Rayovac 4.0 Discharge Testing

[beamis]

I couldn't find any real data on the inexpensive Rayovac 4.0 AA batteries. We all know they're not going to come anywhere near the performance of an Eneloop, but can we quantify? Here's the result of a test I did this morning with 4 Rayovac 4.0 AA batteries hot off the MAHA C-401FS charger and into the C9000 for a 1000 mA discharge. The batteries had been slow discharged at 100 mA and subject to a "break-in" cycle on the C9000 before being run down again at 400 mA and then charged on the C-401FS.

I discharged all 4 batteries simultaneously and averaged the voltage from all four at each reading. I recorded the voltage every few minutes and graphed the result in Excel. I'm working on other discharge rates.

 

[ltiu]

Good one. Thanks.

 

[Niconical]

A good clear chart, thank you for putting in the time and effort, these things are always appreciated

 

[Vikas Sontakke]

Great chart! Has anbody posted similar chart for Eneloop?

- Vikas

 

[beamis]

I intend to graph a 500 mA discharge and also graph Eneloops on the same regimen for comparison tonight when I get home.

I also intend to conduct a self-discharge test on these batteries. Since they're only $1 each, they are certainly worth something. I plan on using them for my weather stations, clocks, remote controls, and other low-drain non-critical devices.

According to this thread, the Rayovac 4.0 performs at 1000 mA the way the Eneloop does at 3000 mA output in terms of voltage.

 

[Conan]

Great chart! Has anbody posted similar chart for Eneloop?

- Vikas

Could this contain what you're looking for?

http://www.candlepowerforums.com/vb/showthread.php?t=149804

 

[Black Rose]

I also intend to conduct a self-discharge test on these batteries.

I've done 3-month and 6-month self-discharge tests on them.

After 3-months the cells had 84% of their charge.
After 6-months, the cells had 80% of their charge.

 

[beamis]

Well, tonight I finished running a shoot out between two AA Eneloops and 2 AA Rayovac 4.0's. I charged each on the Maha C-401FS until the lights turned green, and then I removed them and started the discharge. The two Eneloops were in slots 1 and 2 on the Maha C9000, and the Rayovacs in slots 3 and 4. Every 5 minutes I took a reading for each battery and averaged between the two of each type. I was VERY surprised at the result. The Rayovacs hold their own against the Eneloop at 1000 mA. There is barely a difference between the two at this load.

I fully expected the Rayovacs to prove inferior to the Eneloops even at 1000 mA. Sometimes the data prove our intuition wrong. This does not mean that the Rayovacs are as sturdy or consistent as the Eneloops, but out of the box at least they perform well. I would cautiously say that they are at least worth the $1 per unit price I bought them for.

 

[beamis]

I suppose my next move will be to conduct this same test using a different set of batteries. Interesting indeed.

 

[beamis]

I've done 3-month and 6-month self-discharge tests on them.

After 3-months the cells had 84% of their charge.
After 6-months, the cells had 80% of their charge.

That's not too bad. After this testing I'm curious about the longevity of these cells. I almost feel like I've been insulted because a lowly Rayovac is running neck and neck with Eneloops (electrically speaking), so I want to find a fault. It looks like Eneloops are better on the LSD end, and I'm guessing they will prove to last through more charge cycles also, but without solid testing you never can tell.

 

[carbine15]

YOu guys all assume that the cheaper cells will run through fewer cycles or perform less admirably at a given load. Because of what? Marketing? Hype? Pricing? What if the cheaper cell is better (or as good) in every way. LOL wouldn't that be a hoot?

 

[beamis]

I think it would be great if it turned out that there were some "cheap" cells that competed with Eneloops in a meaningful way. It would mean that competition was strong in the battery business and everybody will benefit. I'm just very cautious in proclaiming that one cell is as good as an Eneloop based off of one test. Eneloops have been subjected to all sorts of tests on this and other sites, and it will take some strong and consistent test results for me to be comfortable declaring another cell on par with the Eneloop.

 

[snakebite]

just rebuilt a 2way pack with these 4.0's.
this radio gets used heavily and uses a fast charger that terminates on temp.
it also lacks low voltage shutdown so an occasional deep discharge will happen.
maha 777+2 test shows 1997 mah on the assembled pack after break in.
in a few months we will know.btw i last rebuilt it 4 years ago with the green sanyo "industrial" 1800's.
those had several hundred cycles on them and had lost enough capacity that the rig was dead in 1 day.it would run in recieve 2 days on these when new.
tx on high is around 1.5a on high on 12v.

 

[ltiu]

I'm going to Fry's and I'm buying some of these Rayovacs for my HOTWIRE!

 

[beamis]

Ok. So I repeated the experiment tonight with different batteries just to rule out some coincidence like getting a really good pair of Rayovacs and a bad pair of Eneloops. Here are the results:

It seems to me that at 1000 mA the Rayovac holds its own against the Eneloop. The best Eneloop cell and the worst Rayovac cell were only separated in capacity by 2%. Not bad for a sub-$1 battery.

 

[carbine15]

push it harder. Its only fun when something breaks.

 

[beamis]

I wish I could. The C9000 doesn't go any higher.

 

[beamis]

Here's a 500 mA test using the same batteries as used in the second 1000 mA test.

One interesting thing I noticed was that there was no slight advantage to the Eneloop at the "knee" as in the 1000 mA tests. In fact, for about an hour and a half the Rayovacs were slightly higher voltage than the Eneloops.

I do not have anything more sophisticated or able than the Maha C-9000, so my discharge testing is limited to 1000 mA. If someone wants to push these cells harder, it might prove interesting.

Anyone interested may access the data for these graphs here.

 

[Niconical]

I have 2 of the Maha C9000, and a multimeter, but how do you check the voltage without removing the battery?

The metal pointy bits (dont know what they're actually called) are thin, but certainly not thin enough to touch the + of the battery while it is still in the charger.

Any tips?

´

EDIT: I just thought, the C9000 displays the voltage for each cell as it discharges.
I didn't really pay attention to that before (just used breakin and charge), so is that what you use, read it from the display at the correct intervals?

 

[beamis]

Yes. When I want to use a multimeter to read the voltage, I just loop a paperclip around the positive button before inserting the battery. Then I can take the readings from the paperclip.