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?
Hint: Accelerated lifetime tests are usually done at elevated
temperatures and for short periods. They are then extrapolated back
to room temperatures and longer periods. The curves are well behaved
and apply to all chemistries after the initial self-discharge.
http://corrosion-doctors.org/Batteries/self-compare.htm
The 3rd generation Eneloop claims 70% after 5 years. How to recognize
which Eneloop generation:
1st gen - No crown icon
2nd gen - Crown icon near plus sign
3rd gen - Crown and metallic colored letters.
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. My undocumented wild guess(tm) is that the
break even point is at about 2 months. That's because the initial
(i.e. immediately after a full charge) for the ordinary NiMH battery
is about 2200ma-hr, while the Eneloop are about 1900ma-hr.
http://www.eneloop.info/fileadmin/EDITORS/ENELOOP/DATA_SHEETS/HR-3UTGA_data_sheet.pdf
http://budgetlightforum.com/node/7336
http://flashlightwiki.com/Eneloop
This weekend (ham radio field day), I took about 30 photos with a set
of no-name 2300ma-hr NiMh batteries when the charge indicator
appeared. The batteries were charged about 4 months ago. I switched
to a set of 1st generation Eneloop batteries, that I had charged about
7 months ago, and had previously shot about 100 photos. The charge
indicator showed 50%. However, after another 50 photos, the charge
indicator still showed 50% implying that there was plenty of capacity
left. Yep, Eneloop are good batteries for cameras.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558