# Duracell 2650mAh NiMH, test result



## Handlobraesing (May 23, 2006)

old stuff:



> Tested:
> Four Duracell 2650mAh AA rechargeable batteries. Available at Wal-Mart
> 
> Charge method: 0.36A x 9 hours on a dumb, timer controlled charger.
> ...



Update 7/21/06:

I tested the capacity with four cells in series. Since I don't know the accuracy of calibration of the BC-900, it wouldn't hurt to do it a different way anyhow.

4 cells connected in series Cells were fully charged and allowed to rest for about an hour.

~600mA discharge current. 






*the watt-hour capacity is of ALL FOUR cells combined. 
*measurement uncertainties= thermal coefficient of resistor and 0.025%+1mV voltmeter error. 


Great batteries, ghetto testing device.


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## InfidelCastro (May 23, 2006)

Excellent report, thank you. I was considering ordering some Sanyo 2700's, but if I can buy them at a retail store instead, I'll probably hold off for awhile until we find out for sure. My Energizer 2500's should tide me over until then.

The numbers you came up with are actually better than the Sanyo 2700's charted at in the NimH shootout, in the forum sticky above.


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## Handlobraesing (May 23, 2006)

InfidelCastro said:


> Excellent report, thank you. I was considering ordering some Sanyo 2700's, but if I can buy them at a retail store instead, I'll probably hold off for awhile until we find out for sure. My Energizer 2500's should tide me over until then.
> 
> The numbers you came up with are actually better than the Sanyo 2700's charted at in the NimH shootout, in the forum sticky above.



The difference is probably due to a different charge algorithm. Dumb charging does not suffer premature termination and even though it might not offer the best cycle life, it offers the most consistent, full charging.

I think SilverFox uses smart charging, but I prefer to use dumb charging for repeatability sake.


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## john2551 (Jul 20, 2006)

I got these today at Walmart, $15.87 for a pack of 8. That's less than $2 each!


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## wptski (Jul 21, 2006)

Handlobraesing said:


> The difference is probably due to a different charge algorithm. Dumb charging does not suffer premature termination and even though it might not offer the best cycle life, it offers the most consistent, full charging.
> 
> I think SilverFox uses smart charging, but I prefer to use dumb charging for repeatability sake.


Sure, a timed will result in more full charge. You can read that in the specs provided by some manufactures but is that what your going to use "all" the time? Most often, a smart charger is used and that's why SilverFox used one! A real life test.


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## Long John (Jul 21, 2006)

These Duracell 2650 mAh are not the same like the Sanyos 2700 mAh.

I have 20 pieces of the Sanyos and tested them several times. About 10 of them will have a capacity, more than 2,8 Ah, the other 10 more than 2,9 Ah.

Best regards

____
Tom


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## wptski (Jul 21, 2006)

Long John said:


> These Duracell 2650 mAh are not the same like the Sanyos 2700 mAh.
> 
> I have 20 pieces of the Sanyos and tested them several times. About 10 of them will have a capacity, more than 2,8 Ah, the other 10 more than 2,9 Ah.
> 
> ...


Tom:

How did you charge you charge/discharge those cells?


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## Long John (Jul 21, 2006)

Hello Bill

With the LaCrosse in test modus.

Best regards

____
Tom


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## wptski (Jul 21, 2006)

Long John said:


> Hello Bill
> 
> With the LaCrosse in test modus.
> 
> ...


Does Silverfox's Ni-MH ShootOut include the Sanyo 2.7Ah cells? Because the BC900 is know to produce capacities a bit higher(200mAh) than other means. The low voltage cutoff is being questioned in other threads also. I'm going to have to graph my v33 unit to see where the LVC is. Maybe we ought to start a BC900 accuracy thread!


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## Handlobraesing (Jul 21, 2006)

I don't know the accuracy of calibration on the CBAII or the BC900, so I tried a new method, see first post.


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## Ikonomi (Jul 21, 2006)

Well, that's all well and good, but I can't find them at Wal-Mart. 

I will try another. I wish Target carried these, but the only Duracells I can find around here (at Target or Wally World) are the 2500s.


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## wptski (Jul 21, 2006)

Handlobraesing said:


> I don't know the accuracy of calibration on the CBAII or the BC900, so I tried a new method, see first post.


Sooner or later, you'll run into a problem using those spring type clamps. The Schulze manuals list them in "what not to do".

I've used them to but a while I was using some 4xAA holders, unlike yours, these were two back to back. I was cycling some new cells that were over 2Ah, I don't remember the exact capacity. I was getting good capacity and all of a sudden, I get a 1600mAh. I have a clamp type holder setup for 4/8 AA cells. I used that and every cycle produced about the same capacity. I've marked those holders since then so if I ever run into that again, I'll weed the bad one out.

Get yourself up a good clamp setup. Lots use the Plastic ratcheting wood clamps and that's what I used too. Finding coppet sheet for the contacts was my problem. I ended up buying a small piece of copper gutter. Use double-face tape to keep it put. Soldering a large piece of copper can be fun.


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## ps56k (Aug 24, 2006)

Can I use my Maha C204F to charge these higher capacity NiMh batteries ?
I think I got it (actually 2) back when the NiMh batteries were 1600, etc


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## wptski (Aug 24, 2006)

ps56k said:


> Can I use my Maha C204F to charge these higher capacity NiMh batteries ?
> I think I got it (actually 2) back when the NiMh batteries were 1600, etc


Why not? Use the the fast charge mode or it'll take a long time.


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## Anders (Aug 24, 2006)

ps56k: "and will recharge even the higher capacity batteries of the future"

http://www.thomas-distributing.com/maha-mh-c204f.htm

But, it is always best to charge each battery independently.

Anders


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## Bullzeyebill (Aug 26, 2006)

Anders, why is it best to charge each cell independately. If I was using multiple batteries for an application, I think that charging them in parallel would be best to balance the "pack of batteries". All of the individual cells should be charged to the same voltage and amperage.

Bill


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## Anders (Aug 26, 2006)

Hello Bullzeyebill!

I think its best if you have cells started out at different states of charge or if you have cells that is defect.

The cell who is working properly or is almost full then will be overcharged and therefore take damage.

If you want to charge 1 or 3 cells you have problems.

Anders


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## SilverFox (Aug 26, 2006)

Hello Bill,

It is not recommended to charge NiMh cells in parallel. It is recommended to charge NiMh cells individually or in series.

You can get away with parallel charging if you charge at low currents and follow the charge with an extended trickle charge, or if you use cells matched on capacity. The balancing occurs during the trickle charge phase.

When charging NiMh cells in parallel, the least drained cell will peak first. Once it peaks, the temperature will rise in the cell, causing the voltage of the cell to drop. The charger continues to charge and the cell continues to heat up.

Adding thermal cut off to monitor each cell helps, but it can be difficult to get good thermal coupling with the cells. On top of that, thermal cut offs are usually adjusted for laboratory conditions and can have difficulties in "outside" conditions.

If you have a light that runs on one AA cell, you can do this experiment. Run the light on one cell until it is dead and note the run time. Take the dead battery and connect it in parallel to a freshly charged cell and leave it for several hours or overnight. Then take the dead cell that you would think to be "equalized" by the fresh cell and put it back into the light and note the run time again. You can then take the fresh cell that was supposed to "charge" the dead cell and compare the run time you get with it to the dead cell that was supposed to be "balanced" by hooking it up in parallel to the fully charged cell.

Let us know what you find out...

Tom


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## Bullzeyebill (Aug 26, 2006)

Whoops, I meant to say series. Must have been late when I posted.

Bill


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## twentysixtwo (Sep 23, 2006)

I'll be looking for these on my next trip to wally mart, I have a pile of Energizer 2300 MaH "made in China" which test on the Lacrosse to an average of 1979 MaH. Pretty sad.


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## Handlobraesing (Oct 30, 2006)

well not such a great update... The Duracell 2650mAh is among the fattest AA cells, pushing very close to the 14.5mm diamater limit. 

The wrapper is apparently thin to meet the size specs. The larger size doesn't get along with some battery holders. Add the two together, the batteries suffered chafe damage. 

So far I've got two damaged wrappers and they might be bound for the recycling bin soon before it shorts out


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## koala (Oct 30, 2006)

Buy some nail polish/varnish and paint it over. This kind of damage happens too often. I hate it.


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## WildChild (Oct 30, 2006)

I've had some rechargeables on which the wrapper was damaged. What I did is to put a drop of epoxy glue to cover the metallic part so it won't short. By the way, is it possible to know in what you damaged the cells? Here, I can enter the fat cells everywhere except in a remote control. I put in it some old 1800 mAh cells and they are tight fit.


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## wptski (Oct 30, 2006)

Yeah, since these new high capacity are a bit longer too, inserting/removing them is harder, so nicking the wrapper is easier to do!


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## WildChild (Oct 30, 2006)

UPDATE: The Duracell 2650 fits really well in my remote control. They are not tight at all.


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## Handlobraesing (Dec 4, 2006)

Update:
Six months later and some ~40 cycles later, two out of four 2.65Ah I have set aside for testing have lost 20% of capacity. 

They all tested at 2.6A+ when they were bought. Now two tests fine, but now two are down to 2.2Ah. 

Charging is usually done on a Duracell 30 minute charger or 15 minute charger.


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## wptski (Dec 4, 2006)

I wonder how many, what capacity, what brand over 2Ah is worth the trouble these days??


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## WildChild (Dec 4, 2006)

So cycle life of these cells is really low! But I consider that with 40 cycles, it still worth the money compared to alkaline! I've read somewhere that with RC, many people consider 10 cycles to be good and change their packs after that! I'm in the process in trying some Eneloop for normal usage! Their self-discharge rate seems much better than Duracell 2650 mAh (which I was finding nice). If their cycle life is high since they are only 2000 mAh I guess I'll always stick with them! I just hope Sanyo won't kill this product by trying to push with more and more capacity!


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## wptski (Dec 4, 2006)

WildChild said:


> So cycle life of these cells is really low! But I consider that with 40 cycles, it still worth the money compared to alkaline! I've read somewhere that with RC, many people consider 10 cycles to be good and change their packs after that! I'm in the process in trying some Eneloop for normal usage! Their self-discharge rate seems much better than Duracell 2650 mAh (which I was finding nice). If their cycle life is high since they are only 2000 mAh I guess I'll always stick with them! I just hope Sanyo won't kill this product by trying to push with more and more capacity!


I'd like to see where you read that ten cycles on the RC pack is considered good. A single cell's lifespan shouldn't be that much different than a pack or at least not that drastic.


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## WildChild (Dec 4, 2006)

http://candlepowerforums.com/vb/showpost.php?p=1549608&postcount=3

After some searching I found again the information!  This info is from SilverFox.


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## bob_ninja (Dec 4, 2006)

RC packs are different because they are generally stressed a lot (huge power draw). Moreover, in larger packs single bad cell will kill entire pack. Hence the higher failure rate. As opposed to a single cell used in a MP3 player or wireless mouse - low stress, small packs (1-2). It is easier to isolate the bad one and continue using others.


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## Handlobraesing (Dec 8, 2006)

bob_ninja said:


> RC packs are different because they are generally stressed a lot (huge power draw). Moreover, in larger packs single bad cell will kill entire pack. Hence the higher failure rate. As opposed to a single cell used in a MP3 player or wireless mouse - low stress, small packs (1-2). It is easier to isolate the bad one and continue using others.



Definition of useful life is quite different. Sustained battery voltage in direct drive (that is, controller is not limiting power going to motor) conditions pretty much determines how much power is delivered to the motor. I wouldn't be surprised if the sustained voltage under 30A load is diminished after ten or so uses. 

The batteries would still work fine, but it won't have the edge over other guys you're racing and cost you time on the track. If you were to take RC packs that's been written off as done deal and test it on a battery tester at C/5 rate (0.6A rate) it might as well have a very decent capacity.


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## s0lar (Jun 9, 2010)

I jus bought myself a Memorex Pro 1 Geniux (rebranded MAHA 9000) and discharged a Duracell 2650, among a lot of others. The cell was charged about 3 weeks ago on a 0.3C charger. 0.7A discharge gave me the wonderfull result of 2186mA! I like this cell. Too bad my 7 others are used for my electronics project and that is now property of my school.


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## TakeTheActive (Jun 10, 2010)

*Memorex Pro 1 Geniux = 'Rebranded' Maha MH-C9000?*



s0lar said:


> I jus bought myself a *Memorex Pro 1 Geniux (rebranded MAHA 9000)*...


This is the FIRST I've heard about a *'rebranded' Maha MH-C9000* - 

*Memorex Pro 1 Geniux*​


> > "The PRO 1 GENIUX is a product born from a close collaboration
> > tussen MEMOREX en MAHA POWEREX uit Taiwan, gespecialiseerd in het between Memorex and MAHA Powerex in Taiwan, specializing in
> > ontwerpen van hoogtechnologische laders. designing high-loaders. U kan via internet heel wat informatie You can be a lot of information over the Internet
> > inwinnen over de lader MH-C9000 met identieke eigenschappen ." ascertain the Charger MH-C9000 with identical properties. "
> ...


*Reference: ** Batterijlader Memorex "PRO 1 Geniux" = Maha MH-C9000? {JAN 2009}*

Memorex in the USA is NOT a brand I think of when I look for QUALITY... :thinking:


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## 45/70 (Jun 10, 2010)

TakeTheActive said:


> Memorex in the USA is NOT a brand I think of when I look for QUALITY... :thinking:



That's OK, Take. Aside from the fact that this thread is 4 years old, it's about Duracell 2650 NiMH cells anyway. 



s0lar said:


> ......The cell was charged about 3 weeks ago on a 0.3C charger. 0.7A discharge gave me the wonderfull result of 2186mA!......



That's actually pretty good, considering. Provided that high cap NiMH cells are either new, or used exclusively under low current load conditions, some of them hold up pretty well.

Dave


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## s0lar (Jun 11, 2010)

I have done a refresh and analyze at 
1.4A/0.7A and the result was 2420mA. The cell has had 3 cycles. I will do further testing, I really wish I ordered more. First I thought I would only need 4, so I ordered 8, but it seemed better to use 7 for my project in the end.
I might be able to reach 2500mA with this cell.


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