Handhelds and alkaline batteries

"Chris W" wrote in message
...
Jim Weir wrote:

Alkalines have a problem when you get to the power levels we are talking
about
for transmit. They last a mercifully short time in most HTs. We've
found that
popping for the NiMH cells is far better from a time and life point of
view.

For an emergency only radio, NiMH are about the worst battery to use.
They have a
self discharge rate of 10% per day. The Lithium Ions are the next best
then
NiCd. Of course the self discharge rate of alkaline batteries are a lot
better
than any of the rechargeable but they don't do well with high current
loads that
some electronic equipment need. The non rechargeable Lithium batteries
are the
best in that regard, they last a long time, lowest self discharge rate of
any
battery and they can take the high current loads, the only down side is
they are
expensive, especially if you go to the corner drug store where they some
times will
charge $8 or more each, if you look around on the internet you can get
them for
less than $2 each. Of course that doesn't do much good if your radio
doesn't have
a pack that will take the CR123 lithium batteries.


--
Chris Woodhouse
Oklahoma City

"They that can give up essential liberty
to obtain a little temporary safety

Chris, can you quote a source on the 10% discharge per day on the NiMH? I
have not found that to be the case.
--
---Jim in NC---

Morgans wrote:

Chris, can you quote a source on the 10% discharge per day on the NiMH? I
have not found that to be the case.
--
---Jim in NC---

http://www.allegromicro.com/techpub2/cadex/index32.htm

apperently I didn't remember the details exactly right but the fact that NiMH
have a very bad self discharge rate is true. In fact rechargable batteries as a
group have a self discharge rate that is a lot worse than most non rechargable
batteries.

--
Chris Woodhouse
Oklahoma City

"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety."
-- Benjamin Franklin, 1759 Historical Review of Pennsylvania

Chris W wrote in message ...
Morgans wrote:

Chris, can you quote a source on the 10% discharge per day on the NiMH? I
have not found that to be the case.
--
---Jim in NC---

http://www.allegromicro.com/techpub2/cadex/index32.htm

apperently I didn't remember the details exactly right but the fact that NiMH
have a very bad self discharge rate is true. In fact rechargable batteries as a
group have a self discharge rate that is a lot worse than most non rechargable
batteries.

From the link you supplied:

"Self-discharge: Both NiMH and NiCd are affected by reasonably high
self-discharge . The NiCd loses about 10% of its capacity within the
first 24 hours, after which the self-discharge settles to about 10%
per month. The self-discharge of the NiMH is one-and-a-half to two
times higher than that of the NiCd. Selecting hydride materials that
improve hydrogen bonding to reduce self-discharge typically also
decrease the battery capacity."

So it's more like 10% for the FIRST day, then 10% per MONTH
thereafter.

SM

Squirrel wrote:

http://www.allegromicro.com/techpub2/cadex/index32.htm

From the link you supplied:

"Self-discharge: Both NiMH and NiCd are affected by reasonably high
self-discharge . The NiCd loses about 10% of its capacity within the
first 24 hours, after which the self-discharge settles to about 10%
per month. The self-discharge of the NiMH is one-and-a-half to two
times higher than that of the NiCd. Selecting hydride materials that
improve hydrogen bonding to reduce self-discharge typically also
decrease the battery capacity."

So it's more like 10% for the FIRST day, then 10% per MONTH
thereafter.

For NiCd that is right, but is also says up there in the section you quote that NiMH
has 1.5 to 2 times higher self-discharge than NiCd so 15-20% the first 24 hours and
15-20% per Month after that.


--
Chris Woodhouse

"They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety."
-- Benjamin Franklin, 1759 Historical Review of Pennsylvania