Weird AA battery problem

[CK2]

Trying to figure this one out... I've been doing a comparison test all day of a set of "Pure Energy" vs. Energizer AA rechargeables. Both battery brands will power my digital camera. However, my four AA Duracell 2650mah (green & black) rechargeables will no longer power my camera. I've tried everything... charging and discharging them in a good quality Radio Shack pulse charger. Charging 4 at a time, then 2 at a time. When I did 2, the RS charger said they were 1.44v.

What's the problem here?

- For those who might say it's the camera: The batteries were tried in two digital cameras: a 2-cell Sony (it starts for half a second every time, when I insert the Duracells), and a 4-cell Fujifilm (it has never even come close to starting when these batteries are inserted).

- For those who might say it's the voltage: I checked their voltage, I'm getting anywhere from 1.38v to 1.44v on the 4 batteries. The Pure Energy batteries registered well lower than the Duracells. Yet they started fine in both cameras.

- For those who might say it's the contacts: I cleaned them thoroughly with a rag soaked in vinegar, then a water wash, then dry. No change. Also, the Duracells work perfectly fine in my flashlight. If it were the contacts, it would not.

- For those who might say the battery is bad: there is no indication of swelling or oxide leakage from the battery.

- For those who might say its the charger: I also tried charging the Duracells in the Pure Energy charger. No change.

 

[hwc]

The Duracell 2650s (which are the same Japanese made Sanyo batteries as the PowerEx 2700s and Sanyo 2700) are notorious for that exact kind of failure. Seem to charge fine, voltage measures fine, but they either won't turn on a camera or will die after three or four flashes. About half of mine (I have had all three brands) have failed like that. It's been a real hassle just trying to identify the bad sets and get rid of them. Needless to say, I'm not real confident in any of these batteries at this point, although I still have five or six sets of 4 -- Walmart used to sell 8 packs of the Duracell branded Sanyos for $15.95, which was a pretty sweet deal, until they started croaking right and left.

In order to get higher and higher capacities, they had to go to thinner and thinner materials so they could roll up more stuff and shove it into the battery. I believe that the jump from 2300 to 2500/2700 maH resulted in separators that were so thin, they were suspectible to internal shorts -- maybe even from dropping the battery. Whatever the cause, these high capacity batteries have proven to be extremely unreliable. I believe the high failure rates probably pushed Sanyo to back the truck up and start marketing reliable technology in the form of low-self-discharge eneloops, which appeared in the market about the same time these high capacity batteries were dominating the market.

My advice: If you charge a set of these Duracell 2650 or Sanyo 2700 or Powerex 2700 (or Energizer 2500) batteries and they die immediately in the camera, just get rid of that set so it won't continue to drive you postal. You'll go crazy trying to figure out which one is the "bad" cell.

Energizer replaced their 2500 battery with the new 2300 maH battery which seems to work really well. As far as I can tell, that is also a Japanese made Sanyo battery. The battery makers got much better reliablity and lower self-discharge by going back to slightly thicker more robust materials, even though it meant reducing the capacity. Frankly, you'll get much better real-world performance from a 2000 maH Eneloop than from a 2700 mah battery that looses half its charge in three days do to a bad cell.

In AAs, I've accumulated 12 of the Energizer 2300s and 12 of the Japanese made Duracell-branded Eneloops, so I have pretty much stopped using the 2700s. In AAAs I have nothing but Eneloops and Japanese made Duraloops, except for one set of Sanyo 1000 maH batteries that seem to work.

 

[CK2]

Thanks for your response, hwc. After further reading around here, I was starting to get that impression. I also found I wasn't the first to experience this from the Duracell's, so that must be the answer. What a shame. Like others, I went out of my way to get these because I thought they were the best quality. I bought them because I was underwhelmed by the performance I was getting from my silver Energizer 2500's. I found the Duracell's, at least for the time they worked, to be better performing. Now I can't use them for what I bought them for, and have to relegate the 2650's to flashlight use. (I only have 4 of these, and they're all "the bad cell". So I'll know not to use them in a camera).

I am getting smarter though, and after reading some posts here, I'm getting out of the "mah race", and will stick to more reliable 2000's in the future. Hence, after researching replacements for the best AA rechargeables on the market, I just ordered a couple of 4-packs of Eneloops off of eBay. I've never tried them but I'm fully confident they'll be satisfactory (and that they're not fakes).


BTW, if anyone's interested... I just finished the test and the results of my Pure vs. Energizer test shows that the Energizer's outperform. Though I'm sure that doesn't surprise anyone...

Camera: Sony DSC-HS5

Batteries:
============

Pure+ Energy (1200mah LSD AA battery)
(Claims good for up to 500 uses and up to 5000 pictures per charge)
(comes with "ready charger", purchased at Wal-mart)

Results: Took 80 flash photos, and 3 mpeg videos, totalling: 41min 40s.

Energizer (2500mah non-LSD AA battery):

Results: Took 80 flash photos, and 4 mpeg videos, totalling: 96min 46s.

 

[hwc]

The shame of it is that the Sanyo made 2700s (inc. the PowerEx 2700 and Duracell 2650) were considered to be the absolute highest quality NiMH on the market. When they work, they are fantastic. But, unfortunatey, less has proven to be more. Reliably delivering 2000 maH is better than hit or miss with a little more juice.

It makes sense when you think about it. There are very few applications where we really squeeze every last bit out of a battery. How often do we take 500 photos? Or run a flashlight non-stop for hours? Usually, it's better to have a battery that holds its charge and is ready to go when you need it.

I think that the eneloop is taking all the materials technology that went into the high capacity batteries (the superlattice alloy electrodes and so forth) and using it in a more conservative design with thicker electrodes, thicker separators, etc. In other words, using the materials technology to provide low self discharge and rugged reliability instead of the highest possible capacity. When the much lower capacity eneloops were introduced, it didn't make a lot of sense, but now it does. To have a battery that you can leave charged in a camera or a flashlight and count on it to work several months later is a real advance.

 

[shadowjk]

Probably if you were to test these failing batteries, they'd either have low capacity, or have high internal resistance resulting in very low usable capacity at moderate drains like 2Amps or more..

 

[RCM]

I have 3 of the Duracell 2650s here as well, and one of them shows a closed circuit voltage of 0.12 volts even when just taken off the charger! I still have 2 that seem to work ok...I have 4 2300 sanyo/energizers and 2 2450 Sanyo/Duracells. There were 4 of them, but they got incredibly hot, too hot to touch (no idea what happened there!)

 

[45/70]

Just thought I'd mention that if good quality high cap NiMh cells are used at low to medium discharge rates, they actually perform quite well. It is when they are subjected to moderate to high discharge rates that they tend to fail prematurely. Still, as has already been mentioned, due to the thinner separator used in high cap cells, they are subject to damage from rough handling, such as dropping or impact. They are much more fragile in this regard.

Dave