Battery Energy Notes 2

Original research by Peter G Halverson, Ph.D. https://halverscience.net/battery_energy/

Run #, date, time: 14, 12/30/2020,

Battery #: 11

Brand, size, type: Energizer AAA, Ultimate Lithium

Price: $2.00

Weight: 7.8 g

Sample time: 10 s

Load R: 14.5 Ohms to ground

No-load voltage at start: 1.80 V

Voltage with load at start: 1.35

Run duration: 62430 s

No-load voltage at end: 0.418

Voltage with load at end: 0.214. (Curious "bounce" in voltage. See graph.)

Energy (from program, no corrections):

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Analysis:

Current and power integrated from t=160 to t=48380 s.

Conversion: 4236 Amps-s = 1.177 Amp-hours

Run #, date, time: 15, 1/2/2021, 4:55 PM

Battery #: 12

Brand, size, type: Duracell Optimum, AAA, Alkaline

Price: $1.25 (I bought a pack of 8 for $9.98 at Home Depot 1/2/2021)

Note: Two of the batteries were leaking. (Package has a 2019 copyright.)

Weight: 10.9 g

Sample time: 10 s

Load R: 14.5 Ohms to ground

No-load voltage at start: 1.669 V

Voltage with load at start: 1.43 V (dropping)

Voltage with load at end: 0.136 V

Energy (from program, no corrections): 3534 J

No-load voltage at end: 1.01 V (rising)

Run duration: 57900 s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Analysis, using 14.5 Ohms load:

Conversion: 2865 Coulombs = 0.796 Amp-hours

Run #, date, time: 16, 1/3/2021, 10:25 AM

Battery #: 13

Brand, size, type: Duracell (no special name, MN2400) "Guaranteed 10 years" AAA, Alkaline.

Expiration date Mar 2030.

Technical data from Duracell can be found here: https://www.duracell.com/en-us/techlibrary/product-technical-data-sheets/

Price: $1.16 (I bought a pack of 6 for $6.98 at Home Depot 1/2/2021)

Weight: 11.6 g

Sample time: 10 s

Load R: 14.5 Ohms to ground

No-load voltage at start: 1.615 V

Voltage with load at start: 1.37 V (dropping)

Voltage with load at end: 0.175 V

Energy (from program, no corrections): 3565 J

No-load voltage at end: 1.19 V (rising)

Run duration: 47710 s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Analysis:

Energy: 3498 Joules. Charge: 3167 coulombs.

Conversion: 3167 Coulombs = 0.878 Amp-hours

Interesting to compare my measurement with similar measurements by Duracell. Here is a graph from their datasheet:

My data, using 14.5 Ohms should fall between their 10 ohm (violet) and 24 ohm (green) curves. Their analysis cut-off is at 0.9 Volts.

My data reaches 0.9 V around 40000 seconds. Their data reaches 0.9 V around 14 hours or 50000 seconds, where I'm splitting the difference between the 10 and 24 ohm curves.

Hence they claim a 25% longer life for the battery than what I measured.

Run #, date, time: 17, 1/4/2021, 10:20 PM

Battery #: 14

Brand, size, type: Energizer Industrial, AAA, Alkaline. Expiration 12/2029

Price: $ 0.69 Ordered 12/29/2020 from Jameco Electronics. Part number 198715.

Note that expiration date on battery says 12-2029

Weight: 11.8 g

Sample time: 10 s

Load R: 14.5 Ohms to ground

No-load voltage at start: 1.583 V

Voltage with load at start: 1.37 V (dropping)

Voltage with load at end: 0.104 V

Energy (from program, no corrections): 3337 J

No-load voltage at end: 8.87 V (rising)

Run duration: 54010 s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Analysis

Conversion: 3015 Coulombs = 0.8375 watt-hours

Run #, date, time: 18, 1/5/2021, 7:41 pm

Battery #: 15

Brand, size, type: Evergreen AAA, Alkaline.

Price: $ 0.45 Ordered 12/29/2020 from Jameco Electronics. Part number 2112436

Weight: 11.2 g

Sample time: 10 s

Load R: 14.5 Ohms to ground

No-load voltage at start: 1.596 V

Voltage with load at start: 1.39 V (dropping)

Voltage with load at end: 0.128 V

Energy (from program, no corrections): 3422 J

No-load voltage at end: 1.095 V (rising)

Run duration: 60640 s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Analysis:

Conversion: Q=2908 Coulombs = 0.808 amp-h

RECALIBRATION OF AAA Alkaline measurements done up to this point.

I deleted the 1/6/2021 corrections page as I had already gone back and put the 14.5 ohms into the analysis software. Hence my corrections were redundant.

ALL RUNS GOING FORWARD ARE ON MY IMPROVED SETUP USING RELAYS AND ACCURATE RESISTANCES. (Previous data have some calibration problems that I can't completely untangle.)

Run #, date, time: 19, 1/12/2021, ?

Battery #: 1

Brand, size, type: Ikea Ladda AAA, Nimh. Capacity = 500 mAh = 0.5 Ah

This run is mainly to test my new software and hardware. I'm deliberately overcharging the battery at the end to see what effect that has.

Price: $ Don't know

Weight: 9.4 g

Sample time: 10 s

Load R: 15.00 Ohms to ground

Charging R: 30.00 Ohms to +5.00 Volts

No-load voltage at start: x V

Voltage with load at start: x V (dropping)

Voltage with load at end: V

Energy (from program, no corrections): J

No-load voltage at end: V (rising)

Run duration: s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Bottom curve indicates relay action. 0=relays off. 0.1=discharging relay on. 0.2=charging relay on.

Next graph shows charge in (horizontal axis) vs charge out (vertical axis). A perfect battery would have a straight line since in theory Q_out = Q_in.

That this battery is labeled "500 mAh", so it makes sense that it doesn't work so well when Q_in is more than 0.5 Ah. Note that the battery did work OK, even when overcharged by a factor of two (1.0 Ah).

Data for this graph

Q in ..................... Q out

0.0421170254021 0.0420945668478

0.0531710154541 0.0526047622096

0.0668311667441 0.0662807099084

0.0841240960533 0.083660187799

0.105719895956 0.105007055359

0.133233912064 0.132552016324

0.167683526624 0.166483766481

0.211205416791 0.209022027956

0.265777535689 0.261963952766

0.334632339207 0.326182071307

0.420788439447 0.401224929185

0.528892779839 0.468462524836

0.665146935388 0.500299496877

0.830912238652 0.515753292333

1.05067485665 0.525365180546

1.35010871522 0.272139325105

Next graph shows energy in (horizontal axis) vs energy out (vertical axis). A perfect battery would have a straight line since in theory E_out = E_in. In real life, the energy out is always less because the battery's internal resistance converts some energy to heat.

Data for this graph:

E in .................. E out

210.717375957 185.656434796

265.721734895 234.487606739

334.648261302 297.579038161

422.321807199 378.176466534

532.071544822 476.932851556

672.702421067 604.437891886

849.110601724 761.244045595

1070.302847 958.065034394

1350.82893081 1202.01442968

1703.96855847 1496.22050997

2153.18525674 1836.28523612

2722.05368917 2140.46843448

3439.24390227 2275.54275252

4385.18517805 2314.35954408

5497.67736035 2376.1965694

6724.83120319 1224.99173906

Run #, date, time: 20, 1/13/2021, ~9 pm

Battery #: 16

Brand, size, type: Duracell Optimum, AAA, Alkaline. This is a re-test to see if I get close to the results as before. Battery came from same package.

Price: $ 1.25 (I bought a pack of 8 for $9.98 at Home Depot 1/2/2021)

Weight: 10.9 g

Sample time: 10 s

Load R: 15.00 Ohms to ground

No-load voltage at start: x V

Voltage with load at start: x V (dropping)

Voltage with load at end: V

Energy (from program, no corrections): J

No-load voltage at end: V (rising)

Run duration: s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Analysis

The above analysis and my improved data-taking software give the same results

Charge from the battery = 3015 coulombs = 0.8375 Ah

Energy from the battery = 3900 J

Previous Duracell Optimum results: Run 15, Q=2865 C=0.7958 Ah E=3347 J

Average Q=(0.8375+0.7958)/2=0.8150 Ah Averrage E=(3900+3347)=3623.5 J

Run 21, date 1/16/2021, time:

Battery #: 17

Brand, size, type: Energizer Max AAA, Alkaline. Re-test to see if new setup agrees with old. Battery came from same package.

Price: $

Weight: 10.6 g

Sample time: 10 s

Load R: 15.00 Ohms to ground

No-load voltage at start: 1.618 V

Voltage with load at start: 1.526 V (dropping)

Voltage with load at end: 0.750 V (Software is set to end run when it reached 1/2 of nominal, which is1.5/2)

Charge (from program, The integral of I=V/R while load R was applied): 3861.0 C = 1.0725 Ah

Energy (from program, The integral of P=V*I while load R was applied): 4643.5 J

No-load voltage at end: 1.109 V (rising)

Run duration: 50120 s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Analysis:

Conversion: 3860 C = 1.0722 Ah

Run 22, date 1/17/2021, time: 9:30 pm

Battery #: 18

Brand, size, type: Rayovac High Energy Alkaline. "10 Year Guarantee" Expiration date 2030

Price: $

Weight: 10.9 g

Sample time: 10 s

Load R: 15.00 Ohms to ground

No-load voltage at start: 1.617 V

Voltage with load at start: 1.548 V (dropping)

Voltage with load at end: 0.750 V (Software is set to end run when it reached 1/2 of nominal, which is1.5/2)

Charge (from program, The integral of I=V/R while load R was applied): 3901.8 C = 1.0838 Ah

Energy (from program, The integral of P=V*I while load R was applied): 4464.5 J

No-load voltage at end: 1.119 V (rising)

Run duration: 52160 s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Run 23, date 1/18/2021, time: 10:55 pm

Battery #: 19

Brand, size, type: Kodak Xtralife Alkaline. Re-test to compare with run 13. Expiration 8/2030

Price: $

Weight: 11.4 g

Sample time: 10 s

Load R: 15.00 Ohms to ground

No-load voltage at start: 1.610 V

Voltage with load at start: V (dropping)

Voltage with load at end: 0.750 V (Software is set to end run when it reached 1/2 of nominal, which is1.5/2)

Charge (from program, The integral of I=V/R while load R was applied): 4235.6 C = 1.1766 Ah

Energy (from program, The integral of P=V*I while load R was applied): 4840.2 J

No-load voltage at end: 1.038 V (rising)

Run duration: 59530 s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Run 24, date 1/19/2021, time: 5:05 pm

Battery #: 20

Brand, size, type: Energizer Max Alkaline. 2nd re-test.

Price: $

Weight: ? g

Sample time: 10 s

Load R: 15.00 Ohms to ground

No-load voltage at start: V

Voltage with load at start: V (dropping)

Voltage with load at end: 0.750 V (Software is set to end run when it reached 1/2 of nominal, which is1.5/2)

Charge (from program, The integral of I=V/R while load R was applied): 3881.6 C = 1.0782 Ah

Energy (from program, The integral of P=V*I while load R was applied): 4663.0 J

No-load voltage at end: 1.144 V (rising)

Run duration: 54070 s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Recheck resistance battery sees when discharge relay is on: 15.01 Ohms.

Method: Remove battery. Turn on the discharge relay. Put Fluke 87 V multimeter into high resolution mode.

Short the meter probes and enter "REL DELTA" mode which causes it to remember and subtract out the meter probes' resistance. Then measure the resistance by putting the probes on the battery holder contacts.

I consistently get readings within +/- 0.02 of 15.00 ohms.

While I'm at it, check the ADC. The Fluke meter and ADC agree to 2 mV. I.e. when the meter reads 1.609 V (at the battery holder terminals), the ADC says 1.607 V.

Run 25, date 1/20/2021, time: 9:25 am

Battery #: 21

Brand, size, type: Duracell (no special name) MN2400 Alkaline. Re-test. Compare to run 16, batt 13.

Price: $

Weight: 11.5 g

Sample time: 10 s

Load R: 15.00 Ohms to ground

No-load voltage at start: 1.608 V

Voltage with load at start: 1.529 V (dropping)

Voltage with load at end: 0.750 V (Software is set to end run when it reached 1/2 of nominal, which is1.5/2)

Charge (from program, The integral of I=V/R while load R was applied): 3505.7 C = 0.9738 Ah

Energy (from program, The integral of P=V*I while load R was applied): 4317.1 J

No-load voltage at end: 1.237 V (rising)

Run duration: 52020 s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Run 26, date 1/21/2021, time: 8:50 AM

Battery #: 22

Brand, size, type: Energizer Industrial, Alkaline. Expiration date 12/2029

Price: $

Weight: 11.7 g

Sample time: 10 s

Load R: 15.00 Ohms to ground

No-load voltage at start: 1.582 V

Voltage with load at start: 1.532 V (dropping)

Voltage with load at end: 0.750 V (Software is set to end run when it reached 1/2 of nominal, which is1.5/2)

Charge (from program, The integral of I=V/R while load R was applied): 3370.2 C = 0.9362 Ah

Energy (from program, The integral of P=V*I while load R was applied): 4054.5 J

No-load voltage at end: 1.212 V (rising)

Run duration: 51310 s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

Run 27, date 1/22/2021, time: 9:20 AM

Battery #: 23

Brand, size, type: Evergreen (from Jameco) re-test AAA Alkaline.

Price: $

Weight: 11.2 g

Sample time: 10 s

Load R: 15.00 Ohms to ground

No-load voltage at start: 1.595 V

Voltage with load at start: 1.517 V (dropping)

Voltage with load at end: 0.750 V (Software is set to end run when it reached 1/2 of nominal, which is1.5/2)

Charge (from program, The integral of I=V/R while load R was applied): 3476.2 C = 0.9656 Ah

Energy (from program, The integral of P=V*I while load R was applied): 4078.6 J

No-load voltage at end: 1.163 V (rising)

Run duration: 53890 s

Raw data, vertical axis=battery voltage, horizontal axis=time, in seconds.

CONTINUES IN NOTEBOOK 3

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