AA Rechargeable Battery Test

I've been following a channel on YouTube called Project Farm for a few weeks now and he just posted a test of readily available rechargeable AA batteries. Nice thing about this guy's videos is that he doesn't waste any of your time!

Anyway, here's the link -

I bought a bunch of Sanyo Eneloop batteries (both AA and AAA) in 2010 and they still work OK though I never used the AAs much for photography. I had some overexposure issues using 8 Eneloops with one roll of slide film in a Nikon F5. The AAAs are still working great in blinky lights for cycling.

Anyway, (spoiler alert) Harbor Freight came out on top in this guy's testing, though he didn't end up recommending them because Harbor Freight can be hit or miss on some products. If on-site reviews are believable, they are indeed a good choice.

Eric Sande

AA batteries are used in many shoe flashes.

And if you use flash(es) a lot, you will be using rechargeable batteries.

What was not clear in the video (at least I did not hear it) is how many batteries of each make/model he tested. One battery is not a proper sample to predict the population of that battery. Sample variation could lead to different numbers for each battery. There is a whole discipline of statistical sampling, to determine the number of items to sample to represent a population.

A better test for him, would have been to test 4 batteries of a make/model at once, and note the numbers for each of the 4 batteries, and see how tight or loose the numbers are. Which gives some idea of how consistent the batteries are. While 4 batteries is still too small to be a statistical sample, it is better than 1 battery.

IOW, while interesting, it is a flawed test, because the sample size of ONE battery is way too small to represent the population of that particular battery.

And to test his measuring device, he would need to test the same battery in each of the 4 charging positions. And the result should be essentially the same numbers in each position. And this should be done with several different batteries at each of his charge/discharge rates.

One thing about store brand batteries (Ikea, Harbor Freight, etc.), is that you do NOT know who the manufacturer(s) is/are. Yes, "are." They could buy batteries from several different manufacturers, and have them packaged under their store name in identical packaging. As far as the store is concerned, it is the same SKU (stock keeping unit) and has the same UPC number. That it comes from different manufacturers is not relevant. Your only clue is if one says "made in China" and another says "made in India." But you have no clue if the batteries are made by different manufacturers in the same country.

I get the four for a dollar alkaline AA's The Dollar Tree and I really can't see any difference in performance between them and the Copper Tops.

How long did they last v. the copper top?

I think it's worth a little more to buy name brand Eneloop batteries. As noted above, they last a long time, and seem to hold their charge.

One word of caution. They sometimes show errors when charged in a high-quality charger, namely a Powerex Maha 800. Never cycle the batteries (charge-discharge-charge) in this device. You will toast the charger and batteries, possibly cause a fire (the batteries and charger ends up swollen and charred). Eneloop batteries seem to have a higher voltage, 1.44 V, than standard NiMH batteries (1.325 V), which can confuse the charger.

Powerex does make a conditioning charger, model MH-C9000, which will charge, renew and test Eneloop batteries, showing the capacity in mAH.

Only chargers which treat each battery individually should be used. Otherwise, the strongest battery determines the maximum charge, while the weakest battery determines the useful charge life. Eventually half of your batteries will be under-capacity.

How long did they last v. the copper top?

Eneloop Pro batteries have a capacity of 2400-2500 mAH, compared to about 2700 mAH for alkaline batteries. However they can be recharged over 1000 times, making their use both economically and ecologically advantageous. Unlike conventional NiMH batteries, which loose about 10% of their charge in a week, Eneloop batteries retain up to 85% of their charge in a year.

On the downside, NiMH batteries hold their voltage almost to the end of their charge, then fail like turning off a switch. Alkaline batteries fail gradually, giving you a grace period of lower performance. On the plus side, NiMH batteries have low internal resistance, and can handle high loads better than conventional batteries.

Eneloop Pro batteries have a capacity of 2400-2500 mAH, compared to about 2700 mAH for alkaline batteries. However they can be recharged over 1000 times, making their use both economically and ecologically advantageous. Unlike conventional NiMH batteries, which loose about 10% of their charge in a week, Eneloop batteries retain up to 85% of their charge in a year.

 

On the downside, NiMH batteries hold their voltage almost to the end of their charge, then fail like turning off a switch. Alkaline batteries fail gradually, giving you a grace period of lower performance. On the plus side, NiMH batteries have low internal resistance, and can handle high loads better than conventional batteries.

I switched from using alkaline batteries to using NiMH batteries in my hotshoe mounted flash because the increase in internal resistance in the alkaline batteries as they discharged made their recharges of the flash increasingly slow. The flash recharges very quickly when using the NiMH batteries, until the NiMH batteries' charges are depleted.