Re:Do rechargeable batteries "go bad"?

[Michele Stapleton]

The rechargeables will take so many charges and then fail to hold  
their power. But they don't damage the unit they are powering, they  
just fail to hold their power.


Michele


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Michele Stapleton: photographer
BRUNSWICK, MAINE
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[Peter Bennett-8]

> From: Michele Stapleton <Michele@...>
>  
>
> The rechargeables will take so many charges and then fail to hold
> their power. But they don't damage the unit they are powering, they
> just fail to hold their power.
>
> Michele

Important point, I¹ve never heard of such a thing. And not only will
rechargeable batteries save you a bunch of money over time, the
environmental impact is substantially lower. I use them I my Canon 580 unit
and they work great. I would advise that you get a good re-charger and of
possible it should have an indicator to let you know when the charge is
complete.

Peter Bennett
Ambient Images Inc.
P: 310-312-6640

Specializing in New York and California images
http://www.californiastockphoto.com
http://www.newyorkstockphoto.com
http://www.greenstockphotos.com

[David Riecks]

At 07:07 AM 9/18/2009, Michele Stapleton wrote:
>The rechargeables will take so many charges and then fail to hold
>their power. But they don't damage the unit they are powering,

Michele:

I agree. I've used rechargeable batteries for years. Many of the
earlier versions were (and still are) about a quarter or more less
voltage (1.15, or 1.25 volts rather than 1.5 volts. For a unit using
four batteries that means you are starting out with only 4.6 or 5
volts rather than 6. With some instruments that might mean a shorter
use time between charges, but I can't see that damaging the unit in
which they are used. Most devices that have a 6 volt battery pack
will be able to work with less than that voltage.

Many of the rechargeables have differences in terms of their milli
ampere rating, and this has much to do with hold long they can hold a
charge or deliver power.

Like Bob and Peter have said, most batteries, especially Lithium Ion
ones, have a specific battery life.  I know that Dell tech support
knows this. I had to finally replace the battery in my previous D600
laptop after about 2 years as I was down to two active cells out of
six!  This meant I only got about 45 minutes between chargings rather
than the 2 to 2.5 hours I had gotten in the beginning. This was only
a problem at conferences, since I typically plug it in whenever I'm
near a power source.  Dell actually states that you get about 300
full discharges before you'll experience a marked shift in
performance. I would suspect that the latest round of rechargeable
batteries have a similar capacity for recharge as well. To get the
most, always have a backup set, and always drain down the batteries
to their maximum before recharging.

David

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[Non-text portions of this message have been removed]

[newuncleme]

There are two kinds of NiMH I see in AA and AAA lately.  The first type can have higher mAH but when sitting unused, self discharges fairly quickly.  The higher amperage means more power when fully charged though.  For AA's I look for about 2700mAH.  Rated power capacity is either true or false, so look for quality batteries from a good manufacturer.  Assuming truthful specs though, 2700 is better than 2000.

The other type typically has lower initial mAH, but holds a charge much longer -- good for hand-controllers and smoke alarms and emergency flashlights.  Eneloops and others of this type may come already charged, but rate at 2000 mAH.  

Modern battery types, Lithium and NiMH will suffer, overheat, be ruined or damaged if you try to EVER "drain down ... to their maximum before recharging."  The very best cells of these types will clamp down and not release more current at about 20% of their rated capacity, but this is usually when used in certain devices, like a laptop.  Older NiCads had such great memory issues that if didn't follow this advice, their life shortened significantly.  Newer NiCads may benefit from conditioning cycles.

/..


<...>
>To get the
> most, always have a backup set, and always drain down the batteries
> to their maximum before recharging.
>
> David