NiMh Battery Shoot Out

[Black Rose]

I bought a pair of Varta ready2use AA cells yesterday.

I wonder if these are the European version of the Rayovac Hybrid (Varta and Rayovac are Spectrum brand companies).

It's interesting that Varta also sells a 1600 mAh version of the AA cells.

One interesting thing is that the Varta cells say they retain 80% charge after 1 year. The ROV are 80% after 6 months.

 

[Raymond]

I've heard that before, that they're the same as the rayovac cells.

I plan to store them, together with a pair of panasonic infinium cells for a certain time and test how well they keep their charge.

I'm not sure about how long I want to store them. On the one hand, it's cool to find out how well they perform after six months. But on the other hand, personally, I find results after a month a lot more interesting.

 

[Mr Happy]

If you are able, close up photographs of each end of the cell would be interesting. We could see if they look the same as Rayovac Hybrids.

 

[Raymond]

 

[Black Rose]

I currently have 4 Eneloop AAA cells on a Break-In cycle on my C9000.

During the rest period following the discharge stage of the Break-In cycle, the following capacities were reported:

809, 809, 811, 809 mAh

Not bad for 800 mAh cells

 

[Black Rose]

I currently have 4 Eneloop AA cells on a Break-In cycle on my C9000.

During the rest period following the discharge stage of the Break-In cycle, the following capacities were reported:

2008, 1955, 1950, 1976 mAh

Cell #1 is the first AA Eneloop cell out of the 24 I've put through a break-in cycle to exceed the labeled capacity.

I've had 6 of the 8 AAA Eneloops I have exceed the labeled capacity during a break-in cycle.

Very interesting cells.

 

[TorchBoy]

Re: NiMH Battery Shoot Out

Cell #1 is the first AA Eneloop cell out of the 24 I've put through a break-in cycle to exceed the labeled capacity.

I've had a handful that have exceeded 2100 mAh, although that Break In was after a few usage cycles.

 

[1dash1]

I currently have 4 Eneloop AAA cells on a Break-In cycle on my C9000.

During the rest period following the discharge stage of the Break-In cycle, the following capacities were reported:

809, 809, 811, 809 mAh

Not bad for 800 mAh cells

My results were similar:

804 ... 809 ... 806 ... 809 mAH

And after two addtional cycles of charging/discharging @ 200 mA, the last discharge values were:

803 ... 810 ... 810 ... 812 mAH

Amazingly consistent. Speaks volumes for Sanyo's quality control.
(Says an a lot about the precision of the MAHA C9000, too.)
:twothumbs

 

[1dash1]

And here's the one month self-discharge test for my MAHA Powerex 2700 AA cells, discharged @ 500 mA:

2184 ... 2235 mAH
Average = 2210 mAH

They were charged a month ago on a MH-C401FS. So, I'm not sure exactly what the original charge was. But after the self-discharge test, I put the batteries through one cycle of charging/discharging @ 500 mA on the C9000 and here were the discharge values:

2615 ... 2625 mAH
Average = 2620 mAH

(Very good for batteries that I bought 18 months ago.)

Assuming the batteries were charged to the same level by the MH-C401FS, that would mean that the MAHA Powerex 2700 batteries retained 84% of their charge after 30 days.

I have two more originally charged batteries that I plan on holding onto for another 60 days, to do a comparative 90 day self-discharge test.
.
.

 

[TorchBoy]

Re: NiMH Battery Shoot Out

(Very good for batteries that I bought 18 months ago.)

How many cycles, do you think?

 

[Anders]

Hello 1dash1.

Thanks for the info about the 2700 cells, sounds good.

A small "standard" here @ CPF is when charging with C-9000 is to keep them on the charger additional two hours after ready for trickle charging if not charged in the "break in" mode.


Anders

 

[UnknownVT]

Next: Kodak Pre-Charged AA 2100 mAH (hybrid) batteries
Btty #1 ..... Btty #2 ..... Btty #3 ..... Btty #4
2003 .......... 2015 .......... 2016 .......... 1986 (mAH)
Btty #1 ..... Btty #2 ..... Btty #3 ..... Btty #4
1987 .......... 2000 .......... 2011 .......... 2005 (mAH) CYCLE No. 1
1992 .......... 2009 .......... 2013 .......... 2016 (mAH) CYCLE No. 2

Thank you VERY much for the Kodak Pre-Charged results

Just a point of curiosity - don't the results from last 2 - cycles 1 & 2 - almost seems as if the battery numbers/sequence had been rotated by one ie: # 4, 1, 2, 3?

Any ideas why battery #1 from cycles 1 & 2 seem much closer to battery #4 in the initial readings?

I've been very interested in the Kodak Pre-Charged and have done a hodge-podge of ad-hoc experiments comparing these to eneloops in eneloop vs. Kodak Pre-Charged Voltage Maintenance.

From this I can say that eneloops seem to hold/maintain a higher operating voltage under load by about 2-5%. But for most practical usage, eneloops and Kodak Pre-Charged seem to be about equal - probably because the total energy capacity (mW-hrs) is probably very similar - ie: the higher operating voltage of the eneloop compensates for the slightly higher current capacity of the KPC - giving equal/similar energy capacity.

 

[1dash1]

Re: NiMH Battery Shoot Out

How many cycles, do you think?

TorchBoy:

The Powerex 2700 batteries were never conditioned. Just stuck in the charger and go. Total number of cycles discharged during the last 18 months, definitely less than 20 cycles. I'd guess somewhere around 10-12 cycles.

 

[1dash1]

Thank you VERY much for the Kodak Pre-Charged results

Just a point of curiosity - don't the results from last 2 - cycles 1 & 2 - almost seems as if the battery numbers/sequence had been rotated by one ie: # 4, 1, 2, 3?

Any ideas why battery #1 from cycles 1 & 2 seem much closer to battery #4 in the initial readings?

I've been very interested in the Kodak Pre-Charged and have done a hodge-podge of ad-hoc experiments comparing these to eneloops in eneloop vs. Kodak Pre-Charged Voltage Maintenance.

From this I can say that eneloops seem to hold/maintain a higher operating voltage under load by about 2-5%. But for most practical usage, eneloops and Kodak Pre-Charged seem to be about equal - probably because the total energy capacity (mW-hrs) is probably very similar - ie: the higher operating voltage of the eneloop compensates for the slightly higher current capacity of the KPC - giving equal/similar energy capacity.

Unknown VT:

I don't know why the readings seem anomolous. All I can report is that the batteries were never removed from the C9000 unit, so there was no opportunity for them to get mixed up. And I double-checked the numbers to ensure no transposition errors.

And thanks for your additional work about the operating characteristics of the Eneloop vs. Kodak Pre-Charged!

 

[etc]

And here's the one month self-discharge test for my MAHA Powerex 2700 AA cells, discharged @ 500 mA:


Assuming the batteries were charged to the same level by the MH-C401FS, that would mean that the MAHA Powerex 2700 batteries retained 84% of their charge after 30 days.

I have two more originally charged batteries that I plan on holding onto for another 60 days, to do a comparative 90 day self-discharge test.
.
.

Thanks for the report, I use these cells all the time.

I wonder how many cycles total can you use them for until you have to discard them.

 

[1dash1]

I wonder how many cycles total can you use them for until you have to discard them.

Etc:

For my personal use, the batteries will probably become functionally obsolete before they are physically obsolete.

* * * * *

The test results (along with other anecdotal reports regarding the moderate discharge rate for the Powerex 2700 cells) has caused me to reconsider jumping onto the Low Self-discharge bandwagon.

• For low-use applications (replacing batteries only once or twice a year), alkalines are cost effective.
• For high-use applications, the Powerex 2700's better fit my needs.
• For everything in between, I need to either spend more time on recordkeeping or just use Eneloops.

I haven't quite figured out what to do about 14500's and 123's. My guess is that I'm rapidly approaching my threshhold for keeping this a fun (and safe!) activity. So, I'll focus most of my energy (pun intended :naughty on AA's and AAA's for now.

 

[servaas]

And here's the one month self-discharge test for my MAHA Powerex 2700 AA cells, discharged @ 500 mA:

2184 ... 2235 mAH
Average = 2210 mAH

They were charged a month ago on a MH-C401FS. So, I'm not sure exactly what the original charge was. But after the self-discharge test, I put the batteries through one cycle of charging/discharging @ 500 mA on the C9000 and here were the discharge values:

2615 ... 2625 mAH
Average = 2620 mAH

(Very good for batteries that I bought 18 months ago.)

Assuming the batteries were charged to the same level by the MH-C401FS, that would mean that the MAHA Powerex 2700 batteries retained 84% of their charge after 30 days.

I have two more originally charged batteries that I plan on holding onto for another 60 days, to do a comparative 90 day self-discharge test.
.
.

A similar test has also recently been conducted on new 2700mAh Powerex cells at http://wolfeyes.com.au/news/?p=9.

 

[SilverFox]

This thread is a bit big. I have started Part II here.

I am closing this thread and we can pick it up there.

I will continue to update the first post as I get new test data.

Tom