AA & AAA Alkaline discharge tests

I have been off work lately, so I decided to kill some time by running some discharge tests on common AA and AAA primaries. I hoped to find out which common brand offered the best performance at the current rates that my lasers demand. *I know that the current draw in the laser can vary, and I also realize that the laser will not load the batteries from fresh until empty as the charger does in testing. The static discharge test is not comparable to real life on/off laser usage. This comparison is mostly just for fun and to give me something to do.


Lasers:

I used fresh alkaline cells in each, and measured the stable current draw with a Fluke 77 with the tailcap removed. The results were odd, considering the PGL-III-A is more powerful than the pen, but also draws less current. ?

CNI 532nm pen – runs on 2xAAA @ 590mA
CNI 532nm PGL-III-A – runs on 2xAA @ 530mA




(the voltage of a random 18650 laying around)


Charger:

The charger I used for discharging is a Duratax Ice (hobby charger, no fancy graphs). I set the discharge rate to .6A for AAA’s and .5A for AA’s, and set the loaded voltage cutoff to 1.1v.




Competitors:

Duracell coppertop
Duracell ultra advanced
Energizer max
Eveready gold




I went into the local home improvement store where I normally buy batteries and picked up a package of each brand in AA and AAA, looking for the freshest date codes possible. The best to be found were all 2016 except for the Energizer Max AAA, which were marked 2017. I checked the voltages of the cells right after taking them out of the package and found the newest cells to have the highest OC voltage (no surprise). Will the freshness give them a loaded performance edge?


Results AAA:

Both Energizer max and Duracell coppertop had cells that fell short under the .6A load. These are likely defects, as I gave them a second chance (an additional discharge cycle) just to see if it might have been a charger error, and none of the retests yielded more than a few seconds of additional runtime (not added into the figures). It is also likely that the current draw is right at the limit of what these cells can do (evident by short runtime and heavily sagging voltage) so if a cell is weak, a moderate load will expose it.

AAA .6A load, 1.1v cutoff


Duracell coppertop
mah avg. voltage
92 1.165
177 1.214
100 1.184
100 1.247

117mah 1.203v

Duracell ultra advanced
mah avg. voltage
206 1.218
226 1.218
209 1.212
227 1.217

217mah 1.216v

Energizer max
mah avg. voltage
165 1.219
177 1.220
77 1.219
170 1.214

147mah 1.218v

Eveready gold
mah avg. voltage
139 1.200
139 1.211
126 1.193
159 1.212

141mah 1.204v


The winner in this test is obvious. If you have a high current draw AAA device, you actually do get more runtime and tighter quality control out of the Duracell ultra advanced product. This was certainly not the result that I expected, but it is what it is. It’s a good feeling to know that in this particular case, you aren’t getting a regular coppertop in a fancy wrapper, sold at a premium price. That is what I was expecting to discover.

The freshness advantage that the Energizer max started with appears to have given it a tiny bit of voltage advantage. Too bad there was a weak cell in the group to drag down the runtime average.



Results AA:

AA .5A load, 1.1v cutoff


Duracell coppertop
mah avg. voltage
798 1.224
909 1.228
834 1.227
904 1.227

861mah 1.227v

Duracell ultra advanced
mah avg. voltage
843 1.241
930 1.237
876 1.236
897 1.238

887mah 1.238v

Energizer max
mah avg. voltage
803 1.221
858 1.218
797 1.209
836 1.223

824mah 1.218v

Eveready gold
mah avg. voltage
677 1.240
763 1.225
700 1.222
779 1.222

730mah 1.227v


Again, the Duracell ultra advanced comes out on top, but it was a much closer race here than in the AAA size.


The main thing that I learned here is that in AAA size alkalines, Duracell ultra advanced is the boss for high draw applications. In AA, I’ll just stick to my regular old coppertops, or Eveready’s if a large enough cost savings is there. I am looking over Energizer max since they are typically exactly the same cost as coppertops and offer lower performance.


Other thoughts:

I’ve read that alkaline batteries ‘recover’ after you let them sit for a few hours or days. Yes, it’s true. These cells that were drained down came back up to almost 1.5v and can fire either laser. (after they’ve been discharge tested and sat for a day). I don’t know how long they’ll run for, I assume not too long, but this could potentially add more runtime to each cell if another test were run today. I am not going to bother with that though.

I did not include Energizer lithium because they are a different chemistry, and a completely unfair competitor. Since Energizer is currently the only company selling lithium primaries, there are no others to fairly compare them to. They would simply kick the crap out of every alkaline on the market, so there is no point in wasting a good cell.

Hopefully something here is useful to someone. I might add other brands later if I get bored again.

So what if they are a different chemistry every one knows this and will take that into account, we want to know the comarison as well as just how much power there is in one of them
are they realy worth $3.00 each ?

Mik said:

I did not include Energizer lithium because they are a different chemistry, and a completely unfair competitor. Since Energizer is currently the only company selling lithium primaries, there are no others to fairly compare them to. They would simply kick the crap out of every alkaline on the market, so there is no point in wasting a good cell.

Hopefully something here is useful to someone. I might add other brands later if I get bored again.

Click to expand...

Flaminpyro said:

So what if they are a different chemistry every one knows this and will take that into account, we want to know the comarison as well as just how much power there is in one of them
are they realy worth $3.00 each ?

Click to expand...

4pks are on sale at Lowes. $10 -$5 MIR, so currently like $1.25/cell after MIR.

I might run one e2 + Ultimate. I am guessing 1.45v avg, 4-5x the runtime of the top alkaline. I saw pictures of your charger, but I don't know anything about it. Does it have a PC link to transfer runtime/voltage graphs? I would like to have the ability to stack the curves like many have done before.

Update:

I put a L92 on the charger with the same specs I had been using for Alkaline AAA. The charger rejected the cell, saying that the voltage is too high for the selections that I chose. (L92 voltage on this particlar cell is 1.800)

I can change settings in the charger so it's set up for 2 cells rather than 1, but it does not offer the ability on 2 cell to stop the discharge at 1.1v. It gives you a setting of cutoff voltage per cell, only down to tenths. I could pick .6v per cell, but I end up cutting off the discharge at 1.2 which would screw up the results.. obviously giving the L92 a higher average voltage and lower runtime. So right now it does not appear that I can run the lithiums on my charger to compare them with the alkalines. I tried!