Re: Rechargeable Alkalines

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"B Fuhrmann" <b-fuhrmann-usenet@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:131daaa42gpe438@xxxxxxxxxxxxxxxxxxxxx
> "Robert Green"  wrote ...
> >A short while back we had some discussions about rechargeable alkalines.
> > Since it's been at least 10 years that I last tried them, I thought I
> > would
> > give the "Juice" product sold on Ebay a try in my Nikon Coolpix Battery
> > Hog
> > 950.  The problem with the camera is that just by sitting a week or so,
> > fully charged NEW NiMH cells apparently drop in voltage enough to cause
> > the
> > camera's LOBATT warning to appear, shutting the camera off.  Testing
> > reveals
> > the batteries are still nearly fully charged, but it seems that only HOT
> > batteries fresh from the charger can be depended upon to work.
>
> I think that it was a function of equipment being designed for the higher
> voltage alkaline cells.  I know that there is no "memory" effect with NiMH
> cells but there is some sort of problem that can cause them to not
recharge
> fully.  I have several sets that have some problem that causes them to
short
> cycle in the GPS and other sets that can sit for a couple weeks and run
the
> full time.
> I have considered doing some sort of battery tester that I can run on
cells
> to match their capacity.  Just don't have the free time.  It would include
> an appropriate load with a timer and voltage sensor so that I can do a
> resistive load that is roughly the right current for the GPS and measure
how
> long till the cell hits 1/2 of the GPS turn off voltage.

I hooked my RatShack multimeter to an old Dell laptop and with the
resolution set to 240 seconds I get a pretty good readout.  I use a
flashlight bulb in a small socket and read the voltage across the bulb
terminals.  I find I don't need it as much as I used to because the newest
chargers have circuitry that detects bad cells pretty reliably (and doesn't
have to put them through a discharge cycle to do it).  If the charger slot
LED flashes rapidly after insertion, it's not a battery to depend on nor
will it charge.  Often, they will still power a little portable fan for
quite some time;  just not voltage sensitive electronics.  So far, the best
performers out of many different brands has been Kodak.  Go figure.  They've
held almost a 1/2 charge for over six months!

> > I solved the problem for the even more low-voltage sensitive CoolPix
2100
> > with rechargeable LIon's.  NiMH cells would register low battery in just
a
> > few days of sitting idle.  The LIon cells give me the best of both
worlds.
> > The camera will still run from common AA's if I am stuck in the field
> > without a recharger, but performs *very* nicely now, weeks after a LIon
> > pack
> > is installed.
>
> Are using CRV3 type batteries?
> www.eastcoastphoto.com/nav/itempage.asp?itemid=6055&trng=fgle
>
> If not, what do you use?

I bought something from Ebay for $13 total ($6 for the charger and battery,
7$ for shipping!) that was a private sale - someone had bought it but then
lost the camera.  The standard battery merchants that haunt Ebay were about
double that price.  It came in one of those armored plastic clam shells so I
am pretty sure it was new because I had to band-saw it out of there.

The battery is labeled "Dual Power" and is made in Taiwan.  The charger came
with a car cord and a transformer.  I got over 100 average distance flash
pictures using it.  The nicest part is that after two months of sitting on
the shelf, the battery meter still says full.  I get at least as much power
out of them as I do from freshly charged NiMH cells in addition to excellent
shelf life.  I wish more things were designed to take both CRV3's and normal
AA cells.   I'm very happy with them in the Coolpix 2100.  It was a real
bear to keep stoked with NiMH cells.

FWIW, I tried recharging a non-rechargeable LIon and it wouldn't bite.  It
raised the cells to 3v pretty quickly, and they powered an LED for a little
bit, but it was clear that it was designed to charge only the rechargeable
kind.  The camera never powered up with them.   I did use a blast shield
during the test just in case.

> The terminals seem to be recessed inside the battery (makes sense
> considering what shorting can do to them.

I've seen news cameraman begin to smoke as one of their belt pack batteries
shorted. There's an insertion bump that acts as a key to prevent putting the
CRV3 in the wrong way.  There are two very stiff springs in the camera body
to contact either type of battery.
Here's the blurb from the ad:

SEALED IN BLISTER PACK
FULL 3 YEAR USA FACTORY WARRANTY
MADE BY DIGITAL CONCEPTS
* * * FITS FOLLOW MODELS * * *
CR-V3 DL-CRV3B K-CRV3 GES-LC-CRV3
CRV3 EL-CRV3BP LB-01E CRV3-A/1B
Quick Charges in 90 Minutes
Microprocessor To Control Charging
LED Charging Indicator
Contents
One 90 Minutes Quick Charger
One Rechargeable Lithium-Ion Battery CR-V3
One AC Adaptor ( For use in your Home )
One DC Adaptor ( For use in your Car )

--
Bobby G.