case my application would give a signal if only by going Dead.
Until I began sticking marked tape onto cells yesterday I had no idea what was usable and what was garbage destined to be broken open and usable material components recovered.

All of this is aimed towards my 12vDC wind turbine project, started three years ago, but stalled while I gardened.
Thanks again
Chris

[ChrisGreaves]

So this must be the "current theory" that Chris referred to?

Nah! I ripped my canes out last year.
Chris

[Graeme]

If you put enough batteries in series to give you 112V across the end terminals then you will probably be able to pull enough current to cause the batteries to explode!

Graeme

[ChrisGreaves]

If you put enough batteries in series to give you 112V across the end terminals then you will probably be able to pull enough current to cause the batteries to explode!

Thanks Graeme. Why is that/Why didn't I think of that?
Is it because I am testing voltages, I thought only of adding voltages?
I know that current (measured in amperes) is flowing through the circuit at what I think of as the pressure/voltage.
Each battery is built to deliver/withstand a specific current, but when they all gang up the combined current will be x-times stronger/more powerful than the individual batteries can withstand?

One large flashlight has four D cells, 1.5v each, in series, so presumably each D-cell can withstand four times its current?

I should find myself a basic high-school physics book and study it for a few weeks, is my bet.
Cheers, Chris
Minutes later:) I found a PDF textbook at https://openstax.org/details/books/physics and can start reading first thing tomorrow morning!

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C.

[Graeme]

I have to admit I'm guessing a bit here because I've never put enough batteries together in series to produce a voltage of 112V. Although I have put 20 x 12V batteries together in an HV substation switchgear control supply battery charger.

But suppose you have a 1000W heater across your 112V.

Then I = P/V = 1000/112 = 8.93A

Those batteries would probably get very hot with almost 9A flowing through them!

But then suppose you have a 100W light bulb across your 112V.

Then I = P/V = 100/112 = 0.893A

I expect they would handle that, perhaps I was worrying too much!

Graeme

[ChrisGreaves]

I have to admit I'm guessing a bit here because I've never put enough batteries together in series to produce a voltage of 112V.

Graeme: To the great surprise of all of us, neither have I! So far I just did primary school arithmetic - addition using pencil and paper.

But suppose you have a 1000W heater across your 112V.

It just so happens that I have such a heater element sitting on my bathroom floor.
Also that downloaded Physics text book.
So I shall study the text book, work through your example (thank you!)

Those batteries would probably get very hot with almost 9A flowing through them!

And I suppose that if I ran the current for One Second they should be warm to the touch; a trial for another day week.

But then suppose you have a 100W light bulb across your 112V.

This too deserves examination of the text book. Tomorrow, I promise.

I am testing batteries(cells) because I figured that they were individually harmless as i explored my cheap multi-meter. The multi-meter seems to protect itself when I dial the wrong setting, so I suppose I am still safe in isolation.

And all of this is leading to installation of the 12vDC turbine I bought three? years ago.
My main fear is that I will forget to "twist the bare ends of the three wires together" until the doo-dad controller that lies between the turbine and the storage battery is hooked up. At the rate I'm going that will be before the next Canadian solar eclipse following April 8th.

I am grateful for you, once again, diverting me onto the path of looking things up!
Thanks, Chris