How do you "break-in" NiHM/Eneloop cells? Discharge first?

[gdillainepub]

Hi folks,

I have MAHA C9000 and SkyRC NC2500, both come with the break-in program (0.1C charging for 16 hours--> rest--> the 0.2C discharging -->rest-->0.1C charging for 16 hours again, then terminate).

Since this break-in procedure uses a 16 hour charge without regard of any commonly used termination signal (dV/dt, temperature, voltage limit, etc.) -- and only thing the charger uses is to (1) calculate 0.1C, (2) go on for 16 hours. Nothing else in the equation.

So I always think it will be different if the initial charge the battery has before it is put into the break-in is taken into account:

Scenario 1. If discharging the batteries first, the first 10 hours of the 16 hours would be the "normal" charge that gives the battery to its full capacity, and so there will be 6 hours left for the "superfluous" charge (i.e., the continued charging after the battery has been fed to its full capacity -- call it "superfluous", "redundant" or whatever, you know what I mean)

Scenario 2. However, if the battery is already fully charged when it is put into break-in, then it might take 1 hour to the top off the battery for the loss of charge during the storage, and the rest 15 hours will be "superfluous" charge.

Now you get what I'm talking about -- the time in the break-in where the battery was under "superfluous" charge may vary, depending on the initial charge it holds before it is put into break-in.

Therefore here is the question: How do you do the break-in if the time of "superfluous" charge is taken into consideration:

1. Discharge the battery and rest, before it undergoes break-in?

2. Fully charge the battery and rest, before putting it in for break-in?

3. Just put the battery as it is into the break-in -- the initial charge it has doesn't matter??

 

[CelticCross74]

I go exactly by the instructions on the back of the packs my Pros come in which is to charge the cells before use. Havnt read an Eneloop pack that says anything about discharging. Have a Maha 808 (I think thats it is the big 8 bay one that can take D's) and the outstanding Xtar VC4. The big Maha can fast charge my older Eneloops in 30 minutes kind of worries me they come off the charger pretty warm. With the Xtar I use the iPhone 6 upgrade wall wart USB charger to plug it into. Works better and faster than the 2.1 amper that came with it regardless even in that set up charging up a fresh set of Pros on it takes a couple of hours. I would just follow whatever instructions are printed on your Eneloop pack. Far as I knew the whole discharge/slow charge routine was for old cells.

 

[Learningtobeprepared]

Very interesting. I just ordered my first eneloops

 

[kreisl]

maha user manual quotes an IEC norm. i looked it up. the norm states that the battery needs to be discharged first.

i don't do break-in anymore, ive become lazy with keeping up things. but when i run break-in program in maha or 2500, i discharge first.

 

[Yamabushi]

New eneloops don't need break-in but if you want to do the Break-in cycle on a C9000, discharge the battery before running the Break-in cycle.

 

[MidnightDistortions]

New Eneloops and Eneloops in general don't really benefit much from a break-in. At least there hasn't been the need for it for me anyway. I have found the break-in's work wonders on traditional self discharge batteries and those that have fallen below capacity. With that being said, if i were to break-in an Eneloop cell or any other LSD cell i would first, regularly charge it (if it hasn't been charged in awhile) then run a discharge and then do the break-in (if needed). The break-in functionality helps traditional cells to properly terminate, if you have used as many traditional cells as i have, there's plenty that terminate well before they should. I have noticed that some cells become weaker if they are partially charged so if there is more than 30-40% capacity on traditional NiMH cells i would run a discharge on them first. Eneloops and other LSD batteries are best fully discharged before applying a break-in but most LSD cells i have found only need them when overall capacity is declining and weak.

 

[samgab]

New eneloops:
1: Remove from package.
2: Use.
3: Recharge.
4: Repeat (x 2100 or whatever it ends up being.)

 

[UnderPar]

New eneloops:
1: Remove from package.
2: Use.
3: Recharge.
4: Repeat (x 2100 or whatever it ends up being.)

Plus 1 to this. This is what I normally do to my Eneloops. Never heard of discharging it first. Out of the package, Its good to go..

 

[ven]

New eneloops:
1: Remove from package.
2: Use.
3: Recharge.
4: Repeat (x 2100 or whatever it ends up being.)

I remove,top up use and recharge /repeat, so almost the same :laughing:

 

[WalkIntoTheLight]

Yeah, as said, Eneloops don't require a break in. I have done tests, and the difference you get from doing a break-in, vs. just charging and using, is about 1%-2% extra capacity from a break-in. However, that benefit is only in the first 1 or 2 cycles. After you've used the Eneloops a couple of times, there will be no difference in capacity whether or not you did a first initial "break in".

So, don't bother.

 

[MidnightDistortions]

Plus 1 to this. This is what I normally do to my Eneloops. Never heard of discharging it first. Out of the package, Its good to go..

I'll run a test on them just to make sure but otherwise they work just fine out of the package.

 

[chuckhov]

Of course, all of this 'break in' talk implies that the cell has Memory, which is contrary to reports that NiMH does not have memory. (at least 'conventional' 'non LSD' NiMH)

???

I always charge mine first, but that says more about me than the cells, and I have no data.

Does anyone really know?

Thanks,
-Chuck

 

[PapaLumen]

I discharge first before a break-in.

 

[SilverFox]

I approach this from a little different perspective...

Usually I don't need the cells immediately, but if I did I would use Eneloop cells right out of the package.

I anticipate using these cells in multi cell applications. I have found that by matching the cells in these applications I get better performance.

Normally I will discharge the cells first, followed by a Break In. I make note of the capacity. This becomes my "benchmark" for when to retire the cell. I retire when the cell drops below 80% of this initial capacity.

The next step is to match the cells based upon normal charging and discharging conditions. With Eneloop cells I charge at 1000 mA and discharge at 500 mA and find that covers many of my applications.

Now I am ready to use the cells and know what I am working with.

Tom

 

[MidnightDistortions]

Of course, all of this 'break in' talk implies that the cell has Memory, which is contrary to reports that NiMH does not have memory. (at least 'conventional' 'non LSD' NiMH)

???

I always charge mine first, but that says more about me than the cells, and I have no data.

Does anyone really know?

Thanks,
-Chuck

NiMH cells can become chemically deactivated, https://static.eleshop.nl/mage/user-manuals/mh-c9000-manual-en.pdf

which a break-in can restore NiMH cells to proper specs. Most of the reasons to discharge a NiMH cell fully is to work the cell and it also helps in case the cell has been slightly overcharged. NiMH cells can have voltage depression for those reasons, they'll underperform and you won't get a good run time out of them.

 

[KeepingItLight]

I approach this from a little different perspective...

Usually I don't need the cells immediately, but if I did I would use Eneloop cells right out of the package.

I anticipate using these cells in multi cell applications. I have found that by matching the cells in these applications I get better performance.

Normally I will discharge the cells first, followed by a Break In. I make note of the capacity. This becomes my "benchmark" for when to retire the cell. I retire when the cell drops below 80% of this initial capacity.

The next step is to match the cells based upon normal charging and discharging conditions. With Eneloop cells I charge at 1000 mA and discharge at 500 mA and find that covers many of my applications.

Now I am ready to use the cells and know what I am working with.

Tom

Once again, I am learning a great deal from one of your posts, Tom. I think I will adopt your methods for handling Eneloops.

Many thanks.

 

[gdillainepub]

maha user manual quotes an IEC norm. i looked it up. the norm states that the battery needs to be discharged first.

i don't do break-in anymore, ive become lazy with keeping up things. but when i run break-in program in maha or 2500, i discharge first.

Yeah, as said, Eneloops don't require a break in. I have done tests, and the difference you get from doing a break-in, vs. just charging and using, is about 1%-2% extra capacity from a break-in. However, that benefit is only in the first 1 or 2 cycles. After you've used the Eneloops a couple of times, there will be no difference in capacity whether or not you did a first initial "break in".

So, don't bother.

Thanks guys, now at least i know I do the break-in correctly, i,e, discharge and break-in

I understand the Eneloops are good to go out of the box.

However, as many documents has explained as well as the MAHA C9000 manual:

(i) the point for Break-in has nothing to do with LSD, but the NiHM chemistry per se
(ii) and the Break-in has nothing to do with "memory effect" - if you wanna get rid of the memory, run a few cycles of charge discharge seems to be the way.

According to what I have read, the point of Break-in is:

(i) Used when: a NiHM cell has been stored for a prolonged time; or the cell has been used for many cycle where a drop in capacity is obvious and a "Refresh" cannot restore those lost capacity.

(ii) the theory is that the cell is dormant for a while (kept for a few months without use) , or it has been used for many cycles, crystal formation occurs in the cell which increases the internal resistance, and those crystal formation depletes some of the cell's capacity. The break-in procedure is believed to be able to break down those crystals, restoring the chemicals in the cell back to the forms they are should be. The crystal formation, and the crystal lattice that comes with it, are the reason of increased electric resistance (the electrons needs more "force", i.e., voltage, to flow through the lattice). And since portion of the chemicals which were able to hold or facilitate the charge have become crystal, which loses its original properties to hold/facilitate charge, the overall capacity of the cell decreased. So break down these crystal formation and restore the chemicals to a form charges can be held/facilitated, some capacity of the cell can be regained.

I believe this is the underlying rationale why break-in applies to all NiHM cells -- LSD or not. But i would also agree that for Eneloops, their refined chemistry/design compared to conventional NiHM cells may diminish the need for break-in to a notable extent.

 

[gdillainepub]

maha user manual quotes an IEC norm. i looked it up. the norm states that the battery needs to be discharged first.

i don't do break-in anymore, ive become lazy with keeping up things. but when i run break-in program in maha or 2500, i discharge first.

I approach this from a little different perspective...

Usually I don't need the cells immediately, but if I did I would use Eneloop cells right out of the package.

I anticipate using these cells in multi cell applications. I have found that by matching the cells in these applications I get better performance.

Normally I will discharge the cells first, followed by a Break In. I make note of the capacity. This becomes my "benchmark" for when to retire the cell. I retire when the cell drops below 80% of this initial capacity.

The next step is to match the cells based upon normal charging and discharging conditions. With Eneloop cells I charge at 1000 mA and discharge at 500 mA and find that covers many of my applications.

Now I am ready to use the cells and know what I am working with.

Tom

Another matter regarding Discharge, I would like to have your people's opinion.

@kreisl and @Silverfox (Tom)

What is your opinion regarding to the terminal voltage for discharging.

Both MAHA C9000 (not explicitly specified in the manual but i observed so) and SKYRC 2500 defaults end of discharge to 0.9V. However, the IEC 61951-2 (ver. 2011) standard, which is the same IEC standard the "break-in" procedure derived from, says the cell should be discharged to a final voltage of 1.0V.

What do you think? On chargers that can control the final discharge voltage, like the SKYRC NC2500 and the upcoming MC3000, will you go with the default 0.9V setting, or the 1.0V as defined by IEC61951-2.

(I cannot attached IEC document via quick reply -- i'm going to try to see if the "advanced mode" can attach the document)

 

[kreisl]

What is your opinion regarding to the terminal voltage for discharging.

Both MAHA C9000 (not explicitly specified in the manual but i observed so) and SKYRC 2500 defaults end of discharge to 0.9V. However, the IEC 61951-2 (ver. 2011) standard, which is the same IEC standard the "break-in" procedure derived from, says the cell should be discharged to a final voltage of 1.0V.

C9000 defaults end of discharge to 1.0V for Break_in, you can check with multimeter. Also see HKJ's measurements. (but you're right that for all other modes, the charger defaults to 0.9V.)
C3000 also defaults to 1.0V and afaik this value, the parameter for option CUT VOLT in the Break_in operation mode, cannot be changed.
C2500 defaults to .. erh .. i didn't test. HKJ's measured it too.

1.0V is the correct value. C9000 and C3000 use this in practice, don't worry.

 

[gdillainepub]

OK. It seems the "advanced mode" cannot attach neither the pdf or a screenshot JPG. Guess I could only paste the original paragraph here:

Prior to charging, the cell shall be discharged in an ambient of 20 °C ± 5 °C, at a constant current of 0,2 It​ A, down to a final voltage of 1,0 V.