Re: [NTLK] a question about batteries

From: Peter H. Coffin (hellsop_at_ninehells.com)
Date: Thu Sep 30 2004 - 10:12:27 PDT


On Thu, Sep 30, 2004 at 10:21:03AM -0400, Scott Lewis wrote:
>
> On Sep 29, 2004, at 2:19 PM, Martin Joseph wrote:
>
> > 15 minutes ? What kind of batteries are these? Or are you saying you
> > have some special charger for NiMH batteries that can charge them in 15
> > minutes? Either way enquiring minds want to know...
>
> Again, I wish I knew what type of batteries they are! I can only
> presume they are NOT NiMH, since they Rayovac does not advertise them
> as NiMH. Rayovac's previous charger was a 1 hour charger, and was
> specifically designed to charge NiMH and NiCAD. This charger charges
> their "I-C3" batteries in 15 minutes, and all other NiMH and NiCADs
> overnight.

As you read at the URL below (but repeated here for those reading mail
on their Newts), they're NiMH cells with some internal monitoring bits
that track internal pressure, thus track the charge state faster than
temperature monitoring from outside the cell, and allowing much higher
charge currents. The cells charge in an hour in "normal" NiMH chargers
so I presume there's some kind of signalling the battery does to the
I-C3 charger to control the charge current, and it seems to happen on a
cell-by-cell basis as well.

> In my opinion, these batteries last as good as any 2000-2200 Mah
> batteries you would find in a local retail store (ie Radio Shack
> brand).

I'm guessing based on the product line, but they're likely to be about
1800 mAh cells.

> This is the real deal though - 15 minutes. They get a little hot, and
> Rayovac actually built a little fan into the charger to keep the
> temperature down.

They're shovelling in probably about 4x the amount of current... Heat's
not the enemy per se, heat's a cause of the real hazard of rupturing,
and these seem to be tracking the "rupturing" question more directly.

> I just went to their web site, and in fact they are a derivative of
> NiMH. Apparently I-C3 stands for "In-Cell Charge Control", you can read
> about it here: http://rayovac.com/products/recharge/15minutes/qa.shtml
>
> According to the site, they are in fact NiMH, and can be charged in any
> NiMH charger - but not in 15 minutes (obviously).

-- 
73. I will not agree to let the heroes go free if they win a rigged contest, 
    even though my advisors assure me it is impossible for them to win.
                --Peter Anspach's list of things to do as an Evil Overlord
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