Rechargable Alkalines

Are the rayovac rechargable batteries any good for LED flashlights?
Just wondering as that would probably be more cost effective in the long run.
BTW, I would mainly use these on a 18LED light AA light and a AAA LS.

The rechargable alkalines have one
advantage over the rechargable NiCd's and
the newer NiMH batteries:
They dont have that aweful self discharge
problem.
This is about the only advantage you can
find. The alkalines dont discharge even
after a fairly long time, so if you have
an application that has to have a battery
that cant be recharged often, you might
wish to consider using a rechargable
alkaline. They dont recharge as many times
as a NiCd or NiMH cell either. Maybe
about 10 to 20 times depending on how
low you let the voltage get before recharging.
NiCd's recharge about 500 times or more.
So you have to decide for whatever
application you might have.

--Al

Good points, Mr.Al
In using Rayo. Renewals for 5-6 years, I've found that if I use them only down to about 50%, they will recharge very well for 50-70 good recharges. As you've said, they're particularly effective with
lighter drains like LEDs.

In my 2 years or so of using the Nimh cells I have not found their self-discharge too much of a problem. -It should be remembered that these cells only lose a % of their remaining charge each day, (a LOT like radio-isotopes do). This was pointed out by CPF member "battery guy" a while back. As an example, I have used NimH AAAs in my UKE Keyring light, and the batteries still had a respectable amount of power after having been carried in my pocket after more than 10 months without recharge.
-So, as self-discharge does progress, the losses get proportionately smaller as time goes on.....
But, as you know, all rechargeables (except rech.alks) are sure a poor choice for emergency flashlights that only get used occasionally.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by videocal:
As an example, I have used NimH AAAs in my UKE Keyring light, and the batteries still had a respectable amount of power after having been carried in my pocket after more than 10 months without recharge<HR></BLOCKQUOTE>

Carrying in your pocket makes it worse as they stay at higher temp as ambient (at least around here). So ourside it should be even less of a problem.
But cells are different and older cells have a much higher self discharge.
Even 'rechargeable' alkalines have a higher self discharge compared with normal alkalines.

So are rechargable Alkalines comparable to normal Alkalines?
As in burn time for LED flashlights.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Elmie:
So are rechargeable Alkaline comparable to normal Alkaline?
As in burn time for LED flashlights.<HR></BLOCKQUOTE>

Their capacity drops with each charge/discharge cycle, but even the first cycle has less capacity than a standard alkaline.

Rechargeable alkaline's tendency to leak or explode seem higher than almost any other type of battery- use at your own risk!

Link to previous CPF thread on batteries.

Peter

That's an interesting link to that thread
on batteries.

I have read that the NiMH cells have twice
the self discharge as the NiCd's. Now
maybe this isnt that much when the cell is
brand new, but once the cell gets older
it becomes a pain because the batteries
need recharging every month

I'll have to pick up a set of the NiMH cells
one of these days and see for myself. So
far every place i have found them they were
overpriced. I'll wait till i find them for
a decent price first.

Also, in that thread and other places on the
web i have read what i always suspected, but
never tested for myself: that the price
of the battery when weighed with the run time
in a given application means
'all batteries were created equal'
except in the case where high current
is required, such as in digital cameras.

This means the cheaper the battery, the more
cost effective, as you can simply replace
the battery with another cheap one and get
more run time then one expensive one.
Another interesting note is if you look
on the Energizer site and compare their
AA batteries, they spec the e^squared battery
to have less Ah capacity then the old
standard energizer! Yet you will have to
pay more for this one. Supposedly they can
put out higher current pulses like in
digital camera apps. Anyone try this?
Luckily, with low current LED draw we dont
have to worry about high currents.

--Al

No particular opinion here, only "food for thought", since NimH and rech. alkalines each do their own jobs pretty well.
I've seen recently 1200-1400 mAh NimH cells in surplus catalogs selling for as little as .75 ea
On the other hand, even on eBay, the Grandcell alk. rechargeables are going for about a dollar ea

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by videocal:
No particular opinion here, only "food for thought", since NimH and rech. alkalines each do their own jobs pretty well.
I've seen recently 1200-1400 mAh NimH cells in surplus catalogs selling for as little as .75 ea

On the other hand, even on eBay, the Grandcell alk. rechargeables are going for about a dollar ea

<HR></BLOCKQUOTE>


Oh those prices sound very good, do you think
these bargain rechargable batteries are
going to work decently?
I mean, since i havent ever tryed the NiMH
cells yet, the first set i get will
determine if i use them again. That is,
if they work decently then ill probably get
more in the future. Do you think it would
be a good idea to get these as a first set?

--Al

This is slightly off topic here, but here goes...

I keep a 2-D and a 3-D mag in my van, as well as a 4-AAA energizer, and the Brinkman LL-LED. I can put in brand-new batteries, and not touch the lights. After a few months, the mags just barely glow. I heard that heat can kill batteries. Since I live in Florida (cassette tapes have melted in my car), this seems reasonable. Do lithiums avoid this problem????

Also, I heard from an employee of a battery company that batteries ONLY leak if they are completely exhausted. This is why batteries never seem to leak in their packages, but almost-dead batteries will spill goo all over the drawer or device. I don't know exactly why, but my experience seems to confirm this.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by MrAl:

Oh those prices sound very good, do you think
these bargain rechargable batteries are
going to work decently?
I mean, since i havent ever tryed the NiMH
cells yet, the first set i get will
determine if i use them again. That is,
if they work decently then ill probably get
more in the future. Do you think it would
be a good idea to get these as a first set?

--Al<HR></BLOCKQUOTE>

The Nimhs (new, but at heavy discount) were Sanyo, Toshiba, Duracell Panasonic etc. and they have performed extremely well. I guess I like 'em because they can be "topped off" and used under pretty high drains with no problems.
Recommended sources are B.G. Micro, Hosfelt, Thomas Dist. Sunn, etc.

Imho, NimHs, coupled with pulse/smart charging, are the best bet for a lot of applications and they do allow me to go about doing other interesting things, without worrying about batteries or recharging anymore.
Example: 2-1800mAh AAs can be properly charged in 90min. or so

-How drastically things have changed in the last 5 years-from 500mA Ncds., memory effect and 12hr."dumb" charging!

Yes, lithiums are pretty durable. They work at hot and cold temps without much of an issue. They also have over 5 times the shelf life of alkaline batteries.