On Fri, 27 May 2011 17:37:46 -0700, Jeff Liebermann wrote:

On Thu, 26 May 2011 12:51:48 -0500, Puddin' Man
wrote:


The + side measures 3 ohms.

Ok. There may be a diode inside the base. Try reversing the leads on
the ohms-guesser and see if it acts like a diode.

Measures infinite ohms when reversed.

It's a diode, with no series resistor. That presents a problem.
Without some form of current limiting, the voltage of the xformer will
need to be VERY carefully controlled to keep from overcharging the
battery. I will swear there's a resistor or charge controller
somewhere in the system, but I can't tell where from here.

I dunno where it would be ...

I'm 'fraid you'll have to elaborate on this last. And, what is "C" in
.1C?

Sorry. C is the current rating of the battery in ampere-hours. A
typical NiCd pack, full of AA cells will have a rating of about 750
ma-hr. NiMH would be around 1200 to 2200 ma-hr. The maximum charge
current of the charger should be about 0.1 times this value (i.e. 10%)
or 75ma for the NiCd pack.

Thanks.

Of course, make sure you don't have a shorted
battery pack.

So I gotta crack the battery pack open. And test each cell individually?
How?

You don't need to destroy the battery pack in order to test it.

Good! :-)

First,
just measure the terminal voltage of the battery pack after it's been
sitting around for a day without being charged. Even if totally
discharged, it should have at least 1.1 volts per cell or about 7.7VDC
across the terminals. A fully charged NiCd will have about 1.45VDC
per cell or about 10.2VDC across the terminals.

I measure just under 4vdc for the pack. Your opinion is
solicited.

Now, if you really want to test you battery packs, I have a West Mtn
Radio CBA-IIv1:
http://www.westmountainradio.com/product_info.php?products_id=cba3

Only $150-300. Lordy mercy!

I rambled thru my WW box again and found the following:

ATLINKS USA
Telephone power supply
Input: AC120V 60hz 4.4w
Output: DC 9v 200 mA
Class 2 transformer
UL etc

but when I measure, I get about 20vdc from my meter.
Any idea why the drastic difference from spec?

Thx,
P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."