# Powerex 2700mAH AA / 1000mAH AAA testing results



## BentHeadTX (Oct 8, 2006)

I have been testing Powerex 2700 mAH AA and Powerex 1000mAH AAA cells all week. Decided to do a forming charge at 200mA on the 2700's and a 80mA forming charge on the 1000's. First, what I used to test them.

Cadex 7400ER battery analyzer
LaCrosse BC900 battery analyzer
Maha MH-C401FS charger (AAA)
ZTS battery tester
Fluke 179 True RMS multi-meter

First the Powerex 2700mAH AA NiMH cells 

Forming charge of 200mA was performed by the LaCrosse BC900 battery analyzer Version 32 

Cadex 7400ER battery analyzer 
0.2C charge and 0.2C discharge rate (540mA) Two cycles
0.92V voltage cut-off 
97 to 99% on twelve batteries (2619mAH to 2673mAH) 

Loaded 8 of them in series for a 9.6V 2700mAH pack with 0.2C charge/discharge and 1.0V cut-off two cycles
94% (2538mAH) 

Tested at 1 amp charge 1.75 amp discharge 1.0V cut-off two cycles (four batteries tested) 
93 to 94% (2511mAH to 2538mAH) 

The reason for the odd 1.75 amp discharge rate is to see how they would perform when loaded down with my MillerMods U bin L1P helmet light. An hour twenty minutes of runtime rocks! :rock: 

Testing with BC900 battery analyzer 1000mA charge and 500mA discharge 0.9V cut-off

2.81 to 2.91 Ah with all twelve batteries tested. 


Powerex 1000mAH AAA cell testing (four cells)
Two cells formed on Cadex at 80mA charge and two cells formed at 200mA on a Maha MH 401FS

0.2C charge/discharge rate (200mA) two cycles
97 to 99% (970 to 990mAH) 

0.5C charge (500mA) 1.3C discharge (1.3 amps) 0.92V cut-off two cycles
91 to 93% (910 to 930mAH) 

Oddball rate due to testing for a Peak Baltic Super Ultra Power AAA Luxeon flashlight to determine runtime. 

0.5C charge (500mA) 1.0C discharge (1 amp) 1.0V discharge rate two batteries in series (2.4V) Two batteries that gave equal 92% rate at 1.3 amp discharge were chosen since they were balanced. 

93% (930mAH) 

Reason for testing in a series pair is to check estimated runtime for a Peak Baltic Super Ultra Power 2xAAA Luxeon flashlight. 

Overall, the Powerex 2700mAH AA cells have the highest capacity I've ever seen. :thumbsup: Very impressive that they hold up under the 1.75 amp discharge testing and do fine with 8 of them in series (upcoming Quad XR-E Mag) The BC900 testing was done after the 8 in series testing to see how far out of balance they became (2.84 to 2.91 Ah with the 8 cells) 

What really, really impressed me was the Powerex 1000mAH AAA cells. My guessimate was 750mAH at 1.3 amp discharge but they grunted out at least 910mAH. Having them hold 940mAH at a 1C discharge with two in series was icing on the cake.

Since I only had two Cadex channels available at the time, I went with testing how well the Maha MH 401FS forms them at C/5. The Maha formed batteries actually outperformed the Cadex formed batteries at C/13 The sample size was way to small but the rest of the guys at work saw my results and went with the Maha. 

There you go... my first major battery testing. Can't hold a candle to SilverFox but I figured somebody might find my results interesting.

EDIT: The Powerex 1000's were discharged at 1.3 amps (C1.3) and not 1.25 amps. Was recharging one of the cells and noticed the battery label stated 1.3 amps.

ADDED 21 October 
One of the guys at work took two of his Powerex 1000mA AAA batteries and connected them to the Cadex to try something different. He ran them at a 80mA charge/condition/200mA discharge rate for two cycles and after 56 hours (and still recharging) his results were 98% and 100% on one battery and 99% and 97% on the second battery. 

This is the long slow charge with termination at 1.53V the Cadex performs. I am not aware it will allow you to dumb charge the battery as I have check the many functions it performs in the last few months. 

Checked two of my AAA batteries in the BC-900 that were rated 97 and 99% on the Cadex. They returned 983mAH and 1039mAH with a 200mA charge (C/5) and 100mA discharge (C/10) rates. Although the BC-900 reads slightly high, it does point out which battery is the strongest so I can keep an eye on battery balance across packs. 

My co-workers results with four 1000mA Powerex cells on the Cadex 7400ER 80mA charge/recondition/200mA discharge are 97%, 99%, 99% and 100% so after 8 batteries tested, they all read 97 to 100% with about a 99% average across 8 cells.


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## wptski (Oct 8, 2006)

Thanks for the test! I use a Pro Former for forming my cells and packs. Wondering how the BC900 worked at 200ma which is less than .1C for a 2.7Ah cell? Did you time it for x amount of hours? It didn't terminate?

I'm glad that you did a mind refresh on the point that BC900 capacity test are several hundred millamps higher than most other means of testing!

I just ordered some PowerEx 1000mAh AAA the other day!  I need not test them now!!


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## BentHeadTX (Oct 8, 2006)

wptski said:


> Wondering how the BC900 worked at 200ma which is less than .1C for a 2.7Ah cell? Did you time it for x amount of hours? It didn't terminate?



My BC900 terminated at 1.41 VDC on each cell, it has never had any problems charging at such a low level (I got lucky!) However, it would charge for around 20 minutes at 0.2C when I hooked it up to the Cadex. The ZTS tester indicated a full charge after coming off the BC900 so I proclaimed it good enough. 

Yeah, I have noticed that the results tend to be about 5 to 6% higher than the Cadex when I get the cutoff at 0.92V (won't do 0.90V) Not bad considering the Cadex costs over 80 times what a BC900 does, not bad at all. The BC900 agrees with the Cadex when it comes to cells capacity relative to each other. I plan on getting another LaCrosse so I can condition 8 cells at once for my LuxV and Quad XR-E Mag mods. 

The Powerex 1000's are the most impressive batteries I have tested, I can beat on them at 1.3C and they handle it without a wimper. I figured Sanyo came out with 1000mAH cells that might be 900's in reality but I was proven wrong. Always nice to be wrong on occasion.


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## wptski (Oct 8, 2006)

BentHeadTX said:


> My BC900 terminated at 1.41 VDC on each cell, it has never had any problems charging at such a low level (I got lucky!) However, it would charge for around 20 minutes at 0.2C when I hooked it up to the Cadex. The ZTS tester indicated a full charge after coming off the BC900 so I proclaimed it good enough.
> 
> Yeah, I have noticed that the results tend to be about 5 to 6% higher than the Cadex when I get the cutoff at 0.92V (won't do 0.90V) Not bad considering the Cadex costs over 80 times what a BC900 does, not bad at all. The BC900 agrees with the Cadex when it comes to cells capacity relative to each other. I plan on getting another LaCrosse so I can condition 8 cells at once for my LuxV and Quad XR-E Mag mods.
> 
> The Powerex 1000's are the most impressive batteries I have tested, I can beat on them at 1.25C and they handle it without a wimper. I figured Sanyo came out with 1000mAH cells that might be 900's in reality but I was proven wrong. Always nice to be wrong on occasion.


At 200ma rate, the BC900 should take approx. 13.5 hrs. on 2.7Ah cells. How long did the BC900 take? The forming charge should be strickly timed and not governed by a charger's termination. That's why I got the Pro Former becasue it's made just for that.


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## BentHeadTX (Oct 8, 2006)

wptski said:


> At 200ma rate, the BC900 should take approx. 13.5 hrs. on 2.7Ah cells. How long did the BC900 take? The forming charge should be strickly timed and not governed by a charger's termination. That's why I got the Pro Former becasue it's made just for that.



The batteries were 60% charged when I received them in the mail. The BC900 showed it "put in" between 850mAH and 970mAH across the dozen cells I tested. It terminated with each cell at 1.41 volts but the ZTS stated they were all full. 

Then put them on the Cadex and noted it continued to charge them at 540mA (C/5) for about 20 minutes as the voltage rose to 1.53 VDC per cell. I set -DeltaV at 8mV on the charger to "catch" the voltage depression quicker. 

The 1000mAH AAA batteries were formed at 80mA and it took about 10 hours to terminate the charge at 1.53V. 

A special note with the Cadex 7400ER when it charges/discharges. If it don't hit 100% capacity (or capacity limits you set) it does a reconditioning thing were it slowly tapers off the discharge rate under 1.00V until it hits about 40mA and dumps the cell to 0.40 V. It then trickle charges at about 15mA to 1.11V and then tapers up to charge until it hits about 1.16V and hits it at full. Normally, this will increase the capacity 2% between the first discharge and the second discharge on new cells. There is some other mumbo-jumbo it does but I don't recall at this point. 

Another weird thing about the Cadex is it won't terminate with temperature. The 8 cells in series hit 45C and the analyzer went into "rest mode" and I watched the temps peak at 48C and then cool down to 35C before charging resumed. The two cycles and reconditioning took 22 hours with a C/5 rate (540mA charge/discharge) 

Those AA batteries are resting comfortable in their plastic cases after a long week of testing. The AAA cells are getting baked by my constant playing around with the new Baltic super ultra power (SUP) in 1xAAA and 2xAAA configurations. The light makes it about 50 to 55 minutes before the regulator kicks down to "battery saver mode" and gets dimmer over time. According to Peak, the SUP version pulls almost 1.5 watts from a single AAA and over 2 watts from 2AAA... glad I have the new 1000's! 

If I want to, I can tell the Cadex to charge at 20mA for days until it terminates... don't think I have the patience for that at this point.


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## jtr1962 (Oct 8, 2006)

BentHeadTX said:


> The batteries were 60% charged when I received them in the mail. The BC900 showed it "put in" between 850mAH and 970mAH across the dozen cells I tested. It terminated with each cell at 1.41 volts but the ZTS stated they were all full.
> 
> Then put them on the Cadex and noted it continued to charge them at 540mA (C/5) for about 20 minutes as the voltage rose to 1.53 VDC per cell. I set -DeltaV at 8mV on the charger to "catch" the voltage depression quicker.


When the BC-900 (or any other rapid charger) says the cells are full it then goes into a trickle charge. You can't rapid charge cells to 100%. I find that leaving cells on trickle in the BC-900 for about another 12 hours gives me about 5% more capacity. After 12 hours trickle I repeak the cells twice (just set the BC-900 to charge mode), letting them rest for at least 5 minutes after they're full. Usually the charger will only put about 100 mAh into the cells with each repeak. I then set it to test mode and let it do it's thing. This is the usual protocol I use when I test cells for capacity on the BC-900.

I think the BC-900, at least in the 1000 mA charge/500 mA discharge setting, may be giving optimistic results. I'm in the process of testing to confirm this. I have 8 Assia 3000 mAh cells which tested at either 2830 or 2840 following the procedure outlined in the first paragraph. I tested them on my test jig at 600 mA (C/5). The preliminary results were 2515 mAh (to 0.9V/cell). I'm in the process of testing them at 500 mA but this time I gave them a forming charge so as to hopefully maximize capacity. By midnight I should have the results.


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## BentHeadTX (Oct 8, 2006)

jtr1962 said:


> When the BC-900 (or any other rapid charger) says the cells are full it then goes into a trickle charge. You can't rapid charge cells to 100%. After 12 hours trickle I repeak the cells twice (just set the BC-900 to charge mode), letting them rest for at least 5 minutes after they're full. Usually the charger will only put about 100 mAh into the cells with each repeak.
> 
> I think the BC-900, at least in the 1000 mA charge/500 mA discharge setting, may be giving optimistic results.



Your statement about putting in another 100mAH on repeaking makes a lot of sense. The Cadex would charge at C/5 at 540mA for 20 minutes or longer AFTER the BC900 said they were full. Figure around 180mAH to 220mAH was added by the Cadex before it started the discharge routine. 

Looking forward to your results on the Assia to see if they are decent or just another overrated cell.


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## wptski (Oct 8, 2006)

BebtHeadTX:

Your use of the word "terminates" confuses me! Like in this quote "The 1000mAH AAA batteries were formed at 80mA and it took about 10 hours to terminate the charge at 1.53V." A true forming charge as I understand it is a constant current charge with no -DelataV, ZeroDeltaV or DT/Dt form of charging termination used. It charges till you stop it or a timer stops the charging.

Here's another one "If I want to, I can tell the Cadex to charge at 20mA for days until it terminates". This sounds like, you set a timer for so many days and it just stops, correct?


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## jtr1962 (Oct 8, 2006)

BentHeadTX said:


> Looking forward to your results on the Assia to see if they are decent or just another overrated cell.


The Assia are pretty solid. A few days ago I did a test at 2 amps and got 2433 mAh (to 0.9V/cell), 2483 mAh (to 0.8V/cell), and 2509 mAh (to 0.7V/cell). The Sanyos Silverfox tested only got a little more (2513 mAh) at 2 amps so the Assias are almost as good. Yes, the 3000 mAh is definitely an overrating, but the Assia cells could probably be honestly rated at 2600 or 2700. A lot of cell manufacturers these days push the rating system. I usually hear the ratings are supposed to be +-10%. Therefore if all your cells make 2700 mAh you technically _could_ rate them at 3000 mAh. The more honest cell manufacturers will rate their cells at the average they test at.


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## jtr1962 (Oct 8, 2006)

At 500 mA the latest results are 2505 mAh (to 0.9V/cell), 2521 mAh (to 0.8V/cell), and 2529 mAh (to 0.7V/cell). This is about the same as my aforementioned 600 mA results. This means the results on my BC-900 at 500 mA are about 13% high.


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## SilverFox (Oct 9, 2006)

Hello BentHeadTX,

Your test results look good to me...  

Tom


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## BentHeadTX (Oct 9, 2006)

wptski said:


> BebtHeadTX:
> 
> Your use of the word "terminates" confuses me! Like in this quote "The 1000mAH AAA batteries were formed at 80mA and it took about 10 hours to terminate the charge at 1.53V." A true forming charge as I understand it is a constant current charge with no -DelataV, ZeroDeltaV or DT/Dt form of charging termination used. It charges till you stop it or a timer stops the charging.
> 
> Here's another one "If I want to, I can tell the Cadex to charge at 20mA for days until it terminates". This sounds like, you set a timer for so many days and it just stops, correct?



wptski,
OK, I get it now... I thought forming charges were to charge the battery at or under C/10 until it terminated at full charge. Thanks for teaching me the correct terminology as what I was not doing was a forming charge. More of a low level charge with the Cadex reconditioning phase thrown in. All I know is after reconditioning, batteries perk up quite nicely wether the're new or older cells. 

Those Assia cells look very good for the price. I would get some but I have 12 2700's, 8 2500's, 4 2400's, 6 2300's, 4 2000's and 8 1700mAH AA NiMH cells in use. Forty-two AA cells to take care of and keeping conditioned is about my capacity at this point. Luckily I like 8AA Mag mods and 2AA EDC flashlights so they do get cycled quite often. 

A big thanks to SilverFox for testing all those batteries and charting them. It is quite the hassle to keep moving batteries around and keeping them all straight at different charge/discharge levels and such. All in the name of science (or being very anal)


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## wptski (Oct 9, 2006)

BentHeadTX said:


> wptski,
> OK, I get it now... I thought forming charges were to charge the battery at or under C/10 until it terminated at full charge. Thanks for teaching me the correct terminology as what I was not doing was a forming charge. More of a low level charge with the Cadex reconditioning phase thrown in. All I know is after reconditioning, batteries perk up quite nicely wether the're new or older cells.
> 
> Those Assia cells look very good for the price. I would get some but I have 12 2700's, 8 2500's, 4 2400's, 6 2300's, 4 2000's and 8 1700mAH AA NiMH cells in use. Forty-two AA cells to take care of and keeping conditioned is about my capacity at this point. Luckily I like 8AA Mag mods and 2AA EDC flashlights so they do get cycled quite often.
> ...


Several of the BC900 meltdowns were at 200ma with the newer high capacity cells. What seems like a good idea for the first charge really isn't since the unformed cells may miss termination, although nobody really knows forsure. William Cheuh from MAHA had a somewhat different take on why a lower charging rate may cause a BC900 to overheat. It was more of a design flaw rather then a cell capacity vs charging rate vs new cell problem.


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## SilverFox (Oct 9, 2006)

Hello Bill,

I think William has a better story than thinking the cause of the melt downs was do to a missed termination.

GP does tests where they charge a cell at 0.2C for an extended period of time. They claim that their cells can handle a 0.2C charge continually for a year. If you check a 2500 mAh cell, 200 mA is only 0.08C. That amounts only to a very aggressive trickle charge. At that charge rate, cells may warm up, but there is no way that they could get hot enough to melt down the charger.

If something malfunctions in the charger and it is charging at 1 amp with no termination, then you can generate enough heat to melt things down.

I find it interesting that we had a bunch of melt down reports, then nothing. Perhaps they changed something with the newer units.

Tom


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## wptski (Oct 9, 2006)

Tom:

Correct, Wiliam had a better theory about the meltdowns. Seems like it was a component design limit which could allow a current runaway condition.

I think that he said that MAHA has had their cells on low current charges for weeks also.

My BC900 melted at 700/350ma Test Mode on Duracell 2.3Ah cells that had about 5-6 cycles on them and not the first batch of four that I tested either! It was almost a year old to the day too.


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## LuxLuthor (Oct 9, 2006)

I have tried to promote the PowerEx brand ever since first hearing about them in the "Great Camera Battery Shootout" done a couple years ago. I knew they performed exceptionally better than 8-10 other batteries I had been using for various recorders, CD players, lights, mp3 players, toothbrush, etc. etc., but never had the equipment to prove it the way you did. 

Bravo!!!:rock:


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## hank (Oct 20, 2006)

Say more about this?
"The 1000mAH AAA batteries were formed at 80mA and it took about 10 hours to terminate the charge at 1.53V."

Is this done one battery at a time? I visited the site, looked for a FAQ but didn't find one.


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## wptski (Oct 20, 2006)

Forming is what's better done on the first charge at .1C or 1/10 of the rated capacity for approx. 16 hours using a constant current charge, meaning a dumb charger, no automatic cycling charger.

You can do them one at a time and it's probably better. I myself normally do four at a time this way.


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## BentHeadTX (Oct 21, 2006)

Added test results after testing four more Powerex AAA 1000mAH cells to the first post on the thread.


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## RobbW (Oct 21, 2006)

wptski said:


> Forming is what's better done on the first charge at .1C or 1/10 of the rated capacity for approx. 16 hours using a constant current charge, meaning a dumb charger, no automatic cycling charger.


 
Do I need special equipment to do this? I'm a newb, and have a Maha MH-402W on the way (with a bunch of the Sanyo 1000s and 27000s). Can I do this on the slow charge, or would I be looking at a different charger?

Thanks


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## wptski (Oct 21, 2006)

RobbW:

I use this Pro Former but you need a 12V power supply to operate it. Some high end RC chargers have a lower ma ranges which have no monitoring for which you have to time. Some use low amerage over-night chargers for this but I'm not familiar with them!

Maybe somebody else will reply listing their methods for a forming charge?


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## Anders (Oct 21, 2006)

Hello RobbW.

I use a dumb charger to make the forming charge to my cells.

In my case it charges with 270 mAh so if you buy a similar charger you have to charge your 2700 mAh cells 14-16 h. Dont forget to make them empty first.

Here:s how to calculate by Silverfox:
[font=&quot][/font][font=&quot]Battery manufacturers state that it takes 14 hours to charge a battery when the current is set to 0.1C. If there was no loss, it would only take 10 hours. This gives us a nice ratio to work with. Take your 2400 mAh cells and multiply them by 1.4 and you end up with 3360 mAh. If you are charging at 500 mA, you simple divide the 3360 by 500 and end up with 6.72 hours as the charge time. 

We all know that the capacities of these cells are exaggerated, so I took the 2400 mAh and figured you would be good to get 90% of that. Now we have 2400 times 0.90 which is 2160. Multiply 2160 times 1.4 and we have 3024. Divide 3024 by your charging rate of 500 and we end up with 6 hours and a little change.

Heat should not be an issue with this type of charge, as long as you shut the charger off at the end of 6 hours. If you wait for the charger to detect the peak, you may cook your cells while the charger continues to search for the end of charge signal. This is a problem with the first charge on a new cell, or on cells that have been in extended storage. Once the cells are "broken in," they tend to give a good end of charge signal that the charger can trigger off of and stop the charge.

Anders

[/font]


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## RobbW (Oct 21, 2006)

Anders said:


> Hello RobbW.
> 
> I use a dumb charger to make the forming charge to my cells.
> 
> In my case it charges with 270 mAh so if you buy a similar charger you have to charge your 2700 mAh cells 14-16 h. Dont forget to make them empty first.


 
Thanks for the information. I assume by "dumb charger" you mean a charger with low output and no charging "stages" to it?

How do I "empty" the cells? Just run them in a flashlight until they are dead? Completely dead?

Thanks for the formulas and thorough information. Much appreciated to this new user.


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## RobbW (Oct 21, 2006)

wptski said:


> RobbW:
> 
> I use this Pro Former but you need a 12V power supply to operate it. Some high end RC chargers have a lower ma ranges which have no monitoring for which you have to time. Some use low amerage over-night chargers for this but I'm not familiar with them!
> 
> Maybe somebody else will reply listing their methods for a forming charge?


 
Thanks for the link and info. I don't have a 12V power supply, but will look for an AC source or dumb charger. Whew! There's more to this than I imagined.


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## balticvid (Oct 22, 2006)

Wow. I just found this article on rechargeables.

I need help.

I have a MAHA MH-C401FS charger and eight AA Powerex 2300's. This was the highest rated batteries at the time.
I didn't use them because they didnt seem to work as well as regular lithuims.

What I didn't know is that I had to recycle them.
What are your recomendations as to how I can do this.
I also have a Calibeur DT830D meter. (Which sometimes is a mystery to me)

You can see I'm new to this.
Any suggestions would be appreciated.


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## hank (Nov 12, 2006)

By "recycle" do you mean deep discharge and recharge a few times, to be able to get them up to full capacity? 

If so -- either get a charger that will discharge and recharge (CCrane, newest Maha, many others) or run them down in a flashlight and recharge them at the low rate a few times. 

I rely on my Maha C401FS for slow full charge at home, and for travel and use the CCrane to test (one cell at a time) and charge up to 4 cells faster. 

But I am sure I'll eventually get the new Maha 9000 model.

I don't think you meant 'recycle as in "not throw in the trash"?
but if so -- any Radio Shack will take any kind of batteries, so will more and more hardware stores, and there will be more places. In California all batteries are now supposed to be collected to keep them out of the general landfill stream, as of Jan. 2006.


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## geepondy (Nov 12, 2006)

From a digital camera forum, I found a link where this guy says the Powerex's are the best 2700mah battery he's tested as well. Not sure if he's ever posted on cpf.

http://www.robertphotoblog.com/home/nimh-batteries/


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## BentHeadTX (Nov 12, 2006)

Finally figured out the name of the priming program on the Cadex (buried in the thick book) it's called extended prime so I ran the 8 PowerEx 2700's in series for a 9.6V pack. 

It trickle charged them at 50 to 54mA for 16 hours then finished charging to 1.53V termination at C/10 (270mA) It discharged at C/5 (540mA) and ran two more charge/discharge cycles at C/10 charge and C/5 discharge. 

The 8AA 9.6V pack returned 93%, 98% and 99% so the forming charge works well even with batteries that have been used. Another good reason to get the Maha MH-C9000 since it has a forming charge (called break in) of C/10 charge and C/5 discharge. 

Running your batteries down and recharging them seems to purk them up quite nicely.


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## etc (Nov 18, 2006)

I have these Powerex 2700 mAH AA cells. 

No scientific review from me, but they are nice. Behave well in magLite 2AA and 3AA, other lites and a digital camera.


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## hotlips69 (Jan 6, 2007)

Thanks for the excellent review of the Powerex 2700mAh batteries!

Please can someone confirm whether the MH-C204F charger (a few years old now) will FULLY & SAFELY CHARGE these latest Powerex 2700mAh AA batteries??

I don't really want to have to upgrade my old charger to the newer one unless my old one doesn't do the full charge (time to charge is not a factor).


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## hotlips69 (Jan 6, 2007)

hotlips69 said:


> Thanks for the excellent review of the Powerex 2700mAh batteries!
> 
> Please can someone confirm whether the MH-C204F charger (a few years old now) will FULLY & SAFELY CHARGE these latest Powerex 2700mAh AA batteries??
> 
> I don't really want to have to upgrade my old charger to the newer one unless my old one doesn't do the full charge (time to charge is not a factor).



Anyone?


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## SilverFox (Jan 6, 2007)

Hello Hotlips,

Welcome to CPF.

If the 204 charges in series, it should work fine. If it charges in parallel, and the cells are not equally matched, it will not do a good job. If it charges in parallel, and the cells are evenly matched, and you leave the cells on the charger for an extended period of time after the charge has completed, it should work.

Tom


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## hotlips69 (Jan 6, 2007)

Thanks Silverfox.

I've no idea how it charges, but I intend to just charge 2 (or maybe 4) of the exact same Powerex 2700mAh batteries at any one time.

I read on another forum that this charger MAY only be capable of charging up to 2200mAh hence my original question due to its (lack of) power.

The charger spec:- http://www.starbatteries.com/mahmhcharman.html

I'd appreciate if you could maybe have a quick look at the power specs and give me your thoughts.


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## SilverFox (Jan 6, 2007)

Hello Hotlips,

I am not sure how that charger charges, however it appears that the maximum charge time is 160 minutes. 160 minutes is roughly 2.7 hours. 2.7 hours X 500 mA = 1350 mAh.

If you do two charge cycles, you may be able to charge your 2700 mAh cells...

Tom


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## hotlips69 (Jan 6, 2007)

Silverfox, I'm really surprised!

Your comment & equation is logical, yet I've seen on some websites they advertise this charger with these batteries as a package!

Someone appears to be grossly incorrect and I don't think its you. :huh2:

In fact, this charger wouldn't even fully charge up my old 1800mAh batteries that I've been using with it for the past 3 years!


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## SilverFox (Jan 7, 2007)

Hello Hotlips,

Keep in mind that I am just going from the published information. It seems a bit low, but I don't have one of these chargers to check out.

Tom


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## Newuser01 (Jan 7, 2007)

hotlips69 said:


> In fact, this charger wouldn't even fully charge up my old 1800mAh batteries that I've been using with it for the past 3 years!


Okay, I don't mean any disrespect to OP or all of the experts here. But may be you may have some bad cells??

Juse a monkey in a box of wranches!

Regards.


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## coppertrail (Jan 7, 2007)

SilverFox said:


> Hello Hotlips,
> 
> Welcome to CPF.
> 
> ...


 It charges in parallel, just like the C204W. Rapid charge current is 500 mA. I'd be curious to see the results using a series charger.


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## SilverFox (Jan 7, 2007)

Hello Chris,

Do you happen to know if it really times out at 160 minutes?

Tom


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## coppertrail (Jan 7, 2007)

Hi Tom - 

I'm going off the specs sheet as well, and was responding to your questions that I quoted. I don't own this charger either.


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## SilverFox (Jan 7, 2007)

Hello Chris,

Thanks.

Tom


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## lyyyghtmaster (Feb 5, 2007)

I hope this reply isn't too late to be of any use!

Regarding the Maha MH-C204F charger, I am currently using three of this model. There are two independent charging circuits of two batteries each. The back of the charger states, "charger output: DC2.4V, 500 mA x 2Ch", which seems to imply series charging is used. Also, when you insert batteries, it won't start a pair charging until they're both in place. If the charger used parallel charging, this would require a sensor to determine if both bays of a pair had a load attached. That would be an added expense. Also, without such a sensor, Maha could have advertised it as a dual-rate charger, depending on whether the user inserted one or two batteries. These facts all point to it using series charging for each pair. 

The instruction sheet also says, "Charge time: 60-160 minutes*" and "Charge time will vary depending upon the brand, capacity, and condition of batteries being charged." I frequently charge Duracell 2650 mAh cells, and they charge fully, as compared to LaCrosse BC-900. It takes quite a bit more than 160 minutes when they're nearly dead. I guess the instruction sheet was written quite a while ago!

In use, I've never had any problems charging even casually matched pairs. I don't benchmark most of my cells, but I have never had any overheat. I always charge pairs that were used together, in series, in the same device. The use has to have been fairly recent, so that they could not have drifted too far apart from each other by self-discharge differences. If I can't assure these conditions, I use the LaCrosse or the MH-401FS, which have individual channels for each cell.

Hope this helps!

Mike


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## sajmmiller (Feb 5, 2007)

I have a Maha C204F which has functioned as my primary charger until recently receiving the Maha C9000. The C204F charges my Kodak 2500mAh NiMH in about 5 hours and terminates reliably. I only wish my C9000 charged as gently and terminated as reliably as the C204F. I don't think you will have any problems charging or discharging 2700mAh AA or 1000mAh AAA batteries in the C204F.

Scott


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