Which charger to use

On Fri, 20 Oct 2006 00:13:44 GMT, quess who wrote:

> I have a collection of AA NI-MH batteries of various mA ratings. 1850,
> 2000, 2300, 2500 and I am thinking of getting some Maha Powerex
> 2700mA.
>
> The chargers I have are made by Energizer(15min charger), PowerMart (1
> hr charger), and an old Radio Shack 1hr charger.
>
> Can I use the same charger for all of these amperages with the end
> result that they will all be charged to their individual maximum
> capacity?

Your chargers should all work properly for all of these batteries
with one exception. If any of the chargers has a protective
time-out circuit, the highest capacity batteries, if fully
discharged *might* trigger the time-out before they're fully
charged. But this is pretty unlikely, as most of the cut off times
I've seen have been well beyond the time it would take to charge
batteries. When you get the 2,700 mAh batteries, monitor how long
it takes to charge them when they're fully depleted. It should take
slightly longer than when the same test is performed with your 2,500
and 2,300 mAh batteries. If it takes significantly longer (say 40%
longer), then your old batteries have lost a lot of capacity and you
might want to use them for radios or something, but not in your
camera, unless you tend to take a fairly small number of pictures
whenever you use your camera.
 >> Stay informed about: Which charger to use 

On Oct 19, 5:13 pm, quess who <nob... RemoveThis @somewhere.com> wrote:
> I have a collection of AA NI-MH batteries of various mA ratings. 1850,
> 2000, 2300, 2500 and I am thinking of getting some Maha Powerex
> 2700mA.
>
> The chargers I have are made by Energizer(15min charger), PowerMart (1
> hr charger), and an old Radio Shack 1hr charger.
>
> Can I use the same charger for all of these amperages with the end
> result that they will all be charged to their individual maximum
> capacity?

One 'danger' is whether or not the charger inputs electricity at too
rapid a rate for the batteries to accept. Some batteries must be
charged at a lower rate unless they are designed for rapid charging.

Another issue is if the charger is optimized for the chemistry of the
battery...Chargers for NiCad have different operating characteristics
and charge characteristics than chargers for NiMH batteries.
 >> Stay informed about: Which charger to use 

In article <1161363924.814891.173260 DeleteThis @i3g2000cwc.googlegroups.com>,
"wilt" <wiltw DeleteThis @aol.com> wrote:

> On Oct 19, 5:13 pm, quess who <nob... DeleteThis @somewhere.com> wrote:
> > I have a collection of AA NI-MH batteries of various mA ratings. 1850,
> > 2000, 2300, 2500 and I am thinking of getting some Maha Powerex
> > 2700mA.
> >
> > The chargers I have are made by Energizer(15min charger), PowerMart (1
> > hr charger), and an old Radio Shack 1hr charger.
> >
> > Can I use the same charger for all of these amperages with the end
> > result that they will all be charged to their individual maximum
> > capacity?
>
> One 'danger' is whether or not the charger inputs electricity at too
> rapid a rate for the batteries to accept. Some batteries must be
> charged at a lower rate unless they are designed for rapid charging.
>
> Another issue is if the charger is optimized for the chemistry of the
> battery...Chargers for NiCad have different operating characteristics
> and charge characteristics than chargers for NiMH batteries.

No. The real danger is are the cells you use designed for fast charging?
If they aren't they can't vent the gasses built up during charging and
then can explode or catch on fire.

Recent quality NiMh cells will be marked that they are safe for rapid or
fast charging.

As a general rule of thumb, any real cell with a capacity of 2000 mAh or
more (not simply re-labled cells where the higher capacity exists only
on the printing on the label, can be safely fast or rapid charged.

Smaller cells will have a problem with fast charging. This includes
cells that are simply relabeled with a high capacity.

If your cell or its package is not labeled for fast or rapid charge
don''t fast or rapid charge them.

--
To reply no_ HPMarketing Corp.
 >> Stay informed about: Which charger to use 

ASAAR wrote:
> On Fri, 20 Oct 2006 00:13:44 GMT, quess who wrote:
>
>> I have a collection of AA NI-MH batteries of various mA ratings. 1850,
>> 2000, 2300, 2500 and I am thinking of getting some Maha Powerex
>> 2700mA.
>>
>> The chargers I have are made by Energizer(15min charger), PowerMart (1
>> hr charger), and an old Radio Shack 1hr charger.
>>
>> Can I use the same charger for all of these amperages with the end
>> result that they will all be charged to their individual maximum
>> capacity?
>
> Your chargers should all work properly for all of these batteries
> with one exception. If any of the chargers has a protective
> time-out circuit, the highest capacity batteries, if fully
> discharged *might* trigger the time-out before they're fully
> charged. But this is pretty unlikely, as most of the cut off times
> I've seen have been well beyond the time it would take to charge
> batteries. When you get the 2,700 mAh batteries, monitor how long
> it takes to charge them when they're fully depleted. It should take
> slightly longer than when the same test is performed with your 2,500
> and 2,300 mAh batteries. If it takes significantly longer (say 40%
> longer), then your old batteries have lost a lot of capacity and you
> might want to use them for radios or something, but not in your
> camera, unless you tend to take a fairly small number of pictures
> whenever you use your camera.
>
My first purchase was an inexpensive smart charger that came with 4
cells, charges 2 or 4 at a time. These work well, but I upgraded to this.
Before postage, this one at less than $23
http://www.greenbatteries.com/nibachwilcdd.html
is a bargain, although not so much so when postage is added. It seems to
work well, shows charging progress and will charge 1 to 4 cells. I would
be wary of the 15 minute charger on cells other than those for which it
is designed, just keep an eye on how hot the cells get.
Dave Cohen
 >> Stay informed about: Which charger to use 

On Fri, 20 Oct 2006 17:08:43 GMT, Dave Cohen wrote:

> My first purchase was an inexpensive smart charger that came with 4
> cells, charges 2 or 4 at a time. These work well, but I upgraded to this.
> Before postage, this one at less than $23
> http://www.greenbatteries.com/nibachwilcdd.html
> is a bargain, although not so much so when postage is added. It seems to
> work well, shows charging progress and will charge 1 to 4 cells. I would
> be wary of the 15 minute charger on cells other than those for which it
> is designed, just keep an eye on how hot the cells get.

I almost always recommend smart chargers that can charge any
number of, or combination of cell types. In this case I didn't,
because the OP asked a fairly specific question that had nothing to
do with whether a charger is limited to charging pairs of cells or
not. But it's a good point to remember. One other problem those 15
minute chargers may create is related to the heat they produce.
I've seen that in some electrical devices that don't have a lot of
tolerance in their battery compartments that some batteries are a
bit too fat to remove easily if they have to slide in where fingers
can't grab them. This has never been a problem with alkaline
batteries. It is a problem with NiMH cells, where removal can
sometimes be difficult. As far as I'm aware, it has also never been
a problem with new NiMH cells, so something is making them obese,
and I suspect that the more times they're charged, the fatter they
get. Just guessing, but I'd assume that the chargers that heat the
batteries the most would be the guiltiest culprits.
 >> Stay informed about: Which charger to use 

Thanks to all who responded. My question was answered very well.

On Fri, 20 Oct 2006 00:13:44 GMT, quess who <nobody.TakeThisOut@somewhere.com>
wrote:

>I have a collection of AA NI-MH batteries of various mA ratings. 1850,
>2000, 2300, 2500 and I am thinking of getting some Maha Powerex
>2700mA.
>
>The chargers I have are made by Energizer(15min charger), PowerMart (1
>hr charger), and an old Radio Shack 1hr charger.
>
>Can I use the same charger for all of these amperages with the end
>result that they will all be charged to their individual maximum
>capacity?
>
>
 >> Stay informed about: Which charger to use