Powerex 2700mAH AA / 1000mAH AAA testing results

[wptski]

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?

 

[Anders]

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]

 

[RobbW]

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.

 

[RobbW]

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.

 

[balticvid]

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.

 

[hank]

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.

 

[geepondy]

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/

 

[BentHeadTX]

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.

 

[etc]

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.

 

[hotlips69]

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).

 

[hotlips69]

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?

 

[SilverFox]

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

 

[hotlips69]

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.

 

[SilverFox]

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

 

[hotlips69]

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!

 

[SilverFox]

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

 

[Newuser01]

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.

 

[coppertrail]

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

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.

 

[SilverFox]

Hello Chris,

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

Tom

 

[coppertrail]

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.