10 November 2015
as shown in Figure D.
The difference in your 40 degree storage temperature
and my 0 degrees could mean you are getting around 1/3
of the shelf life I am getting (I am avoiding presenting the
I have grandkids and we need batteries available
constantly, so shelf life is a must for me. I can warm the
batteries up very quickly by placing them close to my body
if the TV remote or toy batteries go out.
As far as expiration dates printed on the batteries, I
don't pay them too much attention. I have had batteries
go "bad" that were still in the package, way before the
expiration date. I have also had batteries still be good after
the expiration date.
One special warning: Be sure to check batteries often
when they are installed in your devices. I recently tried to
use my programmable calculator (read VERY expensive) to
sadly find the batteries were dead. The real problem was
there was a clear skin-burning liquid inside the battery
compartment which I removed post haste.
If you have ever tried to clean the battery corrosion
products from a device, you know what I mean. It is a lot
easier to check the battery condition periodically than to
clean up the mess.
Re: July 2015 "GFI Breakers"
#1 I would suggest retesting the problem outlet except
for the fact that the hair dryer worked, and at 1,200 watts
it would draw 10 amps; meaning that the other wiring
would get hot if it had, say, two ohms because it would
use 20 watts, and thus get as hot as a small light bulb if
left on for three to five minutes. Measuring the voltage at
the remote outlet is a good idea, but my feeling is that this
would be of no help because the two computer power
supplies did not like a GFCI in the past.
What the computer power supplies may have had in
common with the radio is a switching power supply. This
seems like a bad idea at first, but could be a good thing.
My eight year old CD player/radio picks up noise from my
overhead LED light; this noise may be coming through an
analog power supply. A properly designed switching supply
would have very good filtering of 0 to 1 MHz so as not to
pass anything to the audio section. Therefore, I would look
for a difference in RF properties between outlets.
I would set up a scope to read the voltage at a normal
outlet and plug the radio in. If the unit has a switching
supply, some waveform may show up. Then, do the same
on the protected outlet. You may not see the same wave
form. If so, you have proven that the switching power
supply does not like the GFCI due to some factor such as
series inductance. The radio may also have some tricky
defect in it that only shows up when using the GFCI, so as
a last resort, buy another radio of the same kind and
inspect its circuits to see what clues they offer.
#2. A few points regarding the GFI Breakers
1) Mr. Edwards said that he was “changing plugs,”
but I suspect he meant that he was replacing the outlets.
2) Between the late ‘60s and late ‘70s, some homes
were wired using aluminum wire. This might be
contributing to the problem that Mr. Edwards described,
■ FIGURE 2 from July 15 column.
A special note of
appreciation ... I
wrote the first part of
this month's column
six days after having a
triple coronary artery
bypass surgery. I
would like to thank
God, the medical
friends, and the Nuts
& Volts community
for the support I have
received during this
■ FIGURE D.