Speaking of Rechargable Batteries

[Don Schaeffer]

My NIMH batteries used to work fine on my point and shoot cameras. However, lately I find the fully charged batteries can only power the cameras for a few shots. Alkaline batteries are working fine--it's most embarrassing after I've been touting rechargble batteries to my friends. Does anyone have any idea what could be happening here?

[WesternGuy]

My NIMH batteries used to work fine on my point and shoot cameras. However, lately I find the fully charged batteries can only power the cameras for a few shots. Alkaline batteries are working fine--it's most embarrassing after I've been touting rechargble batteries to my friends. Does anyone have any idea what could be happening here?

Don, my first question is - how old are the batteries? Rechargeables do lose their ability to retain a charge as they get older. As well, they lose about 30% of their charge monthly, if not in use (depending on the temperature they are stored at) and they are good for somewhere between 500 to 1000 charge-discharge cycles. If they are only used occassionally and recharged after each use, then they are known to suffer from something called "voltage depletion" , which requires that they be almost completely discharged every once in a while and then fully recharged. Most NiMH batteries only charge to about 1.2 volts when compared to the 1.5 volts of regular NiMH and alkaline batteries. Some devices will work okay at the reduced voltage, for example, if you use 4 NiMH charged at 1.2 V then this is 4.8V in total whereas with regular batteries at 1.5 V, you have 6 V total. Some devices will tolerate this discrepancy, but as the rechargeables get older, they may not be able to hold the 1.2 V charge as long and if they drop below, say 1.0 V, then your P&S may not work at this low a voltage, even though the batteries still have enough voltage in them to power somthing like a flashlight.

When you say that "alkakine batteries are working fine", do you mean straight, run-of-the-mill, off the shelf alkalines, or are you talking about alkaline rechargeables. Regular alkalines will work fine when new, but they apparently do not last as long as good, rechargeable, NiMH, so it is understandable that new alkaline batteries would last longer relative to old NiMH which may be near the end of their useful life - not sure if this is the situation in your case.

I am not sure if this answers your question, but I hope it helps. Maybe others have some alternative explanation which they would care to share.

Regards,

WesternGuy

[freygr]

How old are they and how many charges? The batteries do ware out losing a little capacity each charge cycle. I had a set of 650mah batteries last 5 years before they had to be replaced. You can recharge the batteries many times before they will need replacement depended on how they are used(load) and other factors. The number of charges varies too much but can range from less than 100 to over 500 times.

If there are newer batteries you need to fully discharge them before charging this may restore some of the old capacity.

Note if the charger is overcharging the batteries, the batteries will die fast (batteries will need to be replaced before there time)

[Don Schaeffer]

That's the answer I'm sure. The batteries are at least a couple of years old and not used for a while. I'll but a new set.

[WesternGuy]

That's the answer I'm sure. The batteries are at least a couple of years old and not used for a while. I'll but a new set.

Don, please let us know if, in fact, that is/was the answer - old batteries. I, for one, would be very interested to see if that solved the problem. Thanks.

Cheers,

WesternGuy

[Don Schaeffer]

ok. Thanks guy. Will report back.

[freygr]

Also Cool weather can degrade the storage capacity of rechargeable batteries.

[SmartWombat]

I recommend the Maha MH-C9000 charger/analyser.
You can use it to test a set of batteries and find out what their capacity is today, as well as cycle them to try to restore their capacity if they've stood idle for too long.

[Don Schaeffer]

thanks freyer and Wombat