battery question - nimh vs hybrid nimh

I took some standard nimhs (Lenmar Nomem 200mah) out of my charger, my
brother put them in his camera, and the camera immediately reported the
batteries were too low to run the camera.

Then I gave my brother my hybrid nimhs (Uniross Hybrio) from my cordless
mouse - he took 152 pictures on them with flash, and the camera still
reported the battery fully charged.

I took back the hybrid nimh batteries and tested them to see their charge
level - they had less charge than the batteries that the camera rejected
immediately! What is the explanation for this?

 

It depends a lot on how you are doing the testing and what
voltage the camera cut-off is set for. My own camera has to be
set for battery type but it's old enough not to have Hybrio as a
choice. The measurement is carried out, I believe, by measuring
the voltage under a load. The trouble with many testers is that
the meter shows Good...watch it...bad or something like that not
voltage but, unless you know the battery characteristics, it's
what most people want.

The same sort of thing happens for equipment like cordless mice
(mouses if you will My own Logitech mouse does not give much
time to start recharging before it dies completely. Fortunately,
the undocumented level can be changed.

 

I think my son has a similar problem with his cordless mouse. I also
suspect the test method, however, that doesn't explain why the op is
getting poor results with the regualr NiMH. I've owned 3 sets of NiMH
and am now using eneloops. One of those set (Rinpoche from Walmart)
never worked in the camera and when I eventually got a smart individual
cell charger I could see one or more cells took a very long time to shut
off and got hot in the meantime. However, they worked reasonably well in
a battery operated razor. Sometimes you can just pick up a bad set of
cells that maybe just can't hack the current drain.
Dave Cohen

 

I could just be dirty contacts on the battery or camera. Clean both
with alcohol and try your test again.

 

What is the different between nimh and hybrid nimh?

 

I would tend to think the dirty contact idea is the real answer.
However keep in mind that different battery types react differently under
different drain levels. The camera is only saying that the batteries in
question meet the minimum specs for that specific use, based on what the
recommended battery type would measure. Different battery types could
measure differently. Note that some battery types could damage the camera
if they are not of the type recommended by the camera manufacturer. Playing
with different types in an expensive camera can be ... well expensive.

 

A year or so ago sanyo marketed their 'enerloop' which, it was claimed,
removed the problem experienced with nimh batteries of losing charge over
time. 'hybrid' is rayovac's name for the same technology. There is nothing
'hybrid' about it - just a marketing name.

 

Your question can't really be answered definatively unless you
describe how you tested the charge levels as well as stating the
results that you got. People in the past have done this using
several different methods, some useful, others not very . . .

 

And a very poor choice of name at that. Eneloop doesn't exactly convey
much either but at least it seems to be unique (my dictionary doesn't
show it). But what the heck, they work great and I would expect this
type to eventually supersede normal NiMH's, particularly if they can up
the capacity a little.
Dave Cohen

 

The probably could, but I'd rather they didn't, as it seems to be
a tradeoff between low self-discharge and high capacity. From the
little I've read about Eneloop type NiMH batteries, they're not
really chemically different than standard NiMH cells. The
difference is due to mechanical construction, such as thicker, less
porous internal membranes that helps slow down unwanted chemical
reactions. I don't approve of some of the techniques used to
increase capacity. One is to slightly increase the diameter of the
NiMH AA cells. This makes them hard to insert and remove in some of
my non-camera devices, but it certainly allows the inclusion of more
NiMH "soup".

At first I suspected that the increased diameter might have been
due to stretching due to the heat from many charge cycles. But I
soon found that some brand new NiMH cells were oversized. I've
never found any alkaline battery brands that had abnormally large
diameters.

 

How did you test each battery? It's not trivial to test NiMH batteries
for remaining capacity. The capacity decreases as the battery ages, and
a large part of the capacity is used up at a relatively flat voltage.

See "http://www.thomasdistributing.com/zts-mini-mbt-battery-tester.htm"
for a battery tester that will give a reasonably good estimate of
capacity. Some chargers also will do a pulse load test, and some will do
capacity test by charging then discharging the battery and calculating
the mAH.

It's a good idea to check all your batteries for capacity so you match
up sets that are close in capacity. Use a charger like the Maha MH-C9000
or the La Crosse BC-900 to test the capacity of each cell.

As to the Lenmar, I think you may have a bad cell (or more than one). I
bought a bunch of those 2000 mAH Lenmar cells a while back because they
were very cheap, but they were not very good, and I had several bad cells.

Steve
http://batterydata.com