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Old Apr 10, 2005, 1:34 PM   #1
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I had a set of MAHA PowerEx double-A batteries with current rated at 1800 mA, and according to the charger, they were charged. According to my basic Radio Shack battery tester, they were charged. Yet, when I tried putting into my Olympus D560-Zoom, the camera refused to power on. It considered the batteries dead. The camera's specs do not say much about the amperage. The camera still accepts alkaline batteries, but like most digital cameras, it drained the usable portion of the batteries in about 12 hi-res shots.

Has anybody ran into this type of problem? Does the amperage matter (can you really stick in a 2000+ mA battery without damaging the camera?)?
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Old Apr 10, 2005, 7:11 PM   #2
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AA NiMh type batteries go up to 2500 and 3600mAh now. See my NiMH Batteries page for a rundown of popular brands and of chargers - the new Energizer 2500mAh batteries really last a long time. As important as the battery, the charger is next to consider as many do not fully charge the cells. The new LaCrosse BC-900 is amazing and never fails to fully recharge cells no matter what their rating is - and it can recover older cells that aren't working well due to numerous charge cycles that less than fully recharged the cells.

You can use any capacity cells, the higher the rating the longer they last and the newer NiMH technology and chemistry is better than the old stuff.
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Old Apr 10, 2005, 7:46 PM   #3
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The battery rating is mAH,( milliamp-hours). It is a capacity rating. Your camera can't tell the difference, as all it senses is the voltage. There is a slight difference in voltage between NiMH and alkaline batteries, with alkaline being higher. alkalines have a gradual dropoff in voltage as they discharge, where the NiMH remain at nearly the same voltage until they are almost fully discharged. Alkalines considered by a digicam to be dead still have about half of their power remaining.

If the NiMH cells are new, try discharging them by using in a flashlight, then recharging. New batts sometimes need a cycle or two to get up to full charge. Also, check the ends of the batts for dirt or corrosion. Clean with a soft cloth if needed. Check the connectors in the camera's battery compartment for cleanliness as well. Dirt in these areas can cause a little bit of votage drop, and that is sometimes all that is needed for the cam to think the batt is dead.

If none of this works, the camera's votage sensor may need adjusting, which is a job for sevice department.

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Old Apr 10, 2005, 8:45 PM   #4
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Thanks for the explanation on batteries. I'll check the batteries out on a full discharge/recharge cycle and see whether the camera's voltage sensor is bad.
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Old Apr 11, 2005, 11:52 AM   #5
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Ok, I tried it with a pair of Kodak Max batteries, and I think it was what VTphotog said. The original PowerEX may have not been fully charged.

I went ahead and ordered the LaCrosse charger, but I'm probably going to have to find a better camera in the near future anyway.
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Old Apr 13, 2005, 10:38 PM   #6
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The cameras must evaluate the amperes of a battery somehow, not just the voltage. After a discharge cycle in my camera, the batteries all read around 1.25v. I put them back in and tried another cycle. The cycleonly lasted about 20 seconds and the camera shut down. I re-metered the batteries and they still read around 1.25v.

Metering the voltage of a NiMH battery is not a good indicator of it's state of charge based on the label volts.
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Old Apr 14, 2005, 1:11 AM   #7
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The camera is reading voltage continuously, so when it sees the voltage drop slightly under load, it considers the batts discharged.

The internal resistance is partly determined by the state of charge, so that under load, some part of the voltage in the circuit is dropped in the battery itself. If the battery terminals are corroded or dirty, additional voltage is lost here. The camera measures the remaining voltage. As the battery nears the end of its charge, the internal resistance increases, causing more voltage drop, and the camera knows the battery is going to quit soon.

If the characteristic discharge curve is known, then cell voltage under load is a reliable test for remaining charge. This is how (most) battery testers work.

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Old Apr 14, 2005, 4:09 AM   #8
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"The cameras must evaluate the amperes of a battery somehow, not just the voltage."

What a lot of rubbish. Batteries dont have amperages. They do as vtphotog says, have a capacity of milli amp hours. Pay attention to what he & Steve says, it's all good stuff.

Of course CCWKen, "metering" a battery as you describe without it being loaded is pointless. You need to 'load' the battery with a typical load, such as say a digi camera. That could be up to 1000ma. The voltage results will be very different.
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