Powerex 2700's - very disappointed

[Closet_Flashaholic]

So,
I have been using 8 Powerex 2700 batteries over a period of about a year. They were never abused and required charging 1/month. So after about 12 cycles, I noticed the devices they were powering weren't running as long.

Sure enough after running a capacity test, all eight batteries are down to 2200 maH +/- 100 mA.. Unreal. I ran a few cycles on them on my C9000 and no difference. They are down 20% capacity from when I 1st got them after only 12 charge/discharge cycles. I might as well have just purchased some more eneloops. They are holding up well.

Never again. I have not seen any AA NiMH batteries rated over 2200 mAH work for any length of time. I will stick with eneloops and just replace more often I guess and the rest of the NimH manufacturers can go pound salt.

 

[monkeyboy]

Have you tried putting them through a few charge discharge cycles before measuring the capacity? This maybe all that is required.
EDIT: OK I just read your post properly

If not, try Ansmann AA's. These hold up very well in my experience. I've owned a set of 2700's for over 2 years. (I haven't tested them but they seem OK)

 

[Mr Happy]

I ran a few cycles on them on my C9000 and no difference.

Out of curiosity, did you try a break-in cycle?

Are all of them degraded equally, or are some worse than others?

I won't argue with your choice of eneloops though. They are a very well designed and high quality battery.

 

[Anders]

Hello Closet_Flashaholic.

Did you charge the cells with the C-9000 from day 1?
Did you take a voltage reading of them when "new"?

I have always thought that they where good, maybe you got cells from the first batch, it was a couple of years ago when they came out..

Anders

 

[Closet_Flashaholic]

Hello Closet_Flashaholic.

Did you charge the cells with the C-9000 from day 1?
Did you take a voltage reading of them when "new"?

Anders

Yes, I have used only the C9000 on them since day 1.

I did not take a voltage reading on them when they were new, however I did a 3 cycle break-in on them .2C/1C and they all ran about their rated capacity - 2700 mAH or close enough.

These types of cells had been out for a while before I had purchased them I never purchase anything that hasn't been on the market for a while. I learned my lesson with camera and computer equipment .

I have a good relationship with the supplier that I purchased these from. I will call them on Monday and see if they can do anything for me. However, they won't be obligated to since I am sure any manufacturer warranty has expired. If they do something, it won't be to purchase any more of these. Perhaps I will give the Ansman a try, however, I need to investigate them. Ansman doesn't seem to be a mainstream manufacturer so if they are a rebrand of another manufacturer, I'd like to make sure that they are not the same as Powerex...

 

[Anders]

Thankyou for your answer Closet_Flashaholic.

Hmm they have a very good reputation here....

Anders

 

[325addict]

did you ever try the Varta Professional 5706 2700mAh? I think these are really good, with my simple current-source style charger I reached over 2500mAh -the very first time I charged it!
Now, more than a year and several cycles later, they still perform flawlessly. My good old Walkman DC2 still runs forever on two of them :thumbsup:

Timmo.

 

[etc]

Mine Powerex cells worked OK for about 1.5 years...then suddenly all kinds of failures. Blowing up its size when charging, failure to terminate charge, do not power up some devices... some of them do not power up in cold weather but others do... I know I charged them way more than 12 times.

 

[BentHeadTX]

All my Powerex 2700's went to crap within 12 to 18 months, I had 12 of them.
Replaced all of them with Eneloops and have ordered 12 more Eneloops after they made it to 18 months at 95% + capacity on my C9000. Had a ton of Powerex 2500's and Energizers tank after a year also.
Eneloop only spoken here

 

[coppertrail]

Powerex guarantees their cells, might be worth an email to their customer service/support dept.

 

[mikevelarde]

sorry for a little off-topic here!!
I recently purchase 18 of those high capacity powerex D cell at a whooping 11,000 mah. out of the package the cell measure at 0.6V to 0.75V. after doing a conditioning cycle on the 808M which lasted for more than five days for the eight cell still discharging at 1 bar. I pull the plug and use the C-9000 instead.(with the help of some dowel)

After doing 2 break-in cycle on each of the cell using the C-9000. the available capacity is as follow is descending order:

1.9970 mah
2.9954 mah
3.9897 mah
4.9800 mah
5.9612 mah
6.9573 mah
7.9452 mah
8.9443 mah
9.9364 mah
10.9313 mah
11.9308 mah
12.9282 mah
13.9018 mah
14.8882 mah
15.8542 mah
16.8236 mah
17.8186 mah
18.7987 mah

The above discharge capacity is taken after all the cell are given 2 time break-in. although their break in capacity all register around 10ah+ hot off the C-9000. their discharge capacity using a discharge rate of 1,000 ma is taken after 4 hour rest from their completion of 2 times break-in cycle

The capacity printed on each D-cell is 11,000 mah. my experience of those cell is below my expectation!:thumbsdow

I wonder how they get those 11,000 and at what discharge rate?400ma?500ma?:thinking:

My observation is that the cell is manufacture for quite some time, their freshly open voltage drop to 0.6 to 0.75 per cell.

My conclusion is Maha = great charger and Maha NOT = great battery!!!

Will I be getting better capacity if I do a couple of cycle on them?:thinking:

and they don't reply to my email at all!!

 

[Mr Happy]

[deleted: comprehension failure]

Incidentally when you receive a new NiMH cell it should read above 1.2 V open circuit. If it reads anything as low as 0.7 V then in my opinion it is defective and should be returned.

 

[Bones]

I don't understand those numbers:

one point nine nine seven zero mAh
...

I believe the numbers before the point represent a numerical designation for each of the eighteen cells purchased by mikevelarde.

 

[mikevelarde]

Thanks a lot Mr. Bones for the clarification!!:twothumbs

 

[Mr Happy]

I believe the numbers before the point represent a numerical designation for each of the eighteen cells purchased by mikevelarde.

OK, that makes sense now. I must be slow today...

 

[Anders]

Hello mikevelarde.

As Mr Mappy says.

If the open voltage is so low, your cells must have been on the shelf like two years, the expected life for a nimh cell is 2-3 years so they where defective when you bought them.

I bought 6 Maha C cells in 2008, they also were low, but I think all of them were over 0,7 Volt. I got advertised mAh from them after a couple of cykles.

The customers must demand a date code on the cells if we want to buy fresh ones, we pay for good stuff, not old and bad.

Anders

 

[ampdude]

I haven't been impressed with the Powerex 2700's either. They don't power my digital camera as well as the old Sony and Energizer 2500's I had.

The Imedion LSD cells were total garbage for that same use and I had to return them.

That was quite awhile ago though, maybe things have changed.

 

[mikevelarde]

Thanks a lot Anders for your tip.

I lived outside of US of A. and the business practice here sometime does not permit outright return of certain merchandise. They did permit exchange of same item. (But I don't want to go over those crappy D cell again):hairpull:

By the way, they is no date code on those Powerex D cell.(don't see them on the package as well as on the cell body)

mikevelarde