How long should AA rechargables last?

I have a digital camera that I use rechargable batteries in. I didn't get the rechargables to last for longer than a year. What I mean by that is that the batteries just don't hold a charge for nearly as long as they used to when I use them in the camera.

I am using a Maha charger and condition the batteries every time I charge them. The batteries I used were Powerex and Ansmann. I got it all through Thomas Distributing.

I just bought some Energizers and they hold a charge much better. But they are new.

Is this normal for rechargable batteries to die that fast?


Thanks.

ColtRifle said:

I am using a Maha charger and condition the batteries every time I charge them. The batteries I used were Powerex and Ansmann. I got it all through Thomas Distributing.

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Are you using NiCd or NiMH? You should take care of each slightly differently. I'm not sure conditioning them every time you charge is a good thing, for example.

This is an excellent resource for more info:
http://www.batteryuniversity.com/

Hello ColtRifle,

Welcome to CPF.

Battery life is often measured in the number of charge/discharge cycles they can endure before dropping to around 80% of their initial capacity. NiMh cells below 2000 mAh are generally good for around 500-1000 cycles. NiMh cells above 2100 mAh are generally good for around 100-300 cycles.

Keep in mind that heat kills NiMh cells, as does continual trickle charging. Some of the Maha chargers can get the cells quite hot during a fast charge. Heat can also be a problem if you happen to leave your camera on the dash in the hot sun, or find yourself constantly in a hot climate.

I have not seen any data on voltage retention during cycle testing. The battery manufacturers seem to concentrate on only capacity. I have found that the voltage under load will start to drop in as little as 50 cycles. It could be that your camera is seeing the voltage drop and signaling that the batteries are dead.

The RC people seem to push things to the limits. Some of them consider 10 cycles as a good life for critical use, and will go on to use a pack for a total of 20-50 cycles during practice.

I should also point out that a bad batch of batteries will make it out from time to time. Energizer is having problems with their 2500 mAh cells that were purchased around 8 months ago. A friend of mine purchased 16 of the Energizer 2500 cells, and has had to return 12 of them because they would self discharge in a matter of days.

You may have a bad cell. You need to charge your cells and measure the voltage when they come off the charger. Set them aside for a week and measure the voltage again. They should all be similar. If you end up with one cell that is off, it is probably the bad cell.

Tom

I too have energizer 2500s bought in 2005 date code september 04. they are lightly used,charged in a maha 204f.The 4 batteries take twelve hours to charge,only charge to 40or60%and then dont hold the charge for more than 10 days [not being used].they were bought from Thomas.Can i bring them back to life or return them and to who?

Hello Bp044,

Contact Energizer. They should send you a pre-paid to have you send the cells back to them and a cupon for new cells.

Tom

thank you silver fox for your Qick responce.

A camera will damage NiMH cells through over discharge if you aren't careful. What's the voltage of the cells when the "smart" charger says they are fully charged?

You shouldn't have to fully discharge the cells every time you charge them, if the cells are healthy.

If the cells aren't damaged through over discharge, and you use a good charger, they should last for many years. I have cells 5 years old that are in good shape. On the other hand, I ruined some in my camera by ignoring the low battery warning.

The charger that I have allows me to completely discharge the cells by pushing a button. It discharges them and then recharges them. Takes about 12 hours or so.

So I shouldn't completely discharge the batteries regularly?

Do I need to do it at all?

Thanks for all the responses.

ColtRifle said:

The charger that I have allows me to completely discharge the cells by pushing a button. It discharges them and then recharges them. Takes about 12 hours or so.

So I shouldn't completely discharge the batteries regularly?

Do I need to do it at all?

Thanks for all the responses.

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If your using an older MAHA charger, it probably conditions/charges two at a time and anytime that's done, they aren't going to be discharged/charged to the same state either!

They may just be unbalanced. If that's the problem only a charger that discharges/charges each cell by itself or seperate circuits will cure the problem.

Now the odd thing (to me) is that I have several older sets of cells (pushing 4 years) and I only now have had to replace two of the sets. I honestly didn't treat them all that well but they held up like troopers.

Now you are all making me nervous about my brand new energizers I bought to replace them (ugh).

zespectre said:

Now the odd thing (to me) is that I have several older sets of cells (pushing 4 years) and I only now have had to replace two of the sets. I honestly didn't treat them all that well but they held up like troopers.

Now you are all making me nervous about my brand new energizers I bought to replace them (ugh).

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Can say for sure but if they are four years old, what capacity are they? It may be more of a problem with the newer high capacity cells.

Re-read my post.. I mistyped a bit. What I was trying to say is that I have several older sets-of-four batteries. On one set I had two cells go bad, on another set I had one cell go bad. So I bought two new sets-of-four to keep things matched and I'm using the others (set-of-three and set-of-two) for miscl applications and they are still chugging along.

I can say for sure how old my sets are because I label all my sets of rechargables with date of purchase and a set # so I can keep them together. Beyond that though I just charge 'em and use 'em.

The cells I had to replace were 1650 mAh Maxell brand AA batts.
(woah, I went back and looked and my oldest set that is still working fine are 4 of the 1400 mAh Maxells that I use in an old "toycam").

zespectre said:

I can say for sure because I label all my sets of rechargables with date of purchase and a set # so I can keep them together. Beyond that though I just charge 'em and use 'em.

The cells I had to replace were 1650 mAh Maxell brand AA batts.
(woah, I went back and looked and my oldest set that is still working fine are 4 of the 1400 mAh that I use in an old "toycam").

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We'll see several years down the road how many of these high capacity cells are still around. I myself have much more cells than I have applications for, so I'm not the best person to ask then!

Hello ColtRifle,

You do not need to completely discharge NiMh cells each time you use them, unless your charger only utilizes a timer to terminate the charge. A complete discharge cycle is good to do once every 20-30 charge cycles.

It does not hurt to discharge every time, it just uses up cycle life and extends the charging time.

Tom

Hello Zespectre,

If you had replaced your 1400 mAh cells with similar cells, you could probably expect a similar life from them. Since you went for the higher capacity cells with very thin separators, you may want to expect less... or be disappointed, but you will get longer run time.

Tom