I have a sanyo charger model: NC-MQN04ENS

[Rosoku Chikara]

...when removing a battery what did you remove first the negative side or the positive for AAA and also for AA?
i noticed that i scratched the label in my AAA ...<snip>

Well, to tell you the truth, I never really thought about it before. The only problem, if you wish to call it a "problem," that I ever had was when I first inserted AAAs. As you already know now, AAAs must go in Negative first, and then push the Positive down, until you get a nice "click." Then, you can rotate (spin) the cell a little while pushing it down, just to make certain you have a good connection.

As for, removal of AAAs, I had to check. I usually just "snatch" them out, and I never paid any attention as to how I was doing it. Having just checked, it seems to me that they come out about both ends at the same time, but perhaps Positive end comes out a bit sooner. Anyway, they come out much easier than AAs.

To insert AAs, I also put Negative in first, but I see by checking just now, that it is possible to put Positive first, and this may be better (recommended by some users). After I insert AAs, I also rotate them a little to confirm the good connection, but this is probably not important.

But, as for removal, I cannot remove AAs any other way than Negative first. In the case of my MH-C9000, I cannot remove Positive first on AA cell. Even if I try to remove Positive first, the Negative end comes up, even when I am pulling on Positive end. (I read where some people compress the negative tang enough, but I cannot seem to do it.)

I am sorry to hear about the scratched label on your AAA. I never noticed any label (wrapper) damage to any of my cells, but I know others have had this problem.

Here is a quote from the thread link I posted above:

...Although the manual suggest inserting the positive end of the AA cell in first and removing it last, this can cause torn wrappers on the bottom end of the cell. To avoid this, users are choosing to seat the negative end first; then exerting enough pressure on the cell to compress the negative tang and allow the positive end to slip into (and out of) place...<snip>

 

[LightX]

Hi im having a doubt regarding one of my eneloop xx aaa 950 mah

i fully charged my eneloop xx at 400mA after that i discharged it at 200mA and charge again i get this result:

Discharge. Charge mah and voltage result
a.906mah. 887mah 1.46v (finished first) (887mah only)
b.907mah. 924mah 1.45v
c.910mah. 930mah 1.46v
d.911mah. 923mah 1.45v

after getting this results i exchaged cell A and cell C and charge it again, after 1 min it appears that they all get 1.47v.

Why is it on cell A i got 887 mah (charged) from 906 mah (discharge) and it is left behind, the rest continued charging up to 924mah 930mah and 923mah

is my cell A broken?

 

[Rosoku Chikara]

...is my cell A broken?...<snip>

I think it is too soon to say your cell "A" is "broken." (Also, "broken" is probably the wrong word, regardless.)

My first question is: how do you intend to use these four AAA cells? Do you plan to use them all four together in some flashlight or other device as a "matched set"? One at a time? Two at a time?

(The following is some more information for you, but I would like to know the answer to the above question before I try to give you any more detailed suggestions.)

I have read that for the "first few cycles" NiMH cells often do not reach their full capacity. They may need to be "broken in" like a pair of new shoes, before they get "comfortable." So, depending on how you intend to use these cells, perhaps you can go ahead and start using them, and then check their capacity performance again later.

Do not worry (take too seriously) about the 950 mAh rating of your Eneloop XX cells. Sanyo/Panasonic changed their rating method occasionally, depending on the market, and some legal/warranty issues. Mine are rated at "only" 900 mAh but I think they are all pretty much the same cells.

As you know, I have tested the capacity of a large number of AAA Eneloop Pro cells with my MH-C9000, and just for your information, the lowest capacity I have ever gotten is: 901 mAh. And, the highest is: 945 mAh. (As you can see, that is 4.9% variation. By contrast, your four cells are showing only 4.8% variation.)

I use most of my AAA cells in groups of four, so I test them all first, and try to group them together in matched sets with the lowest variation possible among the four cell groups. After such "matching," the typical variation among my groups is less than 2%, but I understand that up to 5% variation is "acceptable" even for a so-called "matched set." (In any case, matching cells in NiMH is not a safety issue, just a performance or efficiency issue. Frankly, I do not think it really matters at all, unless you intend to drain your cells completely "dead," or almost completely "dead," before recharging.)

Anyway, I think maybe the capacity of your cell "A" will most likely increase some over time. Since you did not use the MAHA "BREAK-IN" procedure (And, that is OK, it takes such a very long time. And, there is no real need to do it.), I think it is quite likely that your cell may not yet be delivering its best performance. So, I would not worry too much about it. (At least not yet.)

Generally speaking, I would say that even if 887 mAh is the true capacity, that is still a very good AAA cell. I have no idea where you purchased your Eneloop XX cells, but if you think you can return them for refund, that is of course your decision. But, personally, I do not yet think that your cell "A" is truly defective.

 

[LightX]

I think it is too soon to say your cell "A" is "broken." (Also, "broken" is probably the wrong word, regardless.)

Hi,

My first question is: how do you intend to use these four AAA cells? Do you plan to use them all four together in some flashlight or other device as a "matched set"? One at a time? Two at a time?

-i used them all 4 together in my ledlenser p7.2

I have read that for the "first few cycles" NiMH cells often do not reach their full capacity. They may need to be "broken in" like a pair of new shoes, before they get "comfortable." So, depending on how you intend to use these cells, perhaps you can go ahead and start using them, and then check their capacity performance again later.

-So maybe ill just use them and see if the cell "A" performance improves or should i try break in mode or refresh and analyze?

Do not worry (take too seriously) about the 950 mAh rating of your Eneloop XX cells. Sanyo/Panasonic changed their rating method occasionally, depending on the market, and some legal/warranty issues. Mine are rated at "only" 900 mAh but I think they are all pretty much the same cells.

-Mine states in the packaging 950 mah typical capacity and 900 minimum capacity, but it should fall above 900 mah threshold.

As you know, I have tested the capacity of a large number of AAA Eneloop Pro cells with my MH-C9000, and just for your information, the lowest capacity I have ever gotten is: 901 mAh. And, the highest is: 945 mAh. (As you can see, that is 4.9% variation. By contrast, your four cells are showing only 4.8% variation.)

-wow atleast your lowest capacity got qualified in 900 mah rated minimum capacity, mine only charged 887 mah and i noticed that it stops charging ahead of time while others are still charging there's a long time delay beween the cell B

I use most of my AAA cells in groups of four, so I test them all first, and try to group them together in matched sets with the lowest variation possible among the four cell groups. After such "matching," the typical variation among my groups is less than 2%, but I understand that up to 5% variation is "acceptable" even for a so-called "matched set." (In any case, matching cells in NiMH is not a safety issue, just a performance or efficiency issue. Frankly, I do not think it really matters at all, unless you intend to drain your cells completely "dead," or almost completely "dead," before recharging.)

-i can't match it since i only have 4 pcs eneloop xx, is good if i discharged them completely before charging? i ran some test i discharged my eneloop until its done and insert it to my flashlight, when i turned it on the light is still strong.. i expected to get no light at all.

Anyway, I think maybe the capacity of your cell "A" will most likely increase some over time. Since you did not use the MAHA "BREAK-IN" procedure (And, that is OK, it takes such a very long time. And, there is no real need to do it.), I think it is quite likely that your cell may not yet be delivering its best performance. So, I would not worry too much about it. (At least not yet.)

-i hope so. maybe it didn't charged the cell thoroughly since i got closer results when i discharged them 906,907,910 and 911.. could it be that my maha c9000 slot 1 is faulty? lol..

Generally speaking, I would say that even if 887 mAh is the true capacity, that is still a very good AAA cell. I have no idea where you purchased your Eneloop XX cells, but if you think you can return them for refund, that is of course your decision. But, personally, I do not yet think that your cell "A" is truly defective.

-you think? hmm.. i bought it online, i doubt they will refund it since it has no warranty..

 

[Rosoku Chikara]

... i used them all 4 together in my ledlenser p7.2...<snip>

OK, so now I know how you will use these cells, so I can try to give you some more information. (I believe my information is correct, but others are more battery expert than I, so they may have different or better advice.)

So, first let's talk a little bit about what happens when you use 4x Eneelops together. (By the way, the LED Lenser P7.2 looks like a very nice flashlight!)

Your four cells: A, B, C, D each put out about 1.2v and I assume they are connected in series so total voltage is 4.8v to power the LED emitter. In the beginning, all four cells have plenty of energy (mAh), but as you use them, both their voltage and mAh is reduced. The problem may occur when one cell ("A") loses all of its energy before the other three cells. If energy of cell "A" goes to zero (completely dead) then the other three cells ("B," "C," and "D") may work together to "reverse charge" the cell "A."

Such "reverse charging" is very bad. In some rechargeable cells (like Li-Ion) or even some non-rechargeable cells (like CR123A) this can result in intense heat, release of poisonous gases, and even explosion. In the case of NiMH rechargeable cells (Eneloop) there are no safety risks that I know of. (I do not believe your Eneloop cells can ever explode.) But, I believe that such "reverse charging" can damage or destroy your Eneloop cell, so that you must replace it.

So, if you follow my description of the problem, then you can see that the simplest solution is to never drain all the energy from your "weakest" cell. In other words, if there is always enough energy (mAh) left in your cell "A," then your other cells will never try to "reverse charge" it. The benefit of matched cells (cells that contain as close as possible to the same amount of energy in each one) are that they can be safely drained down to "zero" or near "zero" (completely dead). In reality, this is usually only important in the "Hobby World" such as RC car racing. If you race RC cars, then having an excellent "matched" battery pack, can help you win races. But, for flashlights, I guess it is usually not so important.

In fact, since voltage is also being reduced as energy is being reduced, I think there is good chance that your LED Lenser P7.2 may stop working (due to low voltage) before your cells can ever be completely drained. (I believe that this is a common feature/design of many good LED flashlights. But, I do not know enough about your flashlight to say whether or not this is true. But, I think it is likely.) In my case, I worry a bit more about having "matched sets" because I use many of my AAA Eneloops in very cheap "emergency" flashlights which probably do not have such complex circuitry, so I believe that they can probably use all the energy down to zero (LED just gets dimmer, and dimmer... as the voltage gets lower and lower.)

So, for now, my suggestion is to use your Eneloops in your flashlight, but recharge them before they are fully drained. (I believe your flashlight gets about 4 hours run-time on regular high mode, and 2 hours run-time on "boost" mode. So, try using it for only about 3 hrs. on high, or about 1.5 hrs on "boost.") Don't worry, this is not a permanent restriction. It is just my recommendation while you attempt to break in your troublesome cell "A."

...i noticed that it stops charging ahead of time while others are still charging there's a long time delay between the cell B...<snip>

When you remove your cells from your flashlight, fully discharge them in your MH-C9000. Your MAHA will drain all four cells "completely" (or down to the "best" level), but this is "safe" because your MAHA is treating each cell differently in its own individual circuit. That is why you noticed above that your cell "A" stops charging a long time before the cell "B." It has less capacity, so it takes less time to charge. This is completely normal.

But, hopefully, as you use your cells in your flashlight this way, you will begin to notice that the capacity of cell "A" begins to improve each time you recharge it.

If it does not begin to improve, then eventually you may wish to try the time consuming "BREAK-IN" procedure, or perhaps even multiple "CYCLE" procedure. But, I understood from your posting, that you wished to avoid such time consuming procedures, and enjoy your LED Lenser P7.2 immediately. So that is why I suggest just using your cell for a while, and see what happens. (It should be no problem at all to use your cell "A," so long as you do not "over-discharge" it while connected to the other three cells, as I explained above.)

 

[Rosoku Chikara]

... could it be that my maha c9000 slot 1 is faulty? lol...<snip>

I guess anything is possible, but I think it is much more likely that your cell "A" just happens to (temporarily?) have lower capacity than your other three cells.

However, you should (of course) mark cell "A" in some way, so that you can keep track of its behavior from now on. Also, you can also watch "slot 1" of your MH-C9000 to see if it behaves in any abnormal or inconsistent way (in comparison with the other three slots).

Of course, you should try putting cell "A" in a different slot next time. If it charges normally in a different slot, and this time some other cell such a "C" which happens to be in "slot 1" charges poorly, this might indicate something unusual is going on with your MAHA.

 

[Rosoku Chikara]

...i ran some test i discharged my eneloop until its done and insert it to my flashlight, when i turned it on the light is still strong.. i expected to get no light at all...<snip>

I do not understand this part of your post. Can you explain in more detail exactly what you did? If you placed the cell into your 4xAAA flashlght, please explain the condition of each cell when you did so.

(Are you saying cell "A" was fully discharged by your MH-C9000 and placed into your 4xAAA flashlight, while the other three cells "B," "C," and "D" were still fully charged? Are you saying all four cells were fully discharged? Or, are you saying something else. Sorry, I really cannot understand.)

 

[LightX]

OK, so now I know how you will use these cells, so I can try to give you some more information. (I believe my information is correct, but others are more battery expert than I, so they may have different or better advice.)

So, first let's talk a little bit about what happens when you use 4x Eneelops together. (By the way, the LED Lenser P7.2 looks like a very nice flashlight!)

i havent really used since the first time i take it out of the packaging, maybe it has 3 cycles right now including the discharge > refresh and analyze. im planning to discharge it again to test if cell A has a stored capacity of 887mah

Your four cells: A, B, C, D each put out about 1.2v and I assume they are connected in series so total voltage is 4.8v to power the LED emitter. In the beginning, all four cells have plenty of energy (mAh), but as you use them, both their voltage and mAh is reduced. The problem may occur when one cell ("A") loses all of its energy before the other three cells. If energy of cell "A" goes to zero (completely dead) then the other three cells ("B," "C," and "D") may work together to "reverse charge" the cell "A."

Such "reverse charging" is very bad. In some rechargeable cells (like Li-Ion) or even some non-rechargeable cells (like CR123A) this can result in intense heat, release of poisonous gases, and even explosion. In the case of NiMH rechargeable cells (Eneloop) there are no safety risks that I know of. (I do not believe your Eneloop cells can ever explode.) But, I believe that such "reverse charging" can damage or destroy your Eneloop cell, so that you must replace it.


So, if you follow my description of the problem, then you can see that the simplest solution is to never drain all the energy from your "weakest" cell. In other words, if there is always enough energy (mAh) left in your cell "A," then your other cells will never try to "reverse charge" it. The benefit of matched cells (cells that contain as close as possible to the same amount of energy in each one) are that they can be safely drained down to "zero" or near "zero" (completely dead). In reality, this is usually only important in the "Hobby World" such as RC car racing. If you race RC cars, then having an excellent "matched" battery pack, can help you win races. But, for flashlights, I guess it is usually not so important.

-alright i get it, thats why they (manufacturer) are not allowing the consumer to use it with other types of battery or used battery as it may lead to reverse charging.. thats scary if that happens..

In fact, since voltage is also being reduced as energy is being reduced, I think there is good chance that your LED Lenser P7.2 may stop working (due to low voltage) before your cells can ever be completely drained. (I believe that this is a common feature/design of many good LED flashlights. But, I do not know enough about your flashlight to say whether or not this is true. But, I think it is likely.) In my case, I worry a bit more about having "matched sets" because I use many of my AAA Eneloops in very cheap "emergency" flashlights which probably do not have such complex circuitry, so I believe that they can probably use all the energy down to zero (LED just gets dimmer, and dimmer... as the voltage gets lower and lower.)

So, for now, my suggestion is to use your Eneloops in your flashlight, but recharge them before they are fully drained. (I believe your flashlight gets about 4 hours run-time on regular high mode, and 2 hours run-time on "boost" mode. So, try using it for only about 3 hrs. on high, or about 1.5 hrs on "boost.") Don't worry, this is not a permanent restriction. It is just my recommendation while you attempt to break in your troublesome cell "A."

I believe that my led lenser is not regulated, i noticed the brightness gets dimmer and dimmer after a long use.. i change batteries when the brightness is very low that i can look in the led directly.. ok thanks for the tip.. =)

When you remove your cells from your flashlight, fully discharge them in your MH-C9000. Your MAHA will drain all four cells "completely" (or down to the "best" level), but this is "safe" because your MAHA is treating each cell differently in its own individual circuit. That is why you noticed above that your cell "A" stops charging a long time before the cell "B." It has less capacity, so it takes less time to charge. This is completely normal.

which is the best? fully discharge or partial discharge? what's their advantage?
will my 4 batteries have the same level of voltage after i discharge it in my maha c9000?
after "done'' flashes, does it continue to discharge until it is completely drained or it just stops?
by the way what is internal resistance how did it affect the battery?
sorry for the flood question.. =)

But, hopefully, as you use your cells in your flashlight this way, you will begin to notice that the capacity of cell "A" begins to improve each time you recharge it.


If it does not begin to improve, then eventually you may wish to try the time consuming "BREAK-IN" procedure, or perhaps even multiple "CYCLE" procedure. But, I understood from your posting, that you wished to avoid such time consuming procedures, and enjoy your LED Lenser P7.2 immediately. So that is why I suggest just using your cell for a while, and see what happens. (It should be no problem at all to use your cell "A," so long as you do not "over-discharge" it while connected to the other three cells, as I explained above.)

if no improvement happens after refresh analyze, ill just do the break in procedure..

 

[LightX]

I guess anything is possible, but I think it is much more likely that your cell "A" just happens to (temporarily?) have lower capacity than your other three cells.


However, you should (of course) mark cell "A" in some way, so that you can keep track of its behavior from now on. Also, you can also watch "slot 1" of your MH-C9000 to see if it behaves in any abnormal or inconsistent way (in comparison with the other three slots).


Of course, you should try putting cell "A" in a different slot next time. If it charges normally in a different slot, and this time some other cell such a "C" which happens to be in "slot 1" charges poorly, this might indicate something unusual is going on with your MAHA.

im hoping that it is just temporary.
i already mark the cell A and now im planning to switch cell A and cell C to see if slot 1 is faulty
i hope not the charger (sigh)

 

[LightX]

I do not understand this part of your post. Can you explain in more detail exactly what you did? If you placed the cell into your 4xAAA flashlght, please explain the condition of each cell when you did so.

(Are you saying cell "A" was fully discharged by your MH-C9000 and placed into your 4xAAA flashlight, while the other three cells "B," "C," and "D" were still fully charged? Are you saying all four cells were fully discharged? Or, are you saying something else. Sorry, I really cannot understand.)

oh sorry, i put it in my flashlight after i fully discharged all 4 cells using maha c9000

 

[Rosoku Chikara]

oh sorry, i put it in my flashlight after i fully discharged all 4 cells using maha c9000

Ok, I think I now I understand about your "test." And, this is what your "test" means, in my opinion. You were surprised that your flashlight still showed light, even after all four cells were fully discharged using your MAHA. This is because your MAHA will only discharge your Eneloop cells down to their "safe" (recommended) voltage. For longest life (the most years of use, and largest number of recharge cycles), I think it is best not to discharge your cells to a level any lower than this "safe" voltage.

Therefore, the brightness level you see in your P7.2 with cells "fully discharged" by your MAHA, should be the lowest level you should ever consider using your flashlight down to. It is better to recharge your Eneloops before that low level is reached (or at least, before it is exceeded). Of course, in an "emergency" you can use your flashlight down as low as you need, but I think it is best not to do this on a regular basis.

Don't get too "crazy" about your MAHA charger/analyzer and caring about your Eneloop cells. It should be a fun hobby, not some cause for stress or worry. Remember, after all, they are only flashlight batteries. If you need to use your flashlight, use it the way you need to use it.

 

[Rosoku Chikara]

im hoping that it is just temporary.
i already mark the cell A and now im planning to switch cell A and cell C to see if slot 1 is faulty
i hope not the charger (sigh)

It "could" be the charger, but I doubt it very much.

Almost certainly, you just happen to have one "weak" cell. And, I think it may improve. Even if it doesn't, please keep in mind that the difference between your cell "A" and the average capacity of your other three cells, is only about 39 mAh. (With your flashlight in high mode, this means only about 5 minutes less runtime.)

I do, however, I think I understand your feeling about this matter very well. I too often seek "perfection" in my equipment and I am troubled when sometimes things do not work out in the best possible way. It can be frustrating, but don't worry too much. As I mentioned above, after all, it is only a flashlight battery.

 

[Rosoku Chikara]

<snip>...which is the best? fully discharge or partial discharge? what's their advantage?...

"Fully discharged" by your MAHA MH-C9000 is "OK" (safe), because the charger is designed not to over-discharge your Eneloops below the recommended level. (So, in this case your cells are not being trul "fully discharged" only partially discharged down to the safe level.)

"Fully discharged" in your flashlight, or other device, can be "bad" and may damage your cells (especially when multiple cells are used in series because of the risk of "reverse charging" which I mentioned in a previous post).

In the past, rechargeable cells (especially NiCAD) were often said to have a "memory effect," which required fully discharging them each time. This probably never was as important as most people thought, and it is certainly not important any more with NiMH.

As you use your Eneloops for a year or more (maybe 50-100 cycles?) you may notice some decrease in capacity. (You could notice such decrease sooner, but it is unlikely, I think.) If you notice such decrease in capacity, I would run "BREAK-IN" procedure to recondition the cells. If you don't notice any decrease in capacity, I think you can simply keep using them normally. (I guess it means that your normal usage is keeping your cells in "happy" condition.)

<snip>...after "done'' flashes, does it continue to discharge until it is completely drained or it just stops?...

I am not the expert on MH-C9000 circuitry, but I think the "DISCHARGE" procedure just stops when the display flashes "DONE." (I can think of no logical reason to design the circuity to continue to drain longer. This is completely different from "CHARGE" which continues to trickle charge for 2 hours.)

<snip>...by the way what is internal resistance how did it affect the battery?...

So, now you are asking questions which I have no confidence to answer. I do not know much about internal resistance, even after all my studying on this forum for the past year. I have read that the MAHA MH-C9000 will flash some voltage number, for a very brief moment, and only once, when your first set a cell for the "CHARGE" procedure. I have heard that this voltage number has some relationship to internal resistance.

I do not believe that there is any mention of the above "internal resistance" measurement in the MAHA manual, but it makes sense, because if the cell has too high of internal resistance, the MAHA will display the word "HIGH" and refuse to charge that cell. Therefore, the MAHA must be somehow checking the internal resistance when the cell is first inserted.

For details on how to measure internal resistance please see this info by HKJ:

http://lygte-info.dk/info/Internal impedance UK.html

As you may have already seen from his posts, HKJ is one of the best battery/charger experts on this forum.

Here is a link to a thread about internal resistance:

http://www.candlepowerforums.com/vb...Can-someone-Explain-to-me-Internal-Resistance

 

[LightX]

Ok, I think I now I understand about your "test." And, this is what your "test" means, in my opinion. You were surprised that your flashlight still showed light, even after all four cells were fully discharged using your MAHA. This is because your MAHA will only discharge your Eneloop cells down to their "safe" (recommended) voltage. For longest life (the most years of use, and largest number of recharge cycles), I think it is best not to discharge your cells to a level any lower than this "safe" voltage.

Therefore, the brightness level you see in your P7.2 with cells "fully discharged" by your MAHA, should be the lowest level you should ever consider using your flashlight down to. It is better to recharge your Eneloops before that low level is reached (or at least, before it is exceeded). Of course, in an "emergency" you can use your flashlight down as low as you need, but I think it is best not to do this on a regular basis.

Don't get too "crazy" about your MAHA charger/analyzer and caring about your Eneloop cells. It should be a fun hobby, not some cause for stress or worry. Remember, after all, they are only flashlight batteries. If you need to use your flashlight, use it the way you need to use it.

I think its 0.9 v i noticed it when im watching the charger to to finish discharging. How low could possibly a cell can discharge? I want to know how high the "safe" voltage is, compared to fully discharge.. If my cells are fully discharge my c9000 will still charge it right?

 

[LightX]

It "could" be the charger, but I doubt it very much.

Almost certainly, you just happen to have one "weak" cell. And, I think it may improve. Even if it doesn't, please keep in mind that the difference between your cell "A" and the average capacity of your other three cells, is only about 39 mAh. (With your flashlight in high mode, this means only about 5 minutes less runtime.)

I do, however, I think I understand your feeling about this matter very well. I too often seek "perfection" in my equipment and I am troubled when sometimes things do not work out in the best possible way. It can be frustrating, but don't worry too much. As I mentioned above, after all, it is only a flashlight battery.

Hi i found some thread regarding my problem in slot 1
here's the link: http://www.candlepowerforums.com/vb...charging-evenly-compared-to-the-other-3-slots
i have the same problem like that, he said that the charger has been replaced and also bought new one but the slot 1 problem still exist so maybe it is not a defect but temperature issue.. Someone also emailed maha and maha support explained it. What do you think should i do, if it is not considered a defect? I really bothers me.. I don't really want to have a least performing slot..

by the way i'm running break in mode but still charging haha! I think ill break in all my cells after i see the result in dischrarge

slot 1 959 cell d
slot 2 952 cell c
slot 3 944 cell b
slot 4 952 cell a

after this should i run discharge > refresh and analyze? Will the result improve more if i do it? Thanks!

 

[LightX]

"Fully discharged" by your MAHA MH-C9000 is "OK" (safe), because the charger is designed not to over-discharge your Eneloops below the recommended level. (So, in this case your cells are not being trul "fully discharged" only partially discharged down to the safe level.)

"Fully discharged" in your flashlight, or other device, can be "bad" and may damage your cells (especially when multiple cells are used in series because of the risk of "reverse charging" which I mentioned in a previous post).

In the past, rechargeable cells (especially NiCAD) were often said to have a "memory effect," which required fully discharging them each time. This probably never was as important as most people thought, and it is certainly not important any more with NiMH.

As you use your Eneloops for a year or more (maybe 50-100 cycles?) you may notice some decrease in capacity. (You could notice such decrease sooner, but it is unlikely, I think.) If you notice such decrease in capacity, I would run "BREAK-IN" procedure to recondition the cells. If you don't notice any decrease in capacity, I think you can simply keep using them normally. (I guess it means that your normal usage is keeping your cells in "happy" condition.)



I am not the expert on MH-C9000 circuitry, but I think the "DISCHARGE" procedure just stops when the display flashes "DONE." (I can think of no logical reason to design the circuity to continue to drain longer. This is completely different from "CHARGE" which continues to trickle charge for 2 hours.)



So, now you are asking questions which I have no confidence to answer. I do not know much about internal resistance, even after all my studying on this forum for the past year. I have read that the MAHA MH-C9000 will flash some voltage number, for a very brief moment, and only once, when your first set a cell for the "CHARGE" procedure. I have heard that this voltage number has some relationship to internal resistance.

I do not believe that there is any mention of the above "internal resistance" measurement in the MAHA manual, but it makes sense, because if the cell has too high of internal resistance, the MAHA will display the word "HIGH" and refuse to charge that cell. Therefore, the MAHA must be somehow checking the internal resistance when the cell is first inserted.

For details on how to measure internal resistance please see this info by HKJ:

http://lygte-info.dk/info/Internal%20impedance%20UK.html

As you may have already seen from his posts, HKJ is one of the best battery/charger experts on this forum.

Here is a link to a thread about internal resistance:

http://www.candlepowerforums.com/vb...Can-someone-Explain-to-me-Internal-Resistance

ok thanks for some tips and the link..
Please correct me if im wrong..
When charging finishes, "done" will appear right? after that it will switch to 100 ma for 2 hours then switch to 10 ma for maintenance?

Thanks! &#55357;&#56835;

 

[Rosoku Chikara]

<snip>...When charging finishes, "done" will appear right? after that it will switch to 100 ma for 2 hours then switch to 10 ma for maintenance?...

I don't remember in that much detail about my MAHA anymore, so I would have to check the forum to find the details again, but I think you are correct. I am sure about the 100 mA for 2 hrs, and the 10 mA for "maintenance" also sounds correct.

But, to tell you the truth, I don't pay that much attention anymore. I guess that usually more than 2 hrs have passed by the time I notice the charger says "DONE." So, I guess most of the time I get the "extra" 100 mA charge. But, I don't think it is that important. I just remove the cells when I notice "DONE."

As far as maintenance charge of 10 mA, I would say that it has no meaning in the case of LSD cells like Eneloop. They do not need any maintenance charge because they hold their charge so well.

 

[Rosoku Chikara]

<snip>...after this should i run discharge > refresh and analyze?

I cannot answer this question. In my case, when I read the manual, I understood that "refresh and analyze" is best for accurate measurement of cell capacity. So, decided to make another DISCHARGE after BREAK-IN and then run REFRESH/ANALYZE. But, now I think that maybe BREAK-IN may provide more accurate capacity measurement. (I read that this kind of "16 hours at 0.1 C" method, is the method used for international standards on battery measurement.) So, I cannot really advise you.

In your case, I believe you should be most concerned about getting consistent capacity results across all four of your cells. In other words, what ever the capacity measured, you want the capacity of your "weak" cell (cell "A") to be similar in capacity to your other cells.

So, if you feel your measurements are still inconsistent, and you want to keep trying, you can try REFRESH/ANALYZE. There is also CYCLE procedure, although I have never used it yet. With CYCLE you make same programing of charge rate and discharge rate like REFRESH/ANALYZE, but then repeat procedure many cycles. (You can decide how many cycles to repeat.) I do not believe that this is necessary, I think it is better to just use your weak cell, if indeed it is still weak.

Remember, Eneloop XX is rated for 500 cycles, but this could mean "only" 200-300 cycles (or less?) in real life, depending on how you use (or abuse) them. Personally, I do not see any real problem, because I do not recharge my Eneloop Pros that often. So, even "only" 200-300 cycles is many years usage for me. But, remember that each MAHA procedure such as REFRESH/ANALYZE is taking some life out of the total life of your cell.

<snip>...Will the result improve more if i do it?

Once again, there is no way for me to know what will happen with your weak cell. It may improve, it may not. In my case, as I showed in many examples in my post of 12-13-2013 above, I find that C gives slightly lower mAh capacity number than BREAK-IN. In the case of a weak cell, I think any kind of cycling (normal use, BREAK-IN, REFRESH/ANALYZE, or CYCLE) may help "strengthen" it due to a kind of "exercise." But, there is no certain way to know for sure if such "exercise" will help or not.

So, as I wrote above, you should balance your "exercise" so that you do not lessen the total life of your cell too much, with just exercise. It is better to just use the cell as it is.

Anyway, I am hoping that the capacity reading of your cell "A" will be improved at the end of the BREAK-IN cycle. Good luck!

 

[Rosoku Chikara]

I think its 0.9 v i noticed it when im watching the charger to to finish discharging. How low could possibly a cell can discharge? I want to know how high the "safe" voltage is, compared to fully discharge.. If my cells are fully discharge my c9000 will still charge it right?

If you somehow damage your cell, or as your cell grows "old" naturally, then eventually the internal resistance will become too high, and your C9000 will refuse to charge it anymore. (The display will say "HIGH.") Some people have tried to "fix" these cells, and keep using them. But, it seems best to "recycle" your cell (dispose of properly) once this point is reached. (Of course, if you see this "HIGH" reading on some cells which are not very old, and should not be damaged yet, then it could mean something has gone wrong with your MAHA charger, so please use your common sense. But, if you have been using your cells for many years, or somehow "abusing" them, you should know by feeling whether or not it is the reasonable time to replace your old cells with new ones. So, in that case, you should follow the MAHA's advice when it says too "HIGH.")

As I mentioned in an earlier post above, you should try not to over discharge your cells below the "safe" (recommended) voltage. I haven't paid much attention lately, but I guess that you are correct when you say 0.9v on the MAHA discharge. So, this is probably the best discharge level for NiMH chemistry. Try not to go below that. If you do go below, I do not think your cells will be immediately destroyed, and your MAHA should still charge them with no problems. But, I think over-discharging is a kind of "abuse," so the more often you do it, the shorter the life of your cells are likely to be.

As also already mentioned above, you must be much more careful when using 4x cells in series. In that case, discharging to a level below the weakest cell can result in "reverse charging" which I believe is much worse than simple over-discharging. I think "reverse charging" can possibly destroy (or seriously damage) your cell almost immediately, but it depends on the exact circumstances.

Sorry, but your questions are getting much more detailed, and they are fast exceeding my understanding. I believe everything I am writing here is true, but there are many others on this forum with much more precise knowledge about over-discharging, and reverse charging and its damaging effects on cell chemistry. If you really want to know the detailed answers, you should post a specific question, and wait for their reply. But, the simplest rule to understand (and follow) is: be "nice" to your Eneloops and they will be "nice" to you.

 

[LightX]

Alright maybe that will be it.. Thanks a lot Rosoku Chikara.. I learned a lot from you..