C2100 battery memory effect

This has probably been covered before, but I wasn't able to find a thread after a quick search:

How much of an issue, if any, is the battery "memory" effect with the Olympus 1600 rechargeables and the BU-100E recharger that comes with the camera?

In other words, is it important to allow a set of batteries to reach almost complete discharge before plopping them back in the charger?

I have gotten into the habit of frequently "topping off" the batteries at the end of the day, even when the camera indicates plenty of charge left. (Of course, I have several sets of batteries, so I always have a fresh set to install in the camera.)

So......am I paying a price in reduced battery life by "topping off" in this way? Or (hopefully!) will the batteries be restored to full life even when recharged repeatedly after partial discharge?

TIA for your thoughts,

David

It is ok to "top off" or partially discharge them. They do lose capacity but slowly. About every 20 cycles you can drain down to nil and fully charge to restore them. The Maha C204 charger has this feature.

DF said:

This has probably been covered before, but I wasn't able to find a
thread after a quick search:

How much of an issue, if any, is the battery "memory" effect with
the Olympus 1600 rechargeables and the BU-100E recharger that comes
with the camera?

In other words, is it important to allow a set of batteries to
reach almost complete discharge before plopping them back in the
charger?

I have gotten into the habit of frequently "topping off" the
batteries at the end of the day, even when the camera indicates
plenty of charge left. (Of course, I have several sets of
batteries, so I always have a fresh set to install in the camera.)

So......am I paying a price in reduced battery life by "topping
off" in this way? Or (hopefully!) will the batteries be restored
to full life even when recharged repeatedly after partial discharge?

TIA for your thoughts,

David

Click to expand...

Maybe someone can clear something up for me. I thought the BU-100 charger, which came with my camera, first "discharged" the batteries then charged them. Yes/No?

Ed Pearson said:

DF said:

This has probably been covered before, but I wasn't able to find a
thread after a quick search:

How much of an issue, if any, is the battery "memory" effect with
the Olympus 1600 rechargeables and the BU-100E recharger that comes
with the camera?

In other words, is it important to allow a set of batteries to
reach almost complete discharge before plopping them back in the
charger?

I have gotten into the habit of frequently "topping off" the
batteries at the end of the day, even when the camera indicates
plenty of charge left. (Of course, I have several sets of
batteries, so I always have a fresh set to install in the camera.)

So......am I paying a price in reduced battery life by "topping
off" in this way? Or (hopefully!) will the batteries be restored
to full life even when recharged repeatedly after partial discharge?

TIA for your thoughts,

David

Click to expand...

Click to expand...

As far as I can tell, after reading what seems like every battery site on the web, NiMh batteries do not suffer from the memory effects that plain NiCads apparently do.

I have noticed that with some NiMh batteries they need to be fully charged and discharged a few times before they give full performance.

I built my own headlight system for my mountain bike and have measured this effect on many different batteries (all made by Sanyo though). They batteries performed at 1/3 of spec'ed capacity until several deep discharge/charge cycles.

On the other hand, the OEM batteries w/the Olympus worked fine from the start. Does Olympus condition the batteries before shipping? I have no idea.

My guess is that for maximum bang for the buck from your batteries, try to run them through full cycles . . . especially during early use . . . but later on don't worry about just topping them off if you need to (like before going out on a shoot).

According to http://www.greenbatteries.com/ , NiMH batteries do not "carry a charge" like NiCads do. Therefore, although "topping off" isn't necessary if you have multiple sets of batteries, it certainly won't affect the life of the batteries.

DF said:

How much of an issue, if any, is the battery "memory" effect with
the Olympus 1600 rechargeables and the BU-100E recharger that comes
with the camera?

In other words, is it important to allow a set of batteries to
reach almost complete discharge before plopping them back in the
charger?

Click to expand...

I can't speak for the BU-100 charger since I use the Maha. Mine has a button to start the conditioning cycle and LED indicators that show it's progress. It is not automatic as you don't normally need it. You could do a test on yours. Charge the batteries then take them out for a day. Put them back in and note the time to full charge again. If it's short then it's topping off. If it's much longer then it's draining and recharging. Don't leave them out for more than a few days as they will drain by themselves in about a month.

JimD said:

Maybe someone can clear something up for me. I thought the BU-100
charger, which came with my camera, first "discharged" the
batteries then charged them. Yes/No?

Click to expand...

Contrary to what most sites say about NiMh natteries not having suffering from the memory effect like NiCds, it is simply not true. These sites would prefer to sell you the more expensive MiMh batteries if they can. The NiMh advantage is increased capacity. They need to be discharged periodically to reduce the effect just like NiCds. The more you top off batteries the shorter the life of the batteries will be even with periodic discharging.

Kerry

tko said:

As far as I can tell, after reading what seems like every battery
site on the web, NiMh batteries do not suffer from the memory
effects that plain NiCads apparently do.

I have noticed that with some NiMh batteries they need to be fully
charged and discharged a few times before they give full
performance.

I built my own headlight system for my mountain bike and have
measured this effect on many different batteries (all made by
Sanyo though). They batteries performed at 1/3 of spec'ed capacity
until several deep discharge/charge cycles.

On the other hand, the OEM batteries w/the Olympus worked fine from
the start. Does Olympus condition the batteries before shipping? I
have no idea.

My guess is that for maximum bang for the buck from your batteries,
try to run them through full cycles . . . especially during early
use . . . but later on don't worry about just topping them off if
you need to (like before going out on a shoot).

Click to expand...

Hate to say this, Kerry, but you are the first to espouse this opinion. I have read that an occasional deep discharge is a good thing, as well as recommended when batteries are new. But the overwhelming data I've seen is that partial discharge then recharge is not the least harmful to NiMis. Since MAHA did include the deep discharge cycle as an option (button selectable) it is safe to assume an occasional deep discharge may be beneficial, but not totally necessary.

While on the battery subject, I have noticed my Olympus batteries seem to hold a higher charge and last longer than any other NiMis I have ever tried. By quite a long shot! And the charger charges more rapidly than any I've ever used. So rapid, in fact, that the batteries almost get hot to the touch, and I've noticed the beginnings of a grey/black discloration in spots on the light colored negative band around the cells. Anyone else notice this?

Kerry said:

Kerry

tko said:

As far as I can tell, after reading what seems like every battery
site on the web, NiMh batteries do not suffer from the memory
effects that plain NiCads apparently do.

I have noticed that with some NiMh batteries they need to be fully
charged and discharged a few times before they give full
performance.

I built my own headlight system for my mountain bike and have
measured this effect on many different batteries (all made by
Sanyo though). They batteries performed at 1/3 of spec'ed capacity
until several deep discharge/charge cycles.

On the other hand, the OEM batteries w/the Olympus worked fine from
the start. Does Olympus condition the batteries before shipping? I
have no idea.

My guess is that for maximum bang for the buck from your batteries,
try to run them through full cycles . . . especially during early
use . . . but later on don't worry about just topping them off if
you need to (like before going out on a shoot).

Click to expand...

Click to expand...

Carol has it straight. NiMH batteries do not have memory--period. They are not capable of mimicking the NiCad memory problem. When NiMH (as with most batteries) are rapidly charged, they will get hot. This does not shorten their lives or cause damage. they never need full discharging, and can be topped off at one's pleasure without adverse effect. Period.

John R.

Carol said:

DF said:

How much of an issue, if any, is the battery "memory" effect with
the Olympus 1600 rechargeables and the BU-100E recharger that comes
with the camera?

In other words, is it important to allow a set of batteries to
reach almost complete discharge before plopping them back in the
charger?

Click to expand...

Click to expand...

John R. said:

Carol has it straight. NiMH batteries do not have memory--period.
They are not capable of mimicking the NiCad memory problem. When
NiMH (as with most batteries) are rapidly charged, they will get
hot. This does not shorten their lives or cause damage. they
never need full discharging, and can be topped off at one's
pleasure without adverse effect. Period.

John R.

Click to expand...

What about if the batteries are left in the Olympus (BU-100E) recharger for some length of time after they have been recharged? The indicator light on the charger goes out when full charge is reached, but will it damage the batteries in any way or shorten their life if they are not removed from the charger promptly?

John: Sorry but you are in error. A little research on the subject and the chemistries envolved yields the following indicating that NIMH batteries do indeed have a memory effect. Period! You can find this in many places on the internet if you just look.

"Memory effect and discharging conditioning batteries:

Discharging a battery will prevent "memory effect" from building up in NiCd and NiMH batteries. As a rule NiCd batteries should be discharged after 1 or 2 charge cycles, and NiMH should be discharged after 5 or 6 charge cycles. Every time a battery receives a charge, (even a few minutes) will count as one charge cycle. NiMH batteries DO build up "memory" like NiCd, it just takes a while longer. The only true "NO MEMORY" battery is lithium."

Kerry

John R. said:

John R.

Carol said:

DF said:

How much of an issue, if any, is the battery "memory" effect with
the Olympus 1600 rechargeables and the BU-100E recharger that comes
with the camera?

In other words, is it important to allow a set of batteries to
reach almost complete discharge before plopping them back in the
charger?

Click to expand...

Click to expand...

Click to expand...

Well now! We have two diametrically opposed viewpoints.

John states emphatically, and with punctuation, that NiMH batteries do not exhibit a memory effect.

Kerry maintains with equal vigor that they do.

Both cannot be correct.

This is an empirical issue, resolvable by evidence. Anyone know a qualified electro-chemical engineer to whom we could pose the question?

David

I know a little about the chemistry of both and the reason for the NiCd memory effect.

In NiCds if you don't allow them to discharge larger crystals form inside the battery, larger crystals mean less surface area for reactions to take place, so the capacity decreases. Deep discharge on NiCds keeps the crystals small.

In NiMH batteries the Nickel metal basically acts like a sponge to hold hydrogen for the reaction. It's been several years since I looked at the actual reactions so I don't remember what form the hydrogen is in. The 'sponge' should be capable of releasing and accepting hydrogen with no memory effect. This is why you can maintain them with a trickle charge. As with any rechargeable battery if there is contamination in the chemicals used in production they will build up on the 'sponge' and decrease the capacity of the battery with each recharge. So a well made NiMH battery should not need to be reconditioned very often.

Someone mentioned using them in a lamp, discharging them too far can also cause damage. Chargers that do reconditioning will drain them more than the automatic shut off in cameras, but not as far as putting them in a flashlight.

I wouldn't needlessly put NiMH batts through reconditioning, wait till you notice a decrease in capacity. With NiCds reconditioning every so many cycles does make them last longer because you are breaking down the larger crystals that form during charging.

Thanks, Marty.

Very interesting explanation. I will interpret that as a vote for John's position. (...Although you do suggest that NiMHs might benefit from an occasional "deep discharge" reconditioning, due to possible contamination of the chemicals in manufacturing and such. In any case, you seem rather clear that the memory effect is far less of an issue with NiMhs than with NiCds, thus supporting John.)

David

Marty Schultz said:

I know a little about the chemistry of both and the reason for the
NiCd memory effect.

In NiCds if you don't allow them to discharge larger crystals form
inside the battery, larger crystals mean less surface area for
reactions to take place, so the capacity decreases. Deep discharge
on NiCds keeps the crystals small.

In NiMH batteries the Nickel metal basically acts like a sponge to
hold hydrogen for the reaction. It's been several years since I
looked at the actual reactions so I don't remember what form the
hydrogen is in. The 'sponge' should be capable of releasing and
accepting hydrogen with no memory effect. This is why you can
maintain them with a trickle charge. As with any rechargeable
battery if there is contamination in the chemicals used in
production they will build up on the 'sponge' and decrease the
capacity of the battery with each recharge. So a well made NiMH
battery should not need to be reconditioned very often.

Someone mentioned using them in a lamp, discharging them too far
can also cause damage. Chargers that do reconditioning will drain
them more than the automatic shut off in cameras, but not as far as
putting them in a flashlight.

I wouldn't needlessly put NiMH batts through reconditioning, wait
till you notice a decrease in capacity. With NiCds reconditioning
every so many cycles does make them last longer because you are
breaking down the larger crystals that form during charging.

Click to expand...

Bob...I agree with you on the "Oly" batteries holding their charge longer than others. I use the MAHA 204F as a charger but the Powerex batteries that came with it definitely do not hold a charge as long as the Oly batteries.

BillyBob

Bob Adams said:

Hate to say this, Kerry, but you are the first to espouse this
opinion. I have read that an occasional deep discharge is a good
thing, as well as recommended when batteries are new. But the
overwhelming data I've seen is that partial discharge then recharge
is not the least harmful to NiMis. Since MAHA did include the deep
discharge cycle as an option (button selectable) it is safe to
assume an occasional deep discharge may be beneficial, but not
totally necessary.

While on the battery subject, I have noticed my Olympus batteries
seem to hold a higher charge and last longer than any other NiMis I
have ever tried. By quite a long shot! And the charger charges
more rapidly than any I've ever used. So rapid, in fact, that the
batteries almost get hot to the touch, and I've noticed the
beginnings of a grey/black discloration in spots on the light
colored negative band around the cells. Anyone else notice this?
Kerry wrote:;

Click to expand...

Bob Adams said:

Bob Adams said:

Contrary to what most sites say about NiMh natteries not having
suffering from the memory effect like NiCds, it is simply not true.
These sites would prefer to sell you the more expensive MiMh
batteries if they can. The NiMh advantage is increased capacity.
They need to be discharged periodically to reduce the effect just
like NiCds. The more you top off batteries the shorter the life of
the batteries will be even with periodic discharging.

Kerry

tko said:

As far as I can tell, after reading what seems like every battery
site on the web, NiMh batteries do not suffer from the memory
effects that plain NiCads apparently do.

I have noticed that with some NiMh batteries they need to be fully
charged and discharged a few times before they give full
performance.

I built my own headlight system for my mountain bike and have
measured this effect on many different batteries (all made by
Sanyo though). They batteries performed at 1/3 of spec'ed capacity
until several deep discharge/charge cycles.

On the other hand, the OEM batteries w/the Olympus worked fine from
the start. Does Olympus condition the batteries before shipping? I
have no idea.

My guess is that for maximum bang for the buck from your batteries,
try to run them through full cycles . . . especially during early
use . . . but later on don't worry about just topping them off if
you need to (like before going out on a shoot).

Click to expand...

Click to expand...

Click to expand...

DF said:

What about if the batteries are left in the Olympus (BU-100E)
recharger for some length of time after they have been recharged?
The indicator light on the charger goes out when full charge is
reached, but will it damage the batteries in any way or shorten
their life if they are not removed from the charger promptly?

Click to expand...

I left my batteries in the charger for about 5 days and they would not turn on the camera when I tried to use them. I reinserted them in the camera 2 or 3 times and it didn't help. When I put them back in the charger they charged for about an hour befor the red light went off. I've had no problems with them since then, but I take them out of the charger when they are charged now.

Aha....that's interesting, Bob. I try to remove mine from the charger as soon as I can after the light goes out, but sometimes it's a few hours later before I can get to it.

David

bob lemon said:

bob lemon said:

What about if the batteries are left in the Olympus (BU-100E)
recharger for some length of time after they have been recharged?
The indicator light on the charger goes out when full charge is
reached, but will it damage the batteries in any way or shorten
their life if they are not removed from the charger promptly?

Click to expand...

I left my batteries in the charger for about 5 days and they would
not turn on the camera when I tried to use them. I reinserted them
in the camera 2 or 3 times and it didn't help. When I put them back
in the charger they charged for about an hour befor the red light
went off. I've had no problems with them since then, but I take
them out of the charger when they are charged now.

Click to expand...

Found some info about NIMH batteries here:

http://data.energizer.com/batteryinfo/application_manuals/nickel_metal_hydride.htm

Here is the section about memory effect:
----------------------------------------------------------------------------
Memory/Voltage Depression

The issue of "memory" or voltage depression has been a concern for many designers of devices, using nickel-cadmium cells. In some applications where nickel-cadmium cells are routinely partially discharged, a depression in the discharge voltage profile of approximately 150 mV per cell has been reported when the discharge extends from the routinely discharged to rarely discharged zones. While the severity of this problem in nickel-cadmium cells is open to differing interpretations, the source of the effect is generally agreed to be in the structure of the cadmium electrode. With the elimination of cadmium in the nickel-metal hydride cell, memory is no longer a concern.
-----------------------------------------------------------------------------

Also, check the LIFE section towards the end of the page.
There are apparently other concerns which will shorten the life of the
cell. Overcharging and Over-Discharging...

-----------------------------------------------------------------------------
Cell Reversal

Discharge of nickel-metal hydride batteries to the degree that some or all of the cells go into reverse can shorten cell life, especially if this overdischarge is repeated routinely.

Prolonged Storage under Load

Maintaining a load on a cell (or battery) past the point of full discharge may eventually cause irreversible changes in the cell chemistry and promote life-limiting phenomena such as creep leakage.
-----------------------------------------------------------------------------

DF said:

Well now! We have two diametrically opposed viewpoints.

John states emphatically, and with punctuation, that NiMH batteries
do not exhibit a memory effect.

Kerry maintains with equal vigor that they do.

Both cannot be correct.

This is an empirical issue, resolvable by evidence. Anyone know a
qualified electro-chemical engineer to whom we could pose the
question?

David

Click to expand...

Very helpful information, Eugene. Thanks.

This, too, supports John's position that a "memory effect" is not an issue with NiMH batteries.

However, it was interesting to read the information about possible life-shortening consequences from over-charging OR over-discharging the batteries. I suppose this would argue for the wisdom of "topping off" the batteries rather than forcing them to completely discharge.

David

Eugene Abel said:

Found some info about NIMH batteries here:

http://data.energizer.com/batteryinfo/application_manuals/nickel_metal_hydride.htm

Here is the section about memory effect:
----------------------------------------------------------------------------
Memory/Voltage Depression

The issue of "memory" or voltage depression has been a concern for
many designers of devices, using nickel-cadmium cells. In some
applications where nickel-cadmium cells are routinely partially
discharged, a depression in the discharge voltage profile of
approximately 150 mV per cell has been reported when the discharge
extends from the routinely discharged to rarely discharged zones.
While the severity of this problem in nickel-cadmium cells is open
to differing interpretations, the source of the effect is generally
agreed to be in the structure of the cadmium electrode. With the
elimination of cadmium in the nickel-metal hydride cell, memory is
no longer a concern.
-----------------------------------------------------------------------------

Also, check the LIFE section towards the end of the page.
There are apparently other concerns which will shorten the life of the
cell. Overcharging and Over-Discharging...

-----------------------------------------------------------------------------
Cell Reversal
Discharge of nickel-metal hydride batteries to the degree that some
or all of the cells go into reverse can shorten cell life,
especially if this overdischarge is repeated routinely.

Prolonged Storage under Load
Maintaining a load on a cell (or battery) past the point of full
discharge may eventually cause irreversible changes in the cell
chemistry and promote life-limiting phenomena such as creep leakage.
-----------------------------------------------------------------------------

Click to expand...

Time to answer the mail. What we all commonly refer to as memory effect in NiCd and MiMh batteries is a misnomer for voltage depression. Both NiMh and NiCds experience this effect but NiMh to a lesser extent so technically speaking, John is correct. True memory effect is almost never happens, even in NiCds. However, what is most commonly referred to as memory effect (voltage depression) does in both battery types.

Voltage depression can be minimized by proper battery care. The more often you top off a charge the sooner voltage depression will occur and, the more often discharge will be required to re-condition the batteries. The more frequently batteries are reconditioned, the shorter the life of the battery. For maximum life, one should use the batteries in the camera until the low battery indicator flashes. Then, they should be replaced with a spare charged set and those removed from the camera, recharged.

Batteries should be discharged using a discharge capable charger designed to accommodate the type of batteries being used, NiCd or NiMh, only when the service time of freshly charged batteries becomes noticeably shorter. This will maximize the life of the batteries. Caution! Using a NiMh Fast charger on NiCd batteries may cause overheating and possible a fire depending on the charger.

The following is an excerpt from

http://www.wppltd.demon.co.uk/WPP/Batteries/Memory/memory.html describing the memory effect and voltage depression.

"Does the memory effect exist?

Yes and no. The "real" memory effect as reported in certain space borne applications and caused by persistent under charging of a partially discharged cell is almost certainly never seen in mobile phone batteries or any others in terrestrial service except in certain very unusual circumstances.

Much more commonly there is AN effect, properly called voltage depression, which people now tend to refer to as "memory effect". This is a bit unfortunate as the cause (and cure) is different from the true memory effect. For details - read on:-

First of all, the term "memory effect" is quite unscientific. People tend to attribute any failure of a NiCd to memory. Let us define memory as the phenomenon where the discharge voltage for a given load is lower than it should be.

This can give the appearance of a lowered capacity, while in reality, it is more accurate to term it voltage depression. Memory is also hard to reproduce, which makes it hard to study. Originally, memory effect was seen in spacecraft batteries subjected to a repeated discharge/charge cycle that was a fixed percentage of total capacity (due to the earth's shadow). After many cycles, when called upon to provide the full capacity, the battery failed to do so. Since we aren't in space, the above is not really relevant.

Voltage depression is more severe in NiCd batteries than in NiMH. The explanation below concentrates on NiCd, the same principles apply to both."

""To recap, we can say that true 'memory' is exceedingly rare. When we see poor battery performance attributed to 'memory', it is almost always certain to be a correctable application problem. Of the...problems noted above, Voltage Depression is the one most often mistaken for 'memory'.....Bob Myers"

DF said:

This, too, supports John's position that a "memory effect" is not
an issue with NiMH batteries.

However, it was interesting to read the information about possible
life-shortening consequences from over-charging OR over-discharging
the batteries. I suppose this would argue for the wisdom of
"topping off" the batteries rather than forcing them to completely
discharge.

David

Eugene Abel said:

Found some info about NIMH batteries here:

http://data.energizer.com/batteryinfo/application_manuals/nickel_metal_hydride.htm

Here is the section about memory effect:
----------------------------------------------------------------------------
Memory/Voltage Depression

The issue of "memory" or voltage depression has been a concern for
many designers of devices, using nickel-cadmium cells. In some
applications where nickel-cadmium cells are routinely partially
discharged, a depression in the discharge voltage profile of
approximately 150 mV per cell has been reported when the discharge
extends from the routinely discharged to rarely discharged zones.
While the severity of this problem in nickel-cadmium cells is open
to differing interpretations, the source of the effect is generally
agreed to be in the structure of the cadmium electrode. With the
elimination of cadmium in the nickel-metal hydride cell, memory is
no longer a concern.
-----------------------------------------------------------------------------

Also, check the LIFE section towards the end of the page.
There are apparently other concerns which will shorten the life of the
cell. Overcharging and Over-Discharging...

-----------------------------------------------------------------------------
Cell Reversal
Discharge of nickel-metal hydride batteries to the degree that some
or all of the cells go into reverse can shorten cell life,
especially if this overdischarge is repeated routinely.

Prolonged Storage under Load
Maintaining a load on a cell (or battery) past the point of full
discharge may eventually cause irreversible changes in the cell
chemistry and promote life-limiting phenomena such as creep leakage.
-----------------------------------------------------------------------------

Click to expand...

Click to expand...