[TriLUG] IC3 Misinformation (was batteries in laptops thread)
jbrigman at nc.rr.com
Mon Jun 27 01:50:05 EDT 2005
Dudes, would you please read the manual that came with the IC3 charger?
- don't mix IC3 batteries with NiMH batteries,
- Leave NiMH batteries in overnight
(ie: they don't charge in 15 minutes)
IC3 batteries are not typical NiMH batteries, which are charged at far
lower rates over timespans of 16 hours or so. As Tanner hinted, this is
because IC3 batteries have a built-in charge regulator (IC3 = In-Circuit
Charge Control). The NiMH units will charge in the IC3 charger, but not
in 15 minutes. You're not getting a full charge on your NiMH batteries
if you think you can leave them in for 15 minutes and you're done.
For the first 300-odd charges, the IC3 batteries ought to reach 70-85%
charge in 15 mins. As you progress toward the end of the 1000-charge
lifecycle of these batteries, you're going to start seeing significant
increases in generated heat and completed charge rates of 50-55% or
worse. I expect that charger is going to fail toward the end of the
battery lifetime. (Exactly what the vendor wants to happen.) As a point
of comparison, I still own and use all the chargers I've ever purchased,
and I have some NiMH batteries I've used for over 5 years that I've
bought from well-known battery suppliers at the major hamfests.
The pro camera dudes are debating the IC3 batteries fairly energetically
primarily because of the hot cells that come out of the charger:
Most folks are getting great results from the IC3 batteries and
chargers, and I'm glad for that, I hate to see anyone get ripped off.
But they don't yet seem to know that the charger will eventually fail as
the batteries become hotter and hotter, the chemical breakdown due to
heat dropping their internal resistance increases over time, making it
harder for the ICCC to control the delivered current. The charger will
get hotter with the increased load and most likely fail as the batteries
I can assure anyone reading this list that it is completely true that
NiMH batteries are more sensitive to heat than NiCD batteries. (Is it
possible to be anything but "completely true"?) In any case, excessive
or prolonged heat is going to shorten the life of all but the molten
sulfur or fuel cell technologies.
On Mon, 2005-06-27 at 00:09 -0400, Tanner Lovelace wrote:
> On 6/24/05, Pat Regan <thehead at patshead.com> wrote:
> > James Brigman wrote:
> > > Aaron, you are correct: charge rates for NiMH differ from NiCD's, the
> > > NiMH are more sensitive to heat, so the charge rates are typically
> > > slower than for the NiCD's: no such thing as a fast charge for NiMH.
> > >
> > I am not sure if that is completely true. A friend of mine has a little
> > wall-wart AA/AAA NiMH 15 minute charger that seems to work well. Much
> > faster than my big, clunky 3 hour charger :)
> I've used the 15 minute rechargable AAs for almost a year now and I
> can testify that they work *extremely* well. I believe the secret in
> getting them to charge so quickly is that the charger itself has a built-in
> fan that is used to keep the batteries from getting too hot and it's an
> extremely smart charger. It's also possible the batteries themselves
> have other circuitry in them to help with this too, I don't know.
> Whatever the case, they work great and they're decent batteries
> too (2000 mili-amp-hours).
> They can be found as either Rayovac or Radio Shack brand and they're
> called IC3 (one of those letters is a super or subscript). I *highly*
> recommend them. After using them, you'll never want to go back
> to a 3 hour charger.
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