Ali,
although I have few Rayvac Hybrid cells (AAA's), I have not really tested
them carefully. It
is also quite possible they are not actually made by Rayovac. Like many battery
vendors, their
website does not have detailed technical specifications for comparisons.
In general the other hybrids, compared with Eneloop, seem to self discharge
a bit faster and
have a higher impedance, so not quite as good for high rate applications like
flash. It makes a
difference to a flash like T32 which stops charging if voltage drops much below
~1.1V/cell under
load. For example the "Acculoop" brand, generic hybrid cells (who might supply
a company like
Rayovac), have a impedance 60% higher than the eneloop and a maximum rated
current of 4A. Eneloops
comfortably go to higher current. Claimed Self discharge for the generic
"Acculoop" brand Hybrids
is about 25% pa nominal, compared with Eneloop at 15%. Titanium "Enduro" and
NAB/Ross "Hybrios"
seem to be similar hybrid cells to the "Acculoop" generics.
The eneloops seem to self discharge 7-9% in first month and then much slower
after that. To get to
claimed 15% pa they would need to do less than 1% pm after that. They seem to
discharge at a bit
higher rate than that, but I don't have time to test! Normal NimH drop 20-40%
in first month and
~1%/ day thereafter, but do slow down after 2 to 3months, but by then capacity
is pretty low.
Sanyo actually claims a self discharge slower than that for it's regular NiMh
cells, so it seems
there is big spread depending on vendor. (Sanyo claim 25% loss in capacity at
3months for its
regular NiMh). Measured Eneloop self discharge by other peole on web , gives
about 13% at
6months, a little worse than sanyo claims (10%) but pretty good compared with
NiMh. Somebody on
the web posted a test on Hybrios and found 15% loss in the first month. Likely
will slow a lot
over time like eneloops.
The impedance specs for the AA Eneloops is 25mOhms/cell. I measured it at DC
(a tougher test) and
got a value of about 24mOhms (at 20% discahrged from full), so a bit better
than claimed but
pretty close. For Engineers a good cell model uses an o/c voltage 1.27V, with
24mOhms impedance.
This model fits the dc test data pretty well over a very wide range of currents
at the 20% from
full discharge point where discharge curve is flattest.
The "eneloop" cycle life claim is 1000cycles vs 500 for the "Hybrios". These
sort of comparisons
depend a bit on how you spec the test and how deeply you discharge each cyle,
so hard to really
know.
Tim Hughes
--- Ali Shah <alizookoman@xxxxxxxxx> wrote:
>
> Any thoughts on the RayoVac Hybrids. I have had pretty
> good luck with these.
>
> http://www.rayovac.com/recharge/hybrid_technology.shtml
>
>
>
>
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