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Ok to leave battery in charger?


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I don't spend a lot of time staring at my battery charger, but I took a look at it today and I noticed that the green "power" LED was lit when the battery was in the charger but the charger was unplugged. I assume this is supposed to be a feature, a way to quickly check if the battery has juice. But it made me wonder: should I not be storing an extra battery in the charger? Will it drain or reduce the battery's life? I usually keep a battery in there because the charger is so big that I know I won't lose the battery :cool:

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I don't spend a lot of time staring at my battery charger, but I took a look at it today and I noticed that the green "power" LED was lit when the battery was in the charger but the charger was unplugged. I assume this is supposed to be a feature, a way to quickly check if the battery has juice. But it made me wonder: should I not be storing an extra battery in the charger? Will it drain or reduce the battery's life? I usually keep a battery in there because the charger is so big that I know I won't lose the battery :cool:

I have noted this as well

I suspect very little is drained by the LED, but I tend to take mine out as soon as I dismount the charger

OT comment for the folks in Solms who might be reading this: I hope Leica comes out with a less bulky charger for travel

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I usually leave the battery in the charger after it has finished charging. But that is because I am not where the charger is or I'm asleep. In other words I put the battery in the charger at night and then go to bed or like today I put a battery in the charger before I went to work.

 

But I do not unplug the charger from the wall with a battery in it. If I do unplug the charger from the wall I take the battery out before I do that.

Normally I just leave the charger plugged in all the time and then insert batteries into it as needed.

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Yes, the battery does drain, but not quickly. It's best to remove the battery from the charger when the charging cycle is complete.

 

Mark

 

Are you sure that is true? I always leave my battery in the charger after the charging cycle is complete. I assumed it did no harm and just kept it fully charged. However, no battery stays in there for more than a week before being used.

On the other hand, I have heard of people storing their charged batteries in the refrigerator. Sounds like a good way to loose track of batteries.

 

Rex

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Rex,

 

Unlike Ni-Cads, Li-Ion batteries are not trickle charged, so keeping it in the charger is not going to keep it "topped up". The charge controller chip takes the battery through a prescribed charging cycle which ends with constant voltage and declining current. When the current reaches about 10% of the starting current, the charge is switched off to prevent the battery over-charging. The charger also monitors battery temperature and will shut off if the charging goes outside a safe area of operation.

 

That's one reason why there are so many patterns of batteries. They are there to make sure the battery is only charged by a charger which is matched to the characteristics of the battery. If the new charger has interchangeable plates/battery pack holders, I expect it will sense the type of plate to adjust the charging characteristics.

 

With the standard Leica charger, there's a small current drain back through the charger (I haven't measured it) which results in the green LED lighting dimly.

 

As regards keeping batteries in the refrigerator, Li-Ion battteries should be bought to be used, not for "stock", because their capacity declines over time whether or not they are used. This process can be minimised by storing batteries approximately half-charged in a refrigerator which effectively slows the rate of the internal discharge and the chemical reaction which is depleting the capacity.

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Rex,

 

Unlike Ni-Cads, Li-Ion batteries are not trickle charged, so keeping it in the charger is not going to keep it "topped up". The charge controller chip takes the battery through a prescribed charging cycle which ends with constant voltage and declining current. When the current reaches about 10% of the starting current, the charge is switched off to prevent the battery over-charging. The charger also monitors battery temperature and will shut off if the charging goes outside a safe area of operation.

 

That's one reason why there are so many patterns of batteries. They are there to make sure the battery is only charged by a charger which is matched to the characteristics of the battery. If the new charger has interchangeable plates/battery pack holders, I expect it will sense the type of plate to adjust the charging characteristics.

 

With the standard Leica charger, there's a small current drain back through the charger (I haven't measured it) which results in the green LED lighting dimly.

 

As regards keeping batteries in the refrigerator, Li-Ion battteries should be bought to be used, not for "stock", because their capacity declines over time whether or not they are used. This process can be minimised by storing batteries approximately half-charged in a refrigerator which effectively slows the rate of the internal discharge and the chemical reaction which is depleting the capacity.

 

Mark,

 

As always, your technical explanation is helpful. I had assumed that the battery required a trickle charge to stay "topped off" as in the old days of ni-cads. By the way, most of us old guys have a habit of thinking of battery characteristics in terms of either lead-acid or ni-cad. It's a hard habit to break.

 

But you didn't answer my practical question of whether it does any real harm to leave the battery in the charger if you use it every week or so. It is more convienent to leave the charger plugged in with a battery installed. That way I know where the extra battery is at all times.

 

Rex

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With the standard Leica charger, there's a small current drain back through the charger (I haven't measured it) which results in the green LED lighting dimly.

 

 

That is IF the charger is uplugged from the wall with the battery still inserted in it.

To me this sounds wrong, not that it doesn't happen. But there should be a separation between the battery and the actual charging and line in, AC, circuit.

I know for a fact that if I unplug my Nikon charger for the D200 battery with a battery left in the charger there is no feedback through the AC line and that no light on the charger comes on in any way.

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Rex, a charger can monitor the voltage of the charged battery and start a new new (short lived) charge cycle if it falls; what doesn't happen though is that the battery is continually fed with a small current which is what happens in a Ni-Cad battery. I don't believe the Leica charger will start a new cycle until the AC power is interrupted or the battery is removed (that is, the monitored voltage falls to 0).

 

To be fair, I have not measured the current drain and cannot say whether it happens when the charger is plugged in and supplying power to the circuit. It does happen when the charger is unplugged. I don't think there are any ill-effects leaving the battery in the charger but no particular benefits either.

 

Ed, the green LED is indeed on the low voltage side of the circuit, electrically isolated from the high voltage side.

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