View Single Post
  #21   Report Post  
Posted to sci.electronics.repair
isw isw is offline
external usenet poster
 
Posts: 320
Default Atomic CLock with pure 120v ac?

In article ,
Jeff Liebermann wrote:

On Sun, 24 Jun 2012 21:48:04 -0700, isw wrote:

In article ,
Jeff Liebermann wrote:

On Sun, 24 Jun 2012 11:28:23 -0500, Jim Yanik
wrote:

Jeff Liebermann wrote in
:

If you use NiMH batteries, which tend to self-discharge at a rather
high
rate,

the 2300 mAH AA Everready NiMH(not pre-charged) that I bought at WalMart
seem to not have a high discharge rate. I use them for my LED bicycle
lighting system. the NiMH cells came with a "smart charger".
I charge them maybe once a month.

With typical NiMH, I loose about 20% of charge in the first 24 hrs,
and then about 1% per day. I've confirmed this with my own tinkering.
After about 3 months, I typically have a half dead battery.


Try the Sanyo Eneloop cells; they claim about 85% after a year of
storage, and my experience using them in my camera confirms that.
Isaac


You didn't use your camera for a year?


Of course not; I walk a lot and use it all the time. When the cells in
the camera go dead, I replace them with the charged spares I always
carry. With "standard" cells, the spares were often near end-of-life
when I installed them. With the Eneloops (even with their lower mA-Hr
rating), I get several months of use even after carrying them around for
some months.


--snip--

I have a set of Eneloop and they are better than ordinary NiMH for
self discharge. However, when I counted how many pictures the camera
(Canon S5-IS) would take before the charge indicator began to
complain, I found that in the short term (about 2 weeks), the ordinary
NiMH batteries took more pictures. In the long run, the Eneloop
batteries did better.


Which is completely consistent with the fact the Eneloops gain that
lower leakage by using a thicker membrane between the electrodes --
which naturally reduces the mA-Hr capacity.

All I wanted was to not run out of battery while on a several-hour walk,
and then find that the "spares" were empty too. The Eneloops solved that
problem completely.

Isaac