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lbbss wrote:
> I have NiMH batteries and have both Quick charger and slow Energizer
> charger. Will I get more charges if I use slow charger? Also will
> it last longer with slow charger? thanks.

It depends on the charger. A proper charger that is able to detect
end-of-charge, even on slow charge, is best. It's easier to detect
end-of-charge on a fast charger.

measekite wrote:
> On Wed, 31 Dec 2008 18:10:44 +1000, Mark Thomas wrote:
>
>> measekite wrote:
>>> On Tue, 30 Dec 2008 18:38:13 -0800, lbbss wrote:
>>>
>>>> I have NiMH batteries and have both Quick charger and slow Energizer
>>>> charger. Will I get more charges if I use slow charger? Also will
>>>> it last longer with slow charger? thanks.
>>> I use 15 min batteries in a Duracell 15 min charger and have not problems
>>> when installing them in a Canon camera.
>>>
>>> However, the issue is when I put the same batteries in a flashlight.
>>> After about 3 weeks of none use they flash light glows very dim and
>>> unusable.
>> Flashlights are one of the worst possible uses for normal NiMh (or NiCd)
>> batteries. That type of battery self-discharges quickly, plus if you
>> accidentally leave the light on and flatten the battery, it will result
>> in polarity reversal and battery damage/death (unless the flashlight is
>> actually designed for rechargables). *Only* use low-self-discharge
>> batteries (Eneloops/hybrids), or non-rechargables in this type of device.
>>
>> As has already been pointed out, slow charging is easier on the battery,
>> but ymmv.
>
> Can you PROPERLY charge an Enloop in a Duracell 15 min charger or do you
> need to get a Sanyo charger?

Can't say for certain, but the fast charger I have (a cheap one that I
very rarely use) says it will do 'all' types of NiMh... You should
check the instructions on both battery and charger. I have used that
charger once on my Eneloops and it worked, but I would not make a habit
of it. I have enough batteries and self-organisation that I normally
never need to fast charge..

Ron Hunter wrote:
> It is logical that faster chargers will shorten battery life. However,
> if it reduces the number of recharges by 75%, then, instead of 500
> recharges, you get only 125. That's about a penny per use/charge cycle.
> Why worry about it if the convenience is significant?

In my case, because it will increase the frequency of failures, and the
number of times you run into battery problems in the field. Why not
just organise your battery usage so that you can afford the longer time?
Using low-self-discharge batteries, there is no reason why you can't
always have at least one set pre-charged and ready to go.

I lament this society where speed and disposability are the priorities..
(O:

On Wed, 31 Dec 2008 11:47:01 -0800, John Navas wrote:

>> Heat build up is very relevant in these batteries if you are using them in a
>> flash gun. I have some "duracell" branded 2650 mAa AA's that get hot enough
>> to switch off my Nikon SB900 after about 15 continious shots and some really
>> cheap (like about 1/3rd the cost) generics rated at 2200 mAh that will let
>> me shoot over twice as many before heat comes into play.
>
> The issue there is the higher internal resistance of the batteries.
> I use and recommend NiCd over NiMH in a flash for just this reason.

Then you should stop using and recommending NiCads over NiMH
cells. Energizer's data sheets show that their NiCd AA cells have
an internal resistance of 35 milliohms (fully charged) and an I.R.
of 45 milliohms (1/2 discharged). Their NiMH AA batteries have
internal resistances of 30 milliohms (fully charged) and 40
milliohms (1/2 discharged). Not a big difference, and the recharge
time is the same in Nikon's speedlights. But the NiCd cells have
much lower capacity than the NiMH cells. Nikon's large speedlights
get 90 full power flashes from 4 NiCd AA cells and from 150 to 165
full power flashes from 2,000 mAh NiMH AA cells and Eneloops, and up
to 190 flashes from four 2,600 mAh NiMH AA cells.

I don't know the internal resistance of Eneloops, but others in
the DPR forums have measured their I.R. and report that it's much
lower than standard NiMH cells, and that this results in their not
getting as hot, both while charging as well as when they're used for
rapid bursts in Nikon's speedlights.

>>
> One thing puzzles me about some people's concerns about getting the most
> life out of batteries. Batteries are the cheapest element by far in
> digital photography. Why not just do what works best for each
> individual's needs and replace batteries as needed? Why miss a wonderful
> chance at a photograph because batteries might be injured by charging
> too fast?
> Allen

Most folks I know avoid the problem by having several sets of batteries
charged up and ready to go.

On Thu, 01 Jan 2009 03:48:16 -0600, Ron Hunter wrote:

> ray wrote:
>> On Tue, 30 Dec 2008 18:38:13 -0800, lbbss wrote:
>>
>>> I have NiMH batteries and have both Quick charger and slow Energizer
>>> charger. Will I get more charges if I use slow charger? Also will
>>> it last longer with slow charger? thanks.
>>
>> The answer to that question will depend a bit on how expensive the
>> chargers are. Cheap 'come with' chargers generally have no smarts and
>> will not do an optimal job of charging your batteries. A more expensive
>> 'smart' charger will make them last as long as possible. Given that
>> you're probably talking about cheap 'dumb' ones, the answer would most
>> likely be that slower is better.
>
> I think your are oversimplifying it. A charger (smart) can be built to
> charge faster, or to get the maximum charge into the battery, or to
> preserved the number of recharges, not, generally, all three. Take the
> chargers made for electric cars. They take a rather long time because
> they want to extend the life of the batteries, rather than recharge as
> fast as possible. Things like 15 minute chargers aren't concerned with
> getting the maximum number of charges, or getting the maximum charge
> possible into the battery, just returning them to a useful charge level
> without destroying the battery.

You are correct - it is an obvious over simplification to show the
generalities.

On Thu, 01 Jan 2009 10:15:08 -0600, Allen wrote:

> One thing puzzles me about some people's concerns about getting the most
> life out of batteries. Batteries are the cheapest element by far in
> digital photography. Why not just do what works best for each
> individual's needs and replace batteries as needed? Why miss a wonderful
> chance at a photograph because batteries might be injured by charging
> too fast?

I don't think that this was addressed in the part of the thread
that I saw, but I agree. Charging takes its toll whether the rate
is fast or slow, and a battery's average performance/capacity over
its lifetime is about the same, whether it was charged quickly or
slowly, the primary difference being its lifetime. If NiMH
batteries cost far more than they do this might be a concern, but
they don't, and it's not, at least for me and thee.

On Thu, 01 Jan 2009 09:21:57 -0800, John Navas wrote:

>> I don't think that this was addressed in the part of the thread
>> that I saw, but I agree. Charging takes its toll whether the rate
>> is fast or slow, and a battery's average performance/capacity over
>> its lifetime is about the same, whether it was charged quickly or
>> slowly, the primary difference being its lifetime. If NiMH
>> batteries cost far more than they do this might be a concern, but
>> they don't, and it's not, at least for me and thee.
>
> The great majority of consumer chargers aren't fast enough to do any
> substantial harm to the batteries.

Thanks for the irrelevant response. Or did you mistakenly assume
that if any fast chargers exist they must have a large market share?


> The only significant risk is from a charger that doesn't sense charge
> completion properly and overcharges the batteries, as when a fast
> NiCd charger is used on NiMH batteries, for which different charge
> completion sensing is needed.

Ah, I recall the good old days, when "Fast" NiCd chargers took
from 5 to 7 hours to recharge 450 and 600mAh NiCd cells. Most of
the fast chargers sold 4 to 5 years ago automatically sensed whether
NiCd or NiMH cells were used. Earlier one allowed you to change a
switch position to tell the charger whether you were using NiCd or
NiMH cells. These days, it's usually assumed that only NiMH cells
are used, and for good reason. Those that think they really need
NiCd batteries (Such as you, for your flash units, although you're
wrong. Did you miss the message that explained all or did your
filter break?) should know where to go to get a compatible charger
if they don't already have one. I have several, and they make
excellent NiMH trickle chargers.

On Thu, 01 Jan 2009 10:56:32 -0800, John "Twitty" Navas wrote:

>> [SNIP]
>
> Into the twit filter you go.

I'd say "your loss", but you lost it long ago. Too bad that you
can't tolerate when it's pointed out that your condescending remarks
are either irrelevant or incorrect. The fuller your filter sack
becomes, the greater your burden. You'll still be corrected as
necessary, and if you don't see the corrections there won't be any
loss as you wouldn't benefit from them even if you could see them.

Stephen Henning wrote:
[]
> NiMH batteries are fairly robust. On the other hand, Lithium
> batteries are light, but they are not robust. The can be destroyed
> by completely discharging. Some brands of lithium batteries are much
> more fragile.

Lithium primary cells or Li-ion rechargeable? To me, the packaging shape
is probably more important - I much prefer the single rectangular cell to
multiple batteries which can be inserted the wrong way round. I like the
lower self-discharge of Li-ion or Eneloops.

David