What Battery Brand Provides Power the Longest?

In this age of ubiquitous electronics, batteries have an astounding importance in our everyday lives. As we buy and use different brands, we come to wonder, "Which of these is actually the best? Is it worth it to go for a big name brand?" To answer these questions, I set up an experiment to test the endurance of four different battery brands: Duracell, Energizer, Rayovac, and Sunbeam(a dollar store brand).

Step 1: The Materials and the Hypothesis

To test the comparative endurance of the four battery brands under study, I used four Mini Maglite xenon lamp flashlights purchased from Walmart on the same day. As for batteries, I bought an eight pack of Energizer AA batteries, an eight pack of Rayovac AA batteries, and a four pack of Sunbeam dollar store AA batteries. The flashlights came with Duracell, so I used those batteries for the Duracell test. I did, however, find a price for a Duracell eight pack in order to compare prices more effectively in the conclusion.

My hypothesis was as follows: Dollar store batteries will be the first to go, with one of the bigger name brands coming out on top. I had no basis for distinguishing between the three top brands, but because the Duracells came with the flashlights, indicating that they might be preferable, I hypothesized that Duracell would last the longest.

Step 2: The Setup

To carry out the actual test, I prepared an apparatus that would hold the flashlights parallel to one another, all shining on one piece of cardboard so their relative intensities could be observed. I put two Sunbeam batteries in the top light, two Duracells in the second, two Energizers in the third, and two Rayovacs in the fourth.

Step 3: Starting the Test

To start the flashlights, I went from top to bottom, twisting the top of each light until the exact point at which the light turned on (the flashlights were turn-top instead of push-button. Button flashlights may be more useful in future experiments). In all, going from Sunbeam to Duracell to Energizer to Rayovac took 13 seconds.

Step 4: After 1 Hour

After one hour, all four lights were shining brightly, with no apparent difference in intensity from one brand to another.

Step 5: After 2 Hours

After two hours, the relative brightness of each light remained pretty much the same.

Step 6: After 3 Hours

After three hours of constant shining, still no significant change.

Step 7: After 4 Hours

Here's where things started to get interesting. After four hours of shining, all four lights were still lit, but Sunbeam (the dollar store brand) was starting to show slight signs of weakness.

Step 8: After 5 Hours

The Sunbeam was, indeed, the first brand to fail, providing no more light at precisely 4 hours and 50 minutes. The five hour picture shows the three remaining brands, with Energizer starting to look a little bit dim.

Step 9: Sunbeam Bulb Test

In order to determine that the failing of each flashlight was due to the batteries dying and not the bulbs burning out, I took out the batteries from the dead flashlight and replaced them with fresh Duracells. The results show that the bulb still worked quite well, verifying that the batteries' losing power was the reason for the light going out.

Step 10: At 5 Hours and 9 Minutes

I interrupted the regularly scheduled hour-increments because Energizer seemed quite close to going dead. I prepared for a picture at five and a quarter hours, but took this picture at 5h 09m to show the dimming Energizer.

Step 11: At 5 Hours and 15 Minutes

By the time 5h15m finally rolled around, Energizer was fully depleted.

Step 12: Energizer Bulb Test

As I did with the Sunbeam light, I took out the Energizer batteries and replaced them with fresh Duracells to check on the working status of the bulb. It's function was still maximal.

Step 13: After 6 Hours

After six hours, even the strongest two brands were significantly dimmed, with Duracell a good bit dimmer than Rayovac.

Step 14: After 6 Hours and 5 Minutes

At 6h5m, the Duracell batteries were pushing out the very last bit of power they could muster, showing a bright spot a fraction of the size of the beam cast by the Rayovac-powered light. It is worth noting here that the Duracell flashlight seemed to take longer to fully go out than the others, remaining persistently dim for an extended period of time, finally going out by 6h10m.

Step 15: Duracell Bulb Test

In the time it took me to prepare the Duracell flashlight for the bulb test, the Rayovac light was significantly dimmed. The Duracell bulb performed well with fresh batteries, just as those before it.

Step 16: After 6 Hours and 12 Minutes

Rayovac was the last flashlight to go out, dying at 6h12m.

Step 17: Rayovac Bulb Test

Finally, I performed the switch from spent Rayovac to fresh Duracell for the last flashlight, demonstrating the continued effectiveness of the Rayovac flashlight's bulb.

Step 18: Conclusions - and the Winner Is...

Observing the times of battery death for the four tested brands, the results are as follows:

1-Sunbeam = 4h50m

2-Energizer = 5h19m

3-Duracell = 6h10m

4-Rayovac = 6h12m

As hypothesized, the dollar store brand was the first to die, and contrary to the hypothesis, Rayovac lasted the longest shining time, beating Duracell by only a couple of minutes.

Dividing the price of the battery pack by the number of batteries in each pack, I calculated the price per battery for each brand:

Sunbeam = $0.25/battery

Energizer = $0.79/battery

Duracell = $0.80/battery

Rayovac = $0.62/battery

Dividing the price of two batteries by the time during which they provided power gets the price per hour of battery power.

Sunbeam = 10 cents/hr

Energizer = 30 cents/hr

Duracell = 26 cents/hr

Rayovac = 20 cents/hr

Based on these results, Sunbeam batteries provide the most power for their price. However, as they provide power for the shortest time, the necessity of frequent battery changes may decrease the value of the batteries in terms of convenience. I would argue that Rayovacs are the best buy because they provide power for the longest time with a comparitively low price, even if they only come in second on the price/power lineup.

Step 19: Worth a Note:

While the results of the experiment are clear, interpreting them can only go so far. The batteries may perform differently in different devices, and the relative duration of power supply may differ if the flashlights are turned off for a period of time and then turned back on. For each light, after going out, turning off the light and turning it back on a few seconds later would yield a small beam of light, although this beam only lasted a short time before going out again. These factors would be an interesting topic of study for future experiments.

Thanks for reading!

Step 20: Contest

If you haven't already, please vote for my experiment in the Scientific Method Contest! I really appreciate all of the compliments and suggestions from everyone who's already viewed - if you could help me out in the contest, I would be very grateful!