# Maha C9000 Break-In Mode



## TheWalkman (Mar 9, 2007)

Here's an item for discussion: I just received my upgraded C9000 and a couple of new sets of Powerex AAA (1000MAH) batteries. 

What's the optimal method to break them in?

(Thomas Dist. recommended cycling three times and discharging before using the break-in mode. What are your thoughts on charge and discharge rates for cycling? 1C - 1C; 1C - .5C?; .5C - .5C)

Opinions? It seems like the C9000 is generating a lot of these!
:touche:


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## sylvainp (Mar 9, 2007)

Your cells are new.

Here are my recommendation:

1) Break-in (use Mah rated value of your cells: 1000 mah in your case)
2) Do a cycle with charge rate (500 ma) and discharge rate (200 ma) for 3 cycles.

After that your cells should be OK and in good shape !


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## SilverFox (Mar 9, 2007)

Hello TheWalkman,

You have several options...

You can put your cells in the charger and, using the default charge rate, charge them up and use them.

If you want to get a jump on conditioning them, you can do a 500 mA discharge, then follow it with a 1000 mA charge, then use them.

You will find that as you use them, there may be some improvement over the first few cycles.

Now, if you want to do a full conditioning before using them, you have two options.

You can run 5 or 10 cycles using 1000 mA as a charge rate, and 500 mA as a discharge rate. You should notice an improvement in capacity over the first few cycles, and then it should stabilize.

Your second option is to do a 500 mA discharge on them, followed by a Break-In cycle.

Tom


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## di.corp (Mar 9, 2007)

SilverFox.. of those last two alternative you just gave.. which one would you recommend..?? I too got a brand new C9000 of the new model.. and are going to order some PowerEx and Eneloop AAA and AA batteries..


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## SilverFox (Mar 9, 2007)

Hello Di.corp,

Welcome to CPF.

I do a discharge, followed by the Break-In mode.

This gives me a baseline capacity to judge future cell condition to.

Tom


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## di.corp (Mar 9, 2007)

thanks for the warm welcoming.. =) 

thanks for the tips.. that is good to know.. want to have the best start I can get with my new cells.. here in Sweden the cheapest Eneloop AA is around $9.5 and for that money you only get 2 cells..


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## Boss Hogg (Aug 5, 2010)

With the break-in mode I see that the default setting is 2,500 mAH. Does this have to be properly set? I'm using the somewhat mysterious ROV 4.0 NiMH that does not have any mention of its capacity on the package and wondering what mAH I have to set it at.


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## InHisName (Aug 5, 2010)

I have some AAA ROV 4.0s and they come close to 800Mah. I would expect the AAs to be near 2000Mah. So that should be a pretty good guess.


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## WildChild (Aug 5, 2010)

Boss Hogg said:


> With the break-in mode I see that the default setting is 2,500 mAH. Does this have to be properly set? I'm using the somewhat mysterious ROV 4.0 NiMH that does not have any mention of its capacity on the package and wondering what mAH I have to set it at.



You can do a Refresh/Analyze cycle first to know the capacity. With the break-in mode, you choose the capacity so the charger sets the current for a timed 16h charge (C/10). You have to know the rated capacity or the cell will be either overcharged or undercharged.


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## Sparkss (Aug 5, 2010)

What about batteries with a XX50 (like 2450) capacity ? since the C-9000 uses 100 Mah increments. I had been setting it to 2400 to play it safe, but is it better to set it to 2500 ?


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## cckw (Aug 5, 2010)

Boss Hogg said:


> With the break-in mode I see that the default setting is 2,500 mAH. Does this have to be properly set? I'm using the somewhat mysterious ROV 4.0 NiMH that does not have any mention of its capacity on the package and wondering what mAH I have to set it at.



it is default only because they had to start somewhere. you need to know the capisity of your batteries and use that number. Eneloops for example are 2000. it commonly says on the battery. If you don't know then post in this thread what you have someone may know.


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## SilverFox (Aug 6, 2010)

Hello Sparkss,

The decision to round up or round down depends on how close the labeled capacity matches the actual capacity. Most of the time it seems that the label is optimistic, which would indicate rounding down.

The charge rate is low enough that either way you go the cell will not be damaged. If you want to run a test on this, do a break in rounding down, then do another rounding up and see what difference there is.

Tom


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## fishinfool (Aug 6, 2010)

SilverFox said:


> The charge rate is low enough that either way you go the cell will not be damaged. If you want to run a test on this, do a break in rounding down, then do another rounding up and see what difference there is.
> 
> Tom


 
That's interesting. I think I'll experiment on 4 of my new eneloop tones and break them in at 2000mah instead of 1900mah. Maybe I'll just keep going higher maybe up to 2500mah and see what happens.  

I'll start at 2000mah first and see what happens. :duck:


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## Mr Happy (Aug 6, 2010)

fishinfool said:


> That's interesting. I think I'll experiment on 4 of my new eneloop tones and break them in at 2000mah instead of 1900mah. Maybe I'll just keep going higher maybe up to 2500mah and see what happens.


I wouldn't, personally. A break-in cycle does cause wear on the cells, and the higher the current you use the more wear.

It's like exercise. Exercise is good for you, but the harder and more often you exercise the more risk of injury and wear and tear on your joints. For the normal person you should exercise in moderation and don't go crazy about it.


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## Boss Hogg (Aug 7, 2010)

cckw said:


> it is default only because they had to start somewhere. you need to know the capisity of your batteries and use that number. Eneloops for example are 2000. it commonly says on the battery. If you don't know then post in this thread what you have someone may know.



Rayovac 4.0 NiMH.


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## fishinfool (Aug 7, 2010)

Mr Happy said:


> I wouldn't, personally. A break-in cycle does cause wear on the cells, and the higher the current you use the more wear.
> 
> It's like exercise. Exercise is good for you, but the harder and more often you exercise the more risk of injury and wear and tear on your joints. For the normal person you should exercise in moderation and don't go crazy about it.


 
I won't do it with any of my new cells but I'll probably try it out on some older ones just to see what happens. I have a few 7-8 yr. old Team Orion 1800 mah nimh batteries from my rc nitro days that I can experiment with. I'm thinking about breaking them in at 2000mah. Just thinking about it though. :thinking:


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## SilverFox (Aug 8, 2010)

Hello Fishinfool,

A key item with testing like this is to monitor the cell temperature. If the temperature increases, the exercise is getting harder.

Tom


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## fishinfool (Aug 8, 2010)

SilverFox said:


> Hello Fishinfool,
> 
> A key item with testing like this is to monitor the cell temperature. If the temperature increases, the exercise is getting harder.
> 
> Tom


 
Thanks Tom. One thing I've learned from CPF is that heat is bad for batteries so when I started investing in batteries and chargers I made sure to buy an extra electric fan just for my battery station. I also bought an infrared thermometer just to check on the batteries as they are being charged. 

I know it sounds like I've gone overboard with all this extra stuff but I value everything I buy and would want them to last as long as possible. Now that made me sound cheap but that's ok because I am cheap.


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## cckw (Aug 8, 2010)

Boss Hogg said:


> Rayovac 4.0 NiMH.




rayovac 4.0 is a 2000 mah rated battery


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## gt_mule (Aug 15, 2010)

I'm doing an initial break-in cycle on new eneloop 1900mAh aa cells. About 30 hours has elapsed. I programmed the Maha C9000 with the correct capacity for each cell. I am watching them charge and now each one is above 2400mAh. Is this normal?


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## constipated (Aug 15, 2010)

Yes, Break-in mode charges at 0.1C for 16 hours so should put in 200 x 16 = 3200 mAh.


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## Battery Guy (Aug 15, 2010)

fishinfool said:


> Thanks Tom. One thing I've learned from CPF is that heat is bad for batteries so when I started investing in batteries and chargers I made sure to buy an extra electric fan just for my battery station. I also bought an infrared thermometer just to check on the batteries as they are being charged.



You are correct that heat is the enemy of batteries. However, with respect to charging of NiMH cells, you actually depend upon a temperature rise.

For NiMH cells, active cooling during charging can be a bad idea for the following reasons:

1.) Most smart chargers use a -dV measurement for charge termination. The reason that the voltage drops at "top of charge" is because the cell starts to warm because heat is generated by oxygen recombination. If you actively cool the cell, the voltage may not drop, the charger may not terminate, and the cell will be damaged.

2.) As mentioned above, when the cell reaches top of charge, oxygen is generated at the positive electrode and must be recombined at the negative electrode. If the rate of oxygen recombination is less than the rate of oxygen generation, the cell will build up pressure and vent. Cooling the cell reduces the rate of oxygen recombination, and therefore more susceptible to pressure build up.

An extreme example of this would be attempting to fast charge a NiMH cell in an ice water bath. Most of the charge current will go into the generation of oxygen, which will not recombine at the negative electrode due to the low temperature. The result will be venting of the generated oxygen and loss of electrolyte.

So Fishinfool, your idea is sound, and if carefully controlled, cooling cells during charge could indeed reducing degradation. However, be aware that you are walking a fine line here, and that if you extract too much heat with your cooling fan, you could substantially damage your cells during charge.

My advice is to let your cell heat up during charge, and then do your best to keep them cool during storage and use.

Cheers,
BG


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## MarioJP (Aug 15, 2010)

I guess it also depends on the charger you are using. Some chargers just seems to radiate heat into the batteries and that can be bad for the cells too. At least get a charger where the heat does not migrate to the batteries.

With some chargers you have no choice but to use a cooling fan if you don't want your cells to be roasted from external heat during charging , especially if you going to be experimenting with bad cells.

Not to go of topic on this thread but going back to cooling your cells when using cooling fan. Interesting thing about this is that sometimes its ineffective. 

For what I have seen so far, all it does it prevents the cells from becoming too hot, but they will still warm up. Also doesn't seem to effect the -dv that much, only delays by a tad bit. I did notice extra mAh gains on the cells too. Seems to top them off easily.

I also read that heat reduces the charge efficiency too. I only started doing this with my eneloops as they got a bit too hot when fast charging. That excessive heat has got to go!.


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## fishinfool (Aug 16, 2010)

Battery Guy said:


> You are correct that heat is the enemy of batteries. However, with respect to charging of NiMH cells, you actually depend upon a temperature rise.
> 
> For NiMH cells, active cooling during charging can be a bad idea for the following reasons:
> 
> ...


 
Thanks BG. I never thought that cooling batteries while charging or even discharging could be a bad thing but now that you mentioned it, I now keep the fan on the lowest setting and a few feet away from the charging station. Since I do live in Hawaii where it's always hot and humid (high 70's, low to mid 80's), keeping a fan on low a few feet away shouldn't hurt too much. *Should it?*

I checked on a batch of batteries earlier and even with the fan on low, the batteries were in the high 80's (fahrenheit). 

*BTW, how much heat is too much for charging or discharging batteries? *

*Thank you!*


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## Battery Guy (Aug 16, 2010)

MarioJP said:


> I guess it also depends on the charger you are using. Some chargers just seems to radiate heat into the batteries and that can be bad for the cells too. At least get a charger where the heat does not migrate to the batteries.



Hi Mario

This is a very good point, and something that I did not consider. You certainly don't want to be heating the cells from an external source. While this will help to prevent venting and leakage due to inadequate oxygen recombination, your charge efficiency may be decreased and the cells may not reach top of charge.

Thanks for pointing this out!

Cheers,
BG


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## Battery Guy (Aug 16, 2010)

fishinfool said:


> Thanks BG. I never thought that cooling batteries while charging or even discharging could be a bad thing but now that you mentioned it, I now keep the fan on the lowest setting and a few feet away from the charging station. Since I do live in Hawaii where it's always hot and humid (high 70's, low to mid 80's), keeping a fan on low a few feet away shouldn't hurt too much. *Should it?*
> 
> I checked on a batch of batteries earlier and even with the fan on low, the batteries were in the high 80's (fahrenheit).
> 
> ...



Mario brought up a good point in the post above yours about eliminating heat from external sources.

Bottom line is that if you are charging fast enough to terminate charge based on a -dV measurement, there is a temperature window that you want to be in. Too low of a temperature and the internal pressure will build up and the cell will vent. Too high and the cell may be damaged and might not be at top of charge when termination occurs.

I just want to point out that keep a NiMH cell cool during charge is not necessarily a good thing, and in the extreme, can certainly result in damage to the cell.

My philosophy has always been to assume that the cell and charger designers know what they are doing, and to leave the system alone. However, if you think that the cells are getting too hot during charge (too hot would be >60 degrees C, and feel very uncomfortable to hold), then I would recommend charging at a lower rate. 

Hope this helps to clarify.

Cheers,
BG


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## fishinfool (Aug 16, 2010)

*Thanks guys!* :wave:

Right now, my last 4 appleloops are at the end of a break-in cycle and they are around 101*F. This is with the fan a few feet away and on the lowest setting. It's been in the 80's almost everyday for months now. :sweat:


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## MarioJP (Aug 16, 2010)

hmmm. This made me want to put this theory to the test. Gotta love the mythbuster show 

So far I only done this on fast charges and not slow charges. I do know that even with the fan blowing at the cells when charging at a high rate the cells warm up when its nearing at the end of their charge cycle, and also when they are done the cells are warm to the touch regardless of the fan blowing at them.

I guess that also explains the extra mah gained. Just bragging rights gained, not by much lol.

In fact I am doing a test capacity to see how these cells are performing. I don't break them in as the application i use these cells drains them below 0.90v anyways lol. Test capacity once a month is ok i guess.


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## fishinfool (Aug 16, 2010)

MarioJP said:


> hmmm. This made me want to put this theory to the test. Gotta love the mythbuster show
> 
> So far I only done this on fast charges and not slow charges. I do know that even with the fan blowing at the cells when charging at a high rate the cells warm up when its nearing at the end of their charge cycle, and also when they are done the cells are warm to the touch regardless of the fan blowing at them.
> 
> ...


 
I'm anxiously waiting for the test results.


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## Bones (Aug 16, 2010)

fishinfool said:


> I'm anxiously waiting for the test results.



You and MarioJP may be inadvertently comparing the proverbial apples and oranges.

I believe that he utilizes a LaCrosse BC-9009, which is an entirely different charger than the MH-C9000.

The BC-9009 is considerably more compact, with much more tightly spaced charging bays, so it will always impart significantly more heat to the cells it's charging, especially at it's maximum rate of 1000mA.

As well, unlike the BC-9009, which actually does rely primarily on -dV to terminate its charge, the MH-C9000 relies on an algorithm that employs peak voltage as it primary termination indicator.

Accordingly, as long as the cells being charged in the MH-C9000 can reach approximately 1.47V, it will terminate properly. It only relies on -dV to terminate its charge with cells that can't reach this voltage.

Knowing this, I make it a habit to monitor cells that I've never before charged in the MH-C9000 to ensure they can reach 1.47 volts during the primary charge. I then charge those that can't at a rate intended to maximize the -dV voltage drop.

This thread now has me wondering what effect, if any, forced cooling would have on the behavior of the MH-C9000 considering it's different primary termination methodology.


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## MarioJP (Aug 17, 2010)

Bones said:


> You and MarioJP may be inadvertently comparing the proverbial apples and oranges.
> 
> I believe that he utilizes a LaCrosse BC-9009, which is an entirely different charger than the MH-C9000.
> 
> ...



Good points bones. And to clarify things here. I do not have appleloops, though tryingg to figure what apple has done different that makes these cells "magical". I have to handed to apple on their marketing department. Wow what a sales pitch sure could of fooled me lol.


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## Battery Guy (Aug 17, 2010)

Greetings All

I am beginning to think that my rambling posts have caused some confusion. I will attempt to clarify. Here are the key points:

1.) The reason that you see a peak in the voltage of a NiMH, followed by a voltage drop, during charge is that the cell temperature rises. 

2.) This rise in cell temperature reduces the internal resistance, causing the observed drop in voltage. 

3.) The rise in cell temperature at the end of charge is the result of oxygen generation and recombination within the cell.

4.) The rate of oxygen generation is proportional to the charge current. The rate of oxygen recombination is dependent upon many factors, but increases with increasing temperature.

5.) The rate of oxygen recombination must equal or exceed the rate of oxygen generation, otherwise internal pressure will build up and the cell will vent.

So, if you are successful at keeping your cells cool during charge, the following things may happen:

1.) There will be no peak in the voltage because there will be no rise in temperature, resulting in no charge termination in chargers that look for a peak.

2.) The oxygen recombination rate may be insufficient to keep up with the rate of oxygen generation, resulting in venting of the cell.

Now, I don't necessarily think that blowing a fan on your charger is going to be sufficient to cause damage. If you want to put a fan on your charger to remove excess heat from the charger itself and keep the cells a few degrees cooler, I don't see a problem with this. 

However, with a group of clever, innovative people like those that read CPF, I worry that someone is going to take this to the extreme and design a glycol-cooled heat extraction system for their MH-C9000. That would not be wise.

I hope this helps to clarify the issue around cooling NiMH cells during charge.

Cheers,
BG


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## MarioJP (Aug 17, 2010)

I guess that's the downside of compact chargers. Heat migration to the cells easily, although not all compact chargers have this problem. I think the reason for the la crosse heating the cells is due to the charging circuitry is underneath the bays.That's where most of the heat is coming from.

I also have a compact Duracell wall wart charger, which most here have heard of has a usb port on it. Problem with this charger is the power transformer is right next to the 2 bays at the end causing 2 out of 4 cells to get quite hot while the other 2 are warm. I rotate the cells because of this.

If its going to heat the cells up heat them evenly at least lol.

I also think the C9000 has the charging circuitry away from the bays also helps keeping external heat away from the cells, sides being spacious between the cells. Correct me if I am wrong on that one.


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## mailer (Jan 10, 2016)

Hello. I have a question about break-in mode. I buy 4 new sets of 8xAA batteries with 2300 mAh capacity, LSD ready for use. 
At first I use discharge function with 300mA for all of them. Then I use break-in function and set the capacity to 2300mAh. 
5 sets were charged OK (16h charge, rest, discharge, rest, 16h charge) and on lcd sign "DONE" was on.
3 sets have the same cycle, but the time on the end of break-in was around 330min +-10 min. (usually the second charge time shoud be 960 min) 
Did anyone have the sam issue?
P.S. The sign "DONE" was also on.


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## kreisl (Jan 10, 2016)

how old is your charger?


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## mailer (Jan 12, 2016)

A year and a half. Purchased and send from nkon.nl.


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