Aren't rechargeables for high current applications?

(Crossposted, please feel free to trim)


Since the worth of a NiMH rechargeable battery is determined by how
many alkalines you avoid buying and disposing of, what's the point of
low leakage current NiMHs?

In other words. Why would you care if the NiMH still has a charge after
one year? Doesn't that negate the value of being able to recharge the
battery hundreds of times? Why not use an alkaline if it needs to last
for one year?

Or, is ordinary/current NiMH leakage current problematic even for high
current uses, and battery makers are trying to correct that?

Thanks.



--
The first big front wheel rollerblades.
http://www.flickr.com/photos/27532210@N04/3056505603

"John Doe"

Since the worth of a NiMH rechargeable battery is determined by how
many alkalines you avoid buying and disposing of, what's the point of
low leakage current NiMHs?

** Obvious.

The things retain charge for much longer so need less regular attention from
owners and are suitable for use with occasionally used items.


In other words. Why would you care if the NiMH still has a charge after
one year?


** Cos you can use them straight away - fool.


Doesn't that negate the value of being able to recharge the
battery hundreds of times?

** Wot complete insanity is this ?


Why not use an alkaline if it needs to last
for one year?


** A torch or a camera may sit idle for long periods, you do not know WHEN
you are going to need them next - so a rechargeable cell that has a long
charge retention time is a real plus over one that does not.

Fact is, the short and variable self discharge periods of NiCd ( and some
MiMH ) cells is their biggest drawback - resulting in the early demise of
the vast majority of NiCd packs from accidental overcharging the cells that
had longer retention than the others.



....... Phil

John Doe wrote:
(Crossposted, please feel free to trim)


Since the worth of a NiMH rechargeable battery is determined by how
many alkalines you avoid buying and disposing of, what's the point of
low leakage current NiMHs?

For cameras, people may use them only every couple of months for most of
the year, then use it a lot during a couple of weeks, but alkalines
perform especially poorly in cameras due to their high internal resistance.

Yes, for flashlights, alkalines are often fine. But now a lot of people
use LED flashlights as bicycle lights for commuting, needing to charge
then often.

Low leakage NiMH batteries are pretty cheap now, on sale they're around
$1.50, so they're only about 2x the price of name brand AA alkalines at
Costco.
\

Suspicious self serving post.

Since the worth of a NiMH rechargeable battery is determined by how
many alkalines you avoid buying and disposing of,

I think you've just sandbagged the discussion, by asserting (as a
given) that one specific measure of the "worth" of a battery is *the*
worth.

It isn't. That's only your own personal judgement.

what's the point of
low leakage current NiMHs?

I think you would get a more useful set of answers if you were to
phrase your question in a more open-minded way, as in

"What do you, the user of a low-leakage NiMH battery, see as its
advantages and disadvantages compared with other battery types?"

In other words. Why would you care if the NiMH still has a charge after
one year? Doesn't that negate the value of being able to recharge the
battery hundreds of times? Why not use an alkaline if it needs to last
for one year?

[1] The high current delivery capability is valuable in the applications
in question. One primary application, for me, is ham radio...
specifically, emergency communications service. Although I *can*
run my HTs on alkaline batteries (and I keep a brick of 'em
around as a backup), pulling over an amp out of 'em during
transmission will kill them pretty quickly. I get more run-hours
per battery-pack-full with NiMH than I do with alkalines.

Same is true for digital camera applications.

[2] The fact that these applications are "high current" does not imply
"use 'em every day or two". I may pull out my ham-radio go kit
for an actual event (or for drill) only every couple of months.
When I do, I want the radio batteries to be available *right*
*away*... the start of an emergency is exactly the wrong time
to have to worry about recharging (or changing out) weak batteries.

Ditto for my wife's point&shoot digital cameras. She sometimes
doesn't use them for days or weeks at a time... but if she does, and
the batteries go dead, I hear about it (especially if she misses an
important shot!).

[3] Alkalines have an annoying tendency to leak, especially if partially
discharged and then left sitting in the equipment for some months.
Although the leakage isn't horribly corrosive, it's messy and
annoying. In order to avoid this, I've found it desirable to change
out alkalines before putting equipment into storage, even if only
a small fraction of the charge has been used... this strikes me as
wasteful.

I have not noticed any similar tendency of nickel-based
rechargeables to leak.

[4] Cost savings. If a low-discharge NiMH pays for itself after, say,
8 alkaline AA's not purchased, then every further alkaline not
purchased/used/discarded is money in my pocket.

Why should I think it "negates" the value of being able to
recharge the battery (and save money) hundreds of times, if it
takes years to accomplish this at my current rate of use rather
than months? It's still money saved, and waste not generated!

So, by comparison with other battery types:

[A] I could use alkalines. I wouldn't get as much run time per
set, I'd have to carry more with me, I'd have to wait longer
between photos (or use my radio at a lower transmitter power
output level), I'd have to be more concerned about leaks during
storage. In the short term I'd pay less money (no charger
to buy), but in the long term it'd be more expensive.

[b] I could use very-high-capacity, higher-discharge NiMH batteries.
They'd be good for "charge and use within a few days"
applications... but beyond that horizon they might actually
retain less useful charge than the lower-rated-capacity low-
self-discharge type.

[C] I could use NiCd batteries. Substantially lower capacity,
hence less run time per set, and their self-discharge rate might
not be any lower than the best low-discharge NiMH these days.

[D] I could use lithium AA primary cells. Excellent current delivery,
low internal resistance, high capacity, light... but they are
*not* inexpensive. The cost is about the same as low-self-
discharge NiMH, but they're single-use-only. I buy these for
my wife's cameras when we go on vacation (she prefers to travel
with as little and as light baggage as possible) where the
convenience is worth the high cost.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Do you insult people in person like you insult people over the
Internet, Phil? Were you an orphan? Don't know about the average
Australian, but seems there are a few too many like Phil (another
Australian foul mouth apparently with no self control is Rod Speed
in the storage group). I'm genuinely curious. Maybe they come from
some small backwards tribal region, like where their customs are the
reverse of normal people.


"Phil Allison" philallison tpg.com.au wrote:

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From: "Phil Allison" philallison tpg.com.au
Newsgroups: rec.photo.digital,sci.electronics.design
Subject: Aren't rechargeables for high current applications?
Date: Fri, 5 Dec 2008 12:47:53 +1100
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"John Doe"

Since the worth of a NiMH rechargeable battery is determined by how
many alkalines you avoid buying and disposing of, what's the point of
low leakage current NiMHs?

** Obvious.

The things retain charge for much longer so need less regular attention from
owners and are suitable for use with occasionally used items.


In other words. Why would you care if the NiMH still has a charge after
one year?


** Cos you can use them straight away - fool.


Doesn't that negate the value of being able to recharge the
battery hundreds of times?

** Wot complete insanity is this ?


Why not use an alkaline if it needs to last
for one year?


** A torch or a camera may sit idle for long periods, you do not know WHEN
you are going to need them next - so a rechargeable cell that has a long
charge retention time is a real plus over one that does not.

Fact is, the short and variable self discharge periods of NiCd ( and some
MiMH ) cells is their biggest drawback - resulting in the early demise of
the vast majority of NiCd packs from accidental overcharging the cells that
had longer retention than the others.



...... Phil









--
The first big front wheel rollerblades.
http://www.flickr.com/photos/27532210 N04/3056505603
Google Groups is destroying the USENET archive.

"John Doe"

( snip load of top posted, puerile drivel)


** Anyone as colossally stupid as YOU pal, needs to develop a thicker
hide.


**** off - fool.


...... Phil

John Doe wrote:
(Crossposted, please feel free to trim)


Since the worth of a NiMH rechargeable battery is determined by how
many alkalines you avoid buying and disposing of, what's the point
of
low leakage current NiMHs?

In other words. Why would you care if the NiMH still has a charge
after one year? Doesn't that negate the value of being able to
recharge the battery hundreds of times? Why not use an alkaline if
it
needs to last for one year?

It's bloody inconvenient to have your clock or keyboard run down after
3 monts because of internal leakage in the battery.

Or, is ordinary/current NiMH leakage current problematic even for
high
current uses, and battery makers are trying to correct that?

Thanks.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

"Phil Allison" wrote:
"John Doe"

( snip load of top posted, puerile drivel)

Appears to be a same dialect. Okay, so I see Phil is obsessed with
Sylvia in the Australian legal group. So maybe Phil and Rod are the
same, or brothers, or maybe bedfellows.

** Anyone as colossally stupid as YOU pal, needs to develop a
thicker hide.

Do you have a Crocodile Dundee complex, Phil?

**** off - fool.

Are you in a movie, Phil?



















..... Phil



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From: "Phil Allison"
Newsgroups: rec.photo.digital,sci.electronics.design
Subject: Aren't rechargeables for high current applications?
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"John Dope"

( snip another whole load of top posted, puerile drivel )


** Anyone as monumentally stupid as YOU pal, needs to develop a very thick
hide.

To go with that very think head of yours.

**** the hell off - you PITA trolling ****wit.