I ask this question here because between everyone we have the sum of human
knowledge ............

I bought some nimh rechargeable batteries and a charger for my camera. They
are AA 1.5 v. size.

When I need to test batteries, I use a pretty good Craftsman tester. On
alkaline batteries, when new, they test up to 1.6 volts. I had some of
these nimh batteries on charge for a good while on an automatic charger.
The indicator light had gone out, indicating a full charge.

I wanted to see how much they read. They read from 1.42 to 1.45 volts. Is
this normal? Do they just last longer, but don't charge up as much? I know
they last a LOT longer in my GPS, and have saved me money already in
batteries. In my radios, the nimh runs circles around alkalines or nicd for
lasting.

Just curious.

Steve

SteveB wrote:
I ask this question here because between everyone we have the sum of human
knowledge ............

I bought some nimh rechargeable batteries and a charger for my camera. They
are AA 1.5 v. size.

When I need to test batteries, I use a pretty good Craftsman tester. On
alkaline batteries, when new, they test up to 1.6 volts. I had some of
these nimh batteries on charge for a good while on an automatic charger.
The indicator light had gone out, indicating a full charge.

I wanted to see how much they read. They read from 1.42 to 1.45 volts. Is
this normal? Do they just last longer, but don't charge up as much? I know
they last a LOT longer in my GPS, and have saved me money already in
batteries. In my radios, the nimh runs circles around alkalines or nicd for
lasting.

This is normal. NiMH and NiCd batteries are really 1.2 volts. They might be dimmer in a flashlight, but for high drain items like digital cameras, and apparently your GPS, they can and do last longer. Their capacity and voltage are lower but they last longer because they have a much lower internal resistance and are far more efficient than alkaline batteries for higher current loads.



Just curious.

Steve

On 10-Dec-05 1:23 AM, SteveB wrote:
I ask this question here because between everyone we have the sum of human
knowledge ............

I bought some nimh rechargeable batteries and a charger for my camera. They
are AA 1.5 v. size.

When I need to test batteries, I use a pretty good Craftsman tester. On
alkaline batteries, when new, they test up to 1.6 volts. I had some of
these nimh batteries on charge for a good while on an automatic charger.
The indicator light had gone out, indicating a full charge.

I wanted to see how much they read. They read from 1.42 to 1.45 volts. Is
this normal?

IIRC the nominal voltage for a AA NiMH is 1.2V so your figure was
probably obtained from a cell direct from the charger and off load.

Do they just last longer, but don't charge up as much? I know
they last a LOT longer in my GPS, and have saved me money already in
batteries. In my radios, the nimh runs circles around alkalines or nicd for
lasting.

NiMH batteries are better suited to high discharge applications (digital
cameras are a prime example) where they significantly out perform
alkalines. The discharge curve is also 'flatter' than NiCAD or alkaline
which means they provide max power for longer but then suddenly go
'flat'. NiMH batteries (like NiCADs) are prone to self discharging and a
fully charged battery will discharge while sitting even if it is not in
any equipment.
A very useful source for battery information can be found at the
following link.....

http://www.buchmann.ca/

HTH

--
Larry Green

"SteveB" wrote in message
news:Ouumf.1697$Ev.1648@fed1read06...
I ask this question here because between everyone we have the sum of human
knowledge ............

I bought some nimh rechargeable batteries and a charger for my camera.
They are AA 1.5 v. size.

When I need to test batteries, I use a pretty good Craftsman tester. On
alkaline batteries, when new, they test up to 1.6 volts. I had some of
these nimh batteries on charge for a good while on an automatic charger.
The indicator light had gone out, indicating a full charge.

I wanted to see how much they read. They read from 1.42 to 1.45 volts.
Is this normal? Do they just last longer, but don't charge up as much? I
know they last a LOT longer in my GPS, and have saved me money already in
batteries. In my radios, the nimh runs circles around alkalines or nicd
for lasting.

Just curious.

Steve

(Should read: Just, Curious Steve...sounds better)
Normal! I bought 4 AA and a charger from WalleyWorld for $9.99! Beat that!

SteveB wrote:
I ask this question here because between everyone we have the sum of human
knowledge ............

I bought some nimh rechargeable batteries and a charger for my camera. They
are AA 1.5 v. size.

When I need to test batteries, I use a pretty good Craftsman tester. On
alkaline batteries, when new, they test up to 1.6 volts. I had some of
these nimh batteries on charge for a good while on an automatic charger.
The indicator light had gone out, indicating a full charge.

I wanted to see how much they read. They read from 1.42 to 1.45 volts. Is
this normal? Do they just last longer, but don't charge up as much? I know
they last a LOT longer in my GPS, and have saved me money already in
batteries. In my radios, the nimh runs circles around alkalines or nicd for
lasting.

Just curious.

Steve



It's impressive to see the energy storage improvement in Ni-MH
batteries. A few years ago the best AA Ni-MH batteries I could find
stored 1500 maH, now they're up to 2500 maH.

Duracell has a pretty good tech section pdf about Ni-MH batteries at:

http://www.duracell.com/oem/Pdf/others/TECHBULL.pdf

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

On 10 Dec 2005 09:01:00 +0100, Larry Green
wrote:


...

NiMH batteries are better suited to high discharge applications (digital
cameras are a prime example) where they significantly out perform
alkalines. The discharge curve is also 'flatter' than NiCAD or alkaline
which means they provide max power for longer but then suddenly go
'flat'. NiMH batteries (like NiCADs) are prone to self discharging and a
fully charged battery will discharge while sitting even if it is not in
any equipment.
A very useful source for battery information can be found at the
following link.....

http://www.buchmann.ca/

HTH


You answered one question that I just happened to want to know
when your post showed up, but you missed the other one.
What's the discharge curve for a lithium ion battery? Is it
flat also? I didn't find the answer on the website you mentioned.

Wayne D.