I have three "power-off" lights that are dead because the batteries have
died. They take two AA batteries which I want to replace. Which type
would be the best - Lithium, Nickel-Cadmium, or Nickel Metal Hydride?
They would be plugged in and constantly charging until the power goes
off.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')

"---MIKE---" wrote in message
...
I have three "power-off" lights that are dead because the batteries have
died. They take two AA batteries which I want to replace. Which type
would be the best - Lithium, Nickel-Cadmium, or Nickel Metal Hydride?
They would be plugged in and constantly charging until the power goes
off.

--------------------------------------------------------------

The type of battery depends on what the charger is designed to charge. You
cannot just stick any battery into it and expect it to work -- especially
lithium, as they can catch fire if charged wrongly. Each type of battery has
a different working and charging voltage requirement. Replace the batteries
with the same type the lights came with.

My experience is that Ni-Cd's are virtually worthless (don't hold enough
charge). I have no experience with lithium ones. I'd recommend the NiMH's

HTH,

EJ in NJ
---MIKE--- wrote:
I have three "power-off" lights that are dead because the batteries have
died. They take two AA batteries which I want to replace. Which type
would be the best - Lithium, Nickel-Cadmium, or Nickel Metal Hydride?
They would be plugged in and constantly charging until the power goes
off.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')

On Mon, 15 Dec 2008 13:26:35 -0500, Ernie Willson wrote:

My experience is that Ni-Cd's are virtually worthless (don't hold enough
charge). I have no experience with lithium ones. I'd recommend the NiMH's


Even if the charger is not designed for NiMH'S? Each type has its own
charging requirements. A few chargers will charge multiple types, however,
it is highly unlikely the charger for these special lights will accept
multiple types of batteries. Putting the wrong type in will likely cause a
fire.

HTH,

EJ in NJ
---MIKE--- wrote:
I have three "power-off" lights that are dead because the batteries have
died. They take two AA batteries which I want to replace. Which type
would be the best - Lithium, Nickel-Cadmium, or Nickel Metal Hydride?
They would be plugged in and constantly charging until the power goes
off.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')

---MIKE--- wrote:
I have three "power-off" lights that are dead because the batteries have
died. They take two AA batteries which I want to replace. Which type
would be the best - Lithium, Nickel-Cadmium, or Nickel Metal Hydride?
They would be plugged in and constantly charging until the power goes
off.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')



Either NiCD or NiMH will be fine, since the things are always plugged
in, get the highest capacity cells you can find. Charge time and self
discharge rate are not really important. Any reputable brand should be fine.

Ernie Willson wrote:
My experience is that Ni-Cd's are virtually worthless (don't hold enough
charge). I have no experience with lithium ones. I'd recommend the NiMH's

HTH,


Lithium AAs are disposable, never attempt to charge one. Lithium
rechargeable cells are completely different electrically from NiCD and
NiMH, the latter two being virtually identical. Li cells are more than
double the voltage of the other chemistries, and require intelligent
charging circuits to avoid damage or fire.

Michael Dobony wrote:
On Mon, 15 Dec 2008 13:26:35 -0500, Ernie Willson wrote:

My experience is that Ni-Cd's are virtually worthless (don't hold enough
charge). I have no experience with lithium ones. I'd recommend the NiMH's


Even if the charger is not designed for NiMH'S? Each type has its own
charging requirements. A few chargers will charge multiple types, however,
it is highly unlikely the charger for these special lights will accept
multiple types of batteries. Putting the wrong type in will likely cause a
fire.

HTH,



These lights use a simple "dumb charger", that is the charge current is
limited by a resistor. NiMH and NiCD are close enough electrically that
they are interchangeable in most situations. They will undoubtedly
withstand a higher charge rate than the light provides, but that isn't
an issue. Batteries with a higher mAh rating will take correspondingly
longer to charge, but with something that is plugged in all the time
that isn't really an issue.

It will not cause a fire.

Michael Dobony wrote:
On Mon, 15 Dec 2008 13:26:35 -0500, Ernie Willson wrote:

My experience is that Ni-Cd's are virtually worthless (don't hold enough
charge). I have no experience with lithium ones. I'd recommend the NiMH's


Even if the charger is not designed for NiMH'S? Each type has its own
charging requirements. A few chargers will charge multiple types, however,
it is highly unlikely the charger for these special lights will accept
multiple types of batteries. Putting the wrong type in will likely cause a
fire.

HTH,



These lights use a simple "dumb charger", that is the charge current is
limited by a resistor. NiMH and NiCD are close enough electrically that
they are interchangeable in most situations. They will undoubtedly
withstand a higher charge rate than the light provides, but that isn't
an issue. Batteries with a higher mAh rating will take correspondingly
longer to charge, but with something that is plugged in all the time
that won't matter.

It will not cause a fire.

Ernie Willson wrote in
:

My experience is that Ni-Cd's are virtually worthless (don't hold enough
charge). I have no experience with lithium ones. I'd recommend the NiMH's

HTH,

EJ in NJ
---MIKE--- wrote:
I have three "power-off" lights that are dead because the batteries have
died. They take two AA batteries which I want to replace. Which type
would be the best - Lithium, Nickel-Cadmium, or Nickel Metal Hydride?
They would be plugged in and constantly charging until the power goes
off.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')



if you examine Digi-Key's catalog,there are NiCd cells specifically made
for continous charging.

NiMHs require monitored charging.

--
Jim Yanik
jyanik
at
kua.net

Jim Yanik wrote:
Ernie Willson wrote in
:

My experience is that Ni-Cd's are virtually worthless (don't hold enough
charge). I have no experience with lithium ones. I'd recommend the NiMH's

HTH,

EJ in NJ
---MIKE--- wrote:
I have three "power-off" lights that are dead because the batteries have
died. They take two AA batteries which I want to replace. Which type
would be the best - Lithium, Nickel-Cadmium, or Nickel Metal Hydride?
They would be plugged in and constantly charging until the power goes
off.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')


if you examine Digi-Key's catalog,there are NiCd cells specifically made
for continous charging.

NiMHs require monitored charging.



Monitored charging is better for any battery, but not required. My cheap
cordless phones all continuously charge the batteries, and they came
with NiMH AAAs. The key is to charge at a low enough current, if you
fast charge either continuously they will vent and fail early, but a
gentle trickle charge is fine. These cheap emergency lights don't come
with anything special, they come with the cheapest Chinese NiCD cells
available and virtually anything you find on the shelves will be an
improvement.

"---MIKE---" wrote in message
...
I have three "power-off" lights that are dead because the batteries have
died. They take two AA batteries which I want to replace. Which type
would be the best - Lithium, Nickel-Cadmium, or Nickel Metal Hydride?
They would be plugged in and constantly charging until the power goes
off.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')

RTFM and follow. Really. My first suggestion would be NiMH, as I have good
luck with them on my cameras and they save a lot on disposable alkalines.
But each, alkaline, NiCd, and NiMH have different operating characteristics
related to slow draws, the curve when they pass a certain use point, and
just things individual to each. I'm sure that the directions may clearly
state that you could use any kind, or specifically if there is some type you
should NOT use. I'd trust the manual more than anyone here.

Even me.

Especially me.

Steve

"James Sweet" wrote in message
...
Ernie Willson wrote:
My experience is that Ni-Cd's are virtually worthless (don't hold enough
charge). I have no experience with lithium ones. I'd recommend the NiMH's

HTH,


Lithium AAs are disposable, never attempt to charge one. Lithium
rechargeable cells are completely different electrically from NiCD and
NiMH, the latter two being virtually identical. Li cells are more than
double the voltage of the other chemistries, and require intelligent
charging circuits to avoid damage or fire.

Huh? NiCd and NiMH identical?

I don't think so, Tim.

Steve

No one has mentioned the memory effect of NiCd batteries. They should be
pretty well discharged before recharging because if you don't, they develop
a memory, and will not fully charge. NiMH do not, and you can charge them
even if you have only used them a little. It is better to discharge them
more to get a better recharge on them, but they do not have nearly the
memory effect of a NiCd.

James, you need to have your facts straight before stating things as Gospel.
Charge time not important? BWAHAAAAAAAAAAAA! That's rich.

Steve




On the contrary, you should do a bit more research, or maybe just read
my post more closely, as my statement of charge time not being important
reflects the specific condition of trickle or float charging. This isn't
really the best forum for this though, might wanna pop on over to one of
the EE groups, or candlepower forums, lots of discussion with a lot of
very knowledgeable people, both professional engineers and
hobbyists/enthusiasts.

Much debate has raged over the years on the topic of NiCD memory
effects, and to this day it remains controversial as to whether the
memory effect exists. My own experimentation suggests that the perceived
memory effect is due to poor quality chargers that severely overcharge
cells in the specified time unless they are discharged first, leading to
a dramatic reduction in lifespan. With any charger, there is a trade off
of charge time vs cell life and people like things to be fast. Most
inexpensive chargers have no onboard intelligence, they are simply a
constant current source and rely on the user to manually terminate
charging. If you want to charge a battery in a short amount of time with
one of those, you had better discharge it first so you know where you
start out, and then charge for a specific amount of time to prevent
overcharge. Better chargers are timer controlled and will charge at a
constant current of a few hundred mA in order to charge the batteries
relatively quickly, then revert to a 5-10mA trickle charge to maintain
them at a fully charged state, these will also overcharge if the
batteries are partially charged when you start out. The best chargers
are microprocessor controlled and monitor one of two things, cell
voltage vs time, or cell temperature rise to detect a fully charged
state and drop to a low current trickle charge. They are nice because
they are capable of individually charging multiple cells to full
capacity rather than charging groups in series and assuming all started
out the same.

Cheap items such as the emergency lights in question have very simple
chargers, they are a constant current source with no feedback, they
charge at a very low current which is essentially a trickle charge and
they do so constantly. The trade off here is long charge time, usually
close to 24 hours, but that doesn't matter since power outages usually
have more than that much time between them, as well as a somewhat
shorter cell life, given the resulting low cost of the item, this is
deemed acceptable. On a related note, years ago I got tired of the
backup battery in my digital clocks always being dead whenever I needed
it so I did a simple modification and installed a 1K resistor across the
isolating diode for the backup battery resulting in the power supply in
the clock providing a steady 3-5mA of current to a NiCD "9V" (really
7.2V) battery. This has been working great, and more than 6 years later
the original batteries in the four clocks I modified are still working
great despite being trickle charged steadily for those years.

In a nutshell, at high enough current level to charge a battery quickly,
180-500mA or more being typical, charge time is very important and
once the cell reaches full charge that energy will go into heating the
cell rather than the chemical reaction that stores energy. If you keep
that up, the electrolyte will vent and permanent damage will occur. On
the other hand, if you charge a cell at a low current of say 5-10mA, you
can charge it indefinitely without damage.

I stand by my claims that NiMH and NiCD are virtually identical from an
electrical standpoint and the differences only become important when
you're trying to charge them quickly or power loads that draw a very
high current. NiMH cells have a higher capacity generally speaking,
while NiCD cells have a lower internal resistance and are thus able to
dump that charge more rapidly. They both have a nominal cell voltage of
1.2V, they both have a recommended standard charge current of C/10,
where C is the mAh rating of the cell, and they both need to be charged
by a current limited source with an OCV higher than the nominal cell
voltage, and both can be trickle or float charged indefinitely at C/100
or so. This is based on my education, research, and years of personal
experience. If you insist that this is incorrect, please cite sources.

"James Sweet" wrote in message
...
---MIKE--- wrote:
I have three "power-off" lights that are dead because the batteries have
died. They take two AA batteries which I want to replace. Which type
would be the best - Lithium, Nickel-Cadmium, or Nickel Metal Hydride?
They would be plugged in and constantly charging until the power goes
off.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')



Either NiCD or NiMH will be fine, since the things are always plugged in,
get the highest capacity cells you can find. Charge time and self
discharge rate are not really important. Any reputable brand should be
fine.

No one has mentioned the memory effect of NiCd batteries. They should be
pretty well discharged before recharging because if you don't, they develop
a memory, and will not fully charge. NiMH do not, and you can charge them
even if you have only used them a little. It is better to discharge them
more to get a better recharge on them, but they do not have nearly the
memory effect of a NiCd.

James, you need to have your facts straight before stating things as Gospel.
Charge time not important? BWAHAAAAAAAAAAAA! That's rich.

Steve

SteveB wrote:
"---MIKE---" wrote in message
...
I have three "power-off" lights that are dead because the batteries have
died. They take two AA batteries which I want to replace. Which type
would be the best - Lithium, Nickel-Cadmium, or Nickel Metal Hydride?
They would be plugged in and constantly charging until the power goes
off.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')

You are betting your life and the lives of others on these lights
functioning. Don't accept any half baked ideas you might get here. Read
and follow the manual.

In my life, there has been many an item that specifically said what battery
to use and which not to use. I have ignored or just not read these
statements. They weren't things, though, that were life-saving devices, so
my poor reading skills didn't make a very big difference.

This can make the difference in life and death. Be sure.

PERIOD.

Steve




Talk about overly dramatic. These aren't built in emergency lighting in
a commercial building, but rather cheap plug in power outage lights that
you can buy in drugstores. They are not lifesaving devices any more so
than a dollar store flashlight tucked in the nightstand. Manual? They
might have had some instructions for use on the back of the package, if
you're lucky, but none of mine ever said anything about the battery, it
wasn't even meant to be user replaceable and weren't even name brand,
just cheap generic AA NiCDs. I've had a couple similar lights, they
seemed like a good idea and were handy at times, but hardly fail safe,
and half the time they turned out to be broken by the time they were
needed. Now I just keep flashlights stashed in convenient locations.

On Mon, 15 Dec 2008 10:50:48 -0800, James Sweet wrote:

Michael Dobony wrote:
On Mon, 15 Dec 2008 13:26:35 -0500, Ernie Willson wrote:

My experience is that Ni-Cd's are virtually worthless (don't hold enough
charge). I have no experience with lithium ones. I'd recommend the NiMH's


Even if the charger is not designed for NiMH'S? Each type has its own
charging requirements. A few chargers will charge multiple types, however,
it is highly unlikely the charger for these special lights will accept
multiple types of batteries. Putting the wrong type in will likely cause a
fire.

HTH,



These lights use a simple "dumb charger", that is the charge current is
limited by a resistor. NiMH and NiCD are close enough electrically that
they are interchangeable in most situations. They will undoubtedly
withstand a higher charge rate than the light provides, but that isn't
an issue. Batteries with a higher mAh rating will take correspondingly
longer to charge, but with something that is plugged in all the time
that isn't really an issue.

It will not cause a fire.

Okay, will you pay for damages if it causes a fire? When you personally
sign responsibility for liability for any damages incurred, then I'd listen
to you, maybe.

Michael Dobony wrote:
On Mon, 15 Dec 2008 10:50:48 -0800, James Sweet wrote:

Michael Dobony wrote:
On Mon, 15 Dec 2008 13:26:35 -0500, Ernie Willson wrote:

My experience is that Ni-Cd's are virtually worthless (don't hold enough
charge). I have no experience with lithium ones. I'd recommend the NiMH's

Even if the charger is not designed for NiMH'S? Each type has its own
charging requirements. A few chargers will charge multiple types, however,
it is highly unlikely the charger for these special lights will accept
multiple types of batteries. Putting the wrong type in will likely cause a
fire.

HTH,


These lights use a simple "dumb charger", that is the charge current is
limited by a resistor. NiMH and NiCD are close enough electrically that
they are interchangeable in most situations. They will undoubtedly
withstand a higher charge rate than the light provides, but that isn't
an issue. Batteries with a higher mAh rating will take correspondingly
longer to charge, but with something that is plugged in all the time
that isn't really an issue.

It will not cause a fire.

Okay, will you pay for damages if it causes a fire? When you personally
sign responsibility for liability for any damages incurred, then I'd listen
to you, maybe.


Please explain how it will cause a fire.

If you don't want to listen to me that's fine, my advice is free. If
liability is a concern, don't replace the battery at all, throw away the
light and buy a new one.

"---MIKE---" wrote in message
...
I have three "power-off" lights that are dead because the batteries have
died. They take two AA batteries which I want to replace. Which type
would be the best - Lithium, Nickel-Cadmium, or Nickel Metal Hydride?
They would be plugged in and constantly charging until the power goes
off.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')

You are betting your life and the lives of others on these lights
functioning. Don't accept any half baked ideas you might get here. Read
and follow the manual.

In my life, there has been many an item that specifically said what battery
to use and which not to use. I have ignored or just not read these
statements. They weren't things, though, that were life-saving devices, so
my poor reading skills didn't make a very big difference.

This can make the difference in life and death. Be sure.

PERIOD.

Steve

On Dec 15, 4:56*pm, James Sweet wrote:
Michael Dobony wrote:
On Mon, 15 Dec 2008 10:50:48 -0800, James Sweet wrote:

Michael Dobony wrote:
On Mon, 15 Dec 2008 13:26:35 -0500, Ernie Willson wrote:

My experience is that Ni-Cd's are virtually worthless (don't hold enough
charge). I have no experience with lithium ones. I'd recommend the NiMH's

Even if the charger is not designed for NiMH'S? *Each type has its own
charging requirements. *A few chargers will charge multiple types, however,
it is highly unlikely the charger for these special lights will accept
multiple types of batteries. *Putting the wrong type in will likely cause a
fire.

HTH,

These lights use a simple "dumb charger", that is the charge current is
limited by a resistor. NiMH and NiCD are close enough electrically that
they are interchangeable in most situations. They will undoubtedly
withstand a higher charge rate than the light provides, but that isn't
an issue. Batteries with a higher mAh rating will take correspondingly
longer to charge, but with something that is plugged in all the time
that isn't really an issue.

It will not cause a fire.

Okay, will you pay for damages if it causes a fire? *When you personally
sign responsibility for liability for any damages incurred, then I'd listen
to you, maybe.

Please explain how it will cause a fire.

If you don't want to listen to me that's fine, my advice is free. If
liability is a concern, don't replace the battery at all, throw away the
light and buy a new one.- Hide quoted text -

- Show quoted text -

Everything James Sweet has written on the battery question is 100%
correct, for my 2 Cents opinion, and I have worked with Nicads since
back in the late 1950's when we at Bell Labs were experimenting with
them for backup power for electronic switching systems for the Bell
System in place of the lead-acid batteries then in use, because of the
hazards of using the lead-acid cells. Some of those early nicads
actually lasted for 25 years, but of course they were treated
carefully as far as charging current and they used much higher quality
chemistry than the cheap cells you generally buy these days.,

hr(bob) wrote:
On Dec 15, 4:56 pm, James Sweet wrote:
Michael Dobony wrote:
On Mon, 15 Dec 2008 10:50:48 -0800, James Sweet wrote:
Michael Dobony wrote:
On Mon, 15 Dec 2008 13:26:35 -0500, Ernie Willson wrote:
My experience is that Ni-Cd's are virtually worthless (don't hold enough
charge). I have no experience with lithium ones. I'd recommend the NiMH's
Even if the charger is not designed for NiMH'S? Each type has its own
charging requirements. A few chargers will charge multiple types, however,
it is highly unlikely the charger for these special lights will accept
multiple types of batteries. Putting the wrong type in will likely cause a
fire.
HTH,
These lights use a simple "dumb charger", that is the charge current is
limited by a resistor. NiMH and NiCD are close enough electrically that
they are interchangeable in most situations. They will undoubtedly
withstand a higher charge rate than the light provides, but that isn't
an issue. Batteries with a higher mAh rating will take correspondingly
longer to charge, but with something that is plugged in all the time
that isn't really an issue.
It will not cause a fire.
Okay, will you pay for damages if it causes a fire? When you personally
sign responsibility for liability for any damages incurred, then I'd listen
to you, maybe.
Please explain how it will cause a fire.

If you don't want to listen to me that's fine, my advice is free. If
liability is a concern, don't replace the battery at all, throw away the
light and buy a new one.- Hide quoted text -

- Show quoted text -

Everything James Sweet has written on the battery question is 100%
correct, for my 2 Cents opinion, and I have worked with Nicads since
back in the late 1950's when we at Bell Labs were experimenting with
them for backup power for electronic switching systems for the Bell
System in place of the lead-acid batteries then in use, because of the
hazards of using the lead-acid cells. Some of those early nicads
actually lasted for 25 years, but of course they were treated
carefully as far as charging current and they used much higher quality
chemistry than the cheap cells you generally buy these days.,

I always tell people, if they want to know
about backup battery power, talk to the guys
who work on the backup batteries for the phone
company. I don't think anyone has more knowhow
when it comes to the care and feeding of lead
acid cells.

TDD

I went shopping today. The only type of rechargeable batteries at
Wal-mart in the AA size were Lithium and NiMH. I bought the NiMH
(Duracell), and will try them.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')

On Tue, 16 Dec 2008 14:00:12 -0500,
(---MIKE---) wrote:

I went shopping today. The only type of rechargeable batteries at
Wal-mart in the AA size were Lithium and NiMH. I bought the NiMH
(Duracell), and will try them.

There are no rechargeable Lithium AA's

"---MIKE---" wrote in message
...
I went shopping today. The only type of rechargeable batteries at
Wal-mart in the AA size were Lithium and NiMH. I bought the NiMH
(Duracell), and will try them.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')

What did your manual say?



Steve

James Sweet wrote:


Much debate has raged over the years on the topic of NiCD memory
effects, and to this day it remains controversial as to whether the
memory effect exists. My own experimentation suggests that the perceived
memory effect is due to poor quality chargers that severely overcharge
cells in the specified time unless they are discharged first, leading to
a dramatic reduction in lifespan.

I've seen it with NiCads. You charge one and it appears to be
discharged after brief use. Then you put it in a holder with a 2-ohm
shunt, and it keeps producing current, but the voltage is low because
the internal resistance is high. With the high internal resistance, it
may take a long time to discharge completely. Completely discharging
gets rid of the high resistance.

It appears that if a NiCad is left charged or partially charged for a
long time, a chemical change will cause high resistance in the charged
part, but discharging will correct it. Lead-acid seems the opposite; if
it is not routinely fully charged, the discharged part will develop high
resistance, which can be corrected by fully charging, which can take a
long time due to the high resistance.

NASA says NiCads should be drained and shorted if not needed
immediately. When you get ready to use them, the first step is to
overcharge them, 40 hours at C/20.

Sometimes a NiMH may not charge fully. I think that's from gas bubbles
and not memory effect.

On a related note, years ago I got tired of the
backup battery in my digital clocks always being dead whenever I needed
it so I did a simple modification and installed a 1K resistor across the
isolating diode for the backup battery resulting in the power supply in
the clock providing a steady 3-5mA of current to a NiCD "9V" (really
7.2V) battery. This has been working great, and more than 6 years later
the original batteries in the four clocks I modified are still working
great despite being trickle charged steadily for those years.

In my experience, keeping a NiCad charged eventually results in memory
effect, which can be corrected. If you removed one of your batteries, I
wonder if it would provide 8.2V across 150 ohms for a couple of hours.
If it won't, that could be memory effect.

In my experience, slow or trickle charging NiCads causes electrical
leakage and eventually shorting. Internal electrical leakage can be
detected by testing capacity after two weeks off the charger.


In a nutshell, at high enough current level to charge a battery quickly,
180-500mA or more being typical, charge time is very important and once
the cell reaches full charge that energy will go into heating the cell
rather than the chemical reaction that stores energy. If you keep that
up, the electrolyte will vent and permanent damage will occur. On the
other hand, if you charge a cell at a low current of say 5-10mA, you can
charge it indefinitely without damage.

I think the heating comes from the gases recombining. I wonder if the
heat can damage a cell even if there is no venting. (I like to check
temperature with an infrared thermometer.)

They both have a nominal cell voltage of
1.2V, they both have a recommended standard charge current of C/10,
where C is the mAh rating of the cell, and they both need to be charged
by a current limited source with an OCV higher than the nominal cell
voltage, and both can be trickle or float charged indefinitely at C/100
or so. This is based on my education, research, and years of personal
experience. If you insist that this is incorrect, please cite sources.

Are C/10 and trickle charging really recommended for NiMH? In my
experience, both kinds of cells do better if I stick to
microprocessor-controlled fast chargers.

On Tue, 16 Dec 2008 19:44:00 -0500, E Z Peaces wrote:
In my experience, keeping a NiCad charged eventually results in memory
effect, which can be corrected. If you removed one of your batteries, I
wonder if it would provide 8.2V across 150 ohms for a couple of hours.
If it won't, that could be memory effect.

My experience with both kinds of batteries is that if I remove a set from
service and let it sit idle for more than a few months, they'll be ruined.
Every time.