Queries on charging new Powerex 2700mAh Ni Mh AA batteries

[kirby]

[FONT='Arial', 'sans-serif']I just run the "break in" cycle on four new Powerex 2700mAh ni mh AA batteries. Took about two days to complete.[/FONT]



[FONT='Arial', 'sans-serif']I only got between 2500-2550 mAh according to the display on Maha C9000.[/FONT]



[FONT='Arial', 'sans-serif']Is that normal? Maybe it might take a few cycles before it climbs up to near 2700mAh?[/FONT]

[FONT='Arial', 'sans-serif']Should I start using the batteries now or should I select the "cycle" option on Maha C9000 and run the cells through a few cycles?[/FONT]

[FONT='Arial', 'sans-serif']Thanks.[/FONT]

 

[Mr Happy]

If you had run the break-in cycle on Eneloops, you would "only" have got 1900-2000 mAh. Are you unhappy with the extra 500 mAh?

 

[Black Rose]

I'm guessing he was expecting to see numbers in the mid 2600 mAh range for his 2700 mAh labeled cells instead of the 2500 mAh he got.

Some cells take a lot of work to get them going, others work well right away.

 

[Mr Happy]

Yes, I know. But I think 2700 is really pushing the limits on AA cell capacity, and we know that label capacities do tend to be a little optimistic, especially on the higher capacity cells.

It's also true that it often takes a few cycles to bring cells up to best performance. So after the break-in it wouldn't hurt to run a few charge/discharge cycles at higher currents and see if the numbers get better.

 

[kirby]

If you had run the break-in cycle on Eneloops, you would "only" have got 1900-2000 mAh. Are you unhappy with the extra 500 mAh?

They are nont Eneloops. They are Powerex 2700mAh non LSD batteries. Supposed to be one of the best brand along with the Sanyo which I shall do a 'break-in" next. http://thomasdistributing.com/shop/...html?SP_id=&osCsid=6t4o2c4vk72ffq27e7k96uf722

http://thomasdistributing.com/shop/...ml?SP_id=78&osCsid=6t4o2c4vk72ffq27e7k96uf722

Just received these recently.

 

[kirby]

Yes, I know. But I think 2700 is really pushing the limits on AA cell capacity, and we know that label capacities do tend to be a little optimistic, especially on the higher capacity cells.

I there are some reviews on CPF.
http://www.candlepowerforums.com/vb/showthread.php?t=136214

Here are other reviews
http://www.users.on.net/~mhains/Reviews.html
http://www.users.on.net/~mhains/Tables/swiff/Powerex2700Cell.swf
http://www.users.on.net/~mhains/Tables/swiff/Sanyo2700Cell.swf

http://www.digitaldingus.com/reviews/maha/maha2700mah/

From the above it seems like you can get fairly close or exceed 2700mAh for both Powerex and Sanyo.

 

[kirby]

It's also true that it often takes a few cycles to bring cells up to best performance. So after the break-in it wouldn't hurt to run a few charge/discharge cycles at higher currents and see if the numbers get better.

Is that better then actually using the batteries and then charge them up?

What charging and discharging rate would you suggest?
How many cycle?

Thanks.

 

[kirby]

Furher disappointment.

After using the four AA, I ran a refresh-analyse cycle. The capacity dropped further to well below 2500mAh, between 2450 and 2400.

Ran one of the four AA through three cycles on Maha C9000 and the reading was the same.

I thought Powerex is a good brand and supposed to have capacity close or fairly close to the rated capacity.

I shall try the Sanyo 2700mAh next.

 

[Black Rose]

Regarding the lower reported capacities, take a look at this thread, posts 75 to 79 for some info that might help.

I noticed that when I use the Refresh & Analzye cycle, that my cells (Eneloops in that particular case) reported lower numbers than the Break-In cycle.

 

[etc]

Used these cells for a while, they are the best non slow discharge cell to use IMO.

 

[Bones]

...
I thought Powerex is a good brand and supposed to have capacity close or fairly close to the rated capacity.
...

The Powerex 2700mAh do have a long standing reputation as one of the best high capacity cells kirby.

Comparative capacity measurements should always be based on the same criteria that was used to determine the cells initial capacity. This criterea has been determined by the International Electrotechnical Commission. It specifies a continuous charge for 16 hours at .1C, followed by a one hour rest period, then a continous discharge at .2C to 1.0 volts.

Capacity measurements based on any other criterea are always misleading to a greater or lessor degree. Generally, faster charges and discharges will result in lower capacity measurements. The break-in cycle of the MH-C9000 is generally considered adequate for a reasonable approximation of the IEC criteria.

As well, most cells list a typical and minimum capacity. I don't recall what it is for the Powerex 2700mAh, but for the Eneloop, the typical is 2000mAh and the minimum is 1900mAh. As long as a measurement based on the IEC criterea falls within this range, a cell is deemed to have met rated capacity.

 

[BentHeadTX]

I tested the Powerex 2700's almost two years ago on a Cadex 7200ER professional battery analyzer and they worked very well. I had the analyzer prime the batteries then cycle them a few times at 1000mA charge and 540mA discharge. They varied from about 2650 to 2720mAH.

The C9000 is a great analyzer but is set to never run the charge to the max that the batteries can take. This prevents missing negative delta V so the batteries won't be overcharged and destroyed.

My 2700's started to get very high self discharge rates after a year of use/abuse and I recycled them about 6 months ago. My Eneloops still kick butt after their first year of use so I use them exclusively in most of my lights.

 

[Albar]

I'm a little confused about my MH-C9000 battery charger and how to properly charge my new batteries. I did the Break-In cycle for 8 AA's and put them away for about a month.
A- Should I refresh. I have a lot of photo shooting to do this weekend with Super Bowl here.
B- What settings should I use for Refresh and Analyze?
I don't quite understand charge rate and discharge rates.
Thanks!
Albar
[email protected]

 

[SilverFox]

Hello Albar,

Welcome to CPF.

Just put them in the charger and top them off and they will be good to use.

Tom