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Old Jul 25, 2008, 9:22 PM   #1
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How long should it take to discharge a set of batteries in the charger? I assume it depends partially on how much charge is left but I have tried and it seemed to take forever. I have a C204 charger.

Since it's recommended to discharge them when you first get them and do a few times thereafter to hold a full charge, is it really necessary? Do all batteries require this cycle? Thanks.
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Old Jul 25, 2008, 9:38 PM   #2
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Hello Picsgalore,

I believe that charger discharges at around 200 mA. That means that for a 2000 mAh cell, fully charged, it would take around 5 hours to discharge.

If your application only involves single cells, you probably don't need to cycle or break in your cells. On the other hand, if your application involves using multiple cells, you will get better performance if you take the time to break them in.

Many people simply use their cells, and then complain when the performance drops...

Tom
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Old Jul 25, 2008, 9:55 PM   #3
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SilverFoxCPF,

Thanks for the quick response.Being a non tech person I'm not sure I know what you mean about my application being a single cell etc.! Does that mean one set of AA's? If so, then yes and it's for the Sony H5 camera.

I never seemed to get anywhere near the number of images taken before getting the low battery icon in the LCD or viewfinder. However, I do use the LCD most of the time.

Should I also discharge the Eneloop batteries or is it not necessary for those?

Thanks again.
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Old Jul 25, 2008, 10:52 PM   #4
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SilverFox,

No need to reply about the Eneloops. I found the answer on Sanyo's web site as stated here-I would still like your response to the rest of my previous reply and questions. Thanks.

Memory Effect [align=left][/align]
Eneloop, like other nickel metal hydride (NiMH) rechargeable batteries, have negligible memory and do not need to be fully discharged before recharging.

[align=right][/align]
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Old Jul 27, 2008, 3:48 PM   #5
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Hello Picsgalore,

An application that involves a single cell only uses one battery. Think of a small flashlight.

I think most cameras use 2 - 4 batteries, so they are not a single cell application.

When you use multiple batteries, the whole set is only as good as the weakest cell. When charging NiMh cells in the C204 charger, the cells are charged in pairs. If one cell signals the end of charge before the other cell is fully charged, one cell will end up under charged and will be the weakest cell.

People have moved to chargers that charge each cell independently to eliminate this problem. I believe the C401 chargers are independent channel chargers as is the C9000.

With new batteries, there isn't much of a problem, but as the cells age an imbalanced condition can develop. With imbalanced cells you end up with poor performance, i.e. fewer shots from your camera.

The C204 charger does have a healthy trickle charge so you should be able to balance the cells by simply leaving the cells on the charger after the charge has completed. The problem is figuring out how long to leave them trickle charging.

Let's look at an example...

If you had 2000 mAh cells, and one of them had around a 15% imbalance, this would mean that it would only have about 1700 mAh of capacity. If this cell was used in a set of other cells, it would crap out first. To get the rest of the 300 mAh of capacity into the cell during the trickle charge after the main charge, it would take over 11 hours.

You might ask, "Why not just leave the cells in the charger all the time?" when you are not using them. The answer is that extended trickle charging kills NiMh cells.

Here is what you can try.

Put your cells in the charger and let them charge for 24 hours. Depending on use, you need to do this about every 20 charge/discharge cycles, or you can do it 2 - 4 times a year. It is easy to remember to balance your cells just before the holidays at Christmas, and just as summer starts.

Please understand that imbalance is the most common cause of poor performance, but there are other causes as well. Sometimes cells just go bad.

Tom
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Old Jul 27, 2008, 5:33 PM   #6
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SilverFox Tom,

Thanks very much. I have learned much here thanks to you. I'll have to look at new chargers. Never knew that about the C204.

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