With MHC-9000, preferred to do DISCHARGE prior to BREAK-IN with rechargable AA's?

I've got a set of four new 2400 mah Duracell ION-CORE (apparently Eneloop clones) and a Maha MHC-9000. I was getting ready to do the 39 hour BREAK-IN, but I got to wondering if it would be ok, flawed, or doesn't-matter to do a pre-DISCHARGE cycle prior to the BREAK-IN.

My impression is that the MHC-9000 does an 18 hour slooooow charge, then rest, then discharge, then another sloooooow charge, than another rest as the BREAK-IN cycle. The batteries are already partially to mostly charged from the "blister pack".

My less-than-informed thought was perhaps it would be advantageous to pre-DISCHARGE the batteries before the BREAK-IN. Or not? Are the 5-steps above appropriate and optimal? Or near-optimal?

If it helps to DISCHARGE prior to BREAK-IN, then what would be a preferred rate of DISCHARGE? The default 500 mah? Higher? Lower?

Partial drain? Full drain?

Or does it not really matter? Am I shooting myself in the foot? Out-smarting myself out of ignorance? Over-kill?

I don't have immediate need for the batteries, so taking time to get best long-term results is an option. My speculation is that Maha may have designed their BREAK-IN cycle to be a trade-off between optimal BREAK-IN, but not taking too much time. Their BREAK-IN already takes more time than I would have expected.

I've come across threads that mention pre-discharge, but I was unclear if this was "best practice" or not. Also, what are the specifics of a "best practice pre-discharge"?

In my opinion as i don't really know if it would make it worse, i think you could badly overcharge a LSD NiMH cell by doing the break-in first. Of course that could be remedied by discharging the cell afterwards, but i see Eneloops and the Duraloops do not require a break-in and a simple test or charge, discharge, charge is good enough to get a reading of how well the battery functions. Most other off brand batteries i have noticed needed a jump start and they would benefit more from a break-in upon purchase or when found that refreshing does not help the batteries out much.

Some people swear up and down that doing a break-in on Eneloops is best for them, but the only time i would think they would need one is if they have been sitting on the shelf for several years. If the date code on them looks good give them a refresh/analyze and see how they do. I'd do the lowest discharge current and 500mA should be ok which i consider to be a 'mini break-in', after that use the default charging on the cells. I don't think there's any need to spend 40+ hours in trying to get fresh cells going when they work well right out of the package. Again this is just my opinion, others might think a break-in is necessary. While the C9000 had LSD cells in mind when they manufactured it, i have some LSD cells that required a bit of refreshing and they could have really benefited from the C9000's break-in but test out the Eneloops, if they discharge fine and have good capacity they are good to go.

If you do plan on doing the break-in on your Duraloops, discharge them first. As for the discharge rate, i'd probably choose 500mA or higher if i was in a rush. 300-500mA for discharging i think would be fine.

Re: With MH-C9000, preferred to do DISCHARGE prior to BREAK-IN with rechargable AA's?

MidnightDistortions said:

LSD

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Sorry, this newbie is being slow, but I'm unclear on what "LSD" stands for ... "long slow discharge"? Or is it a brand name? I've seen the initials all over the place, but not what it stands for.

Eneloops and the Duraloops

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Also being slow here. What is a "Duraloop"? Is it the same ... or similar ... to Duracell? Is it a "nickname" for a Duracell that is really a clone/rebranded Eneloop?

Re: With MH-C9000, preferred to do DISCHARGE prior to BREAK-IN with rechargable AA's?

L_D_Allan said:

Sorry, this newbie is being slow, but I'm unclear on what "LSD" stands for ... "long slow discharge"? Or is it a brand name? I've seen the initials all over the place, but not what it stands for.

Click to expand...

LSD stands for low self discharge. HSD is high self discharge

Also being slow here. What is a "Duraloop"? Is it the same ... or similar ... to Duracell? Is it a "nickname" for a Duracell that is really a clone/rebranded Eneloop?

Click to expand...

Duraloop is just a nickname for the Duracells that are rebrand Eneloops.

Re: With MH-C9000, preferred to do DISCHARGE prior to BREAK-IN with rechargable AA's?

Hello L D Allan,

In theory it shouldn't make any difference because the charge rate is supposed to be low enough to avoid damage. We are still learning about low self discharge cells so in actual practice we recommend doing a discharge (at 500 mA) prior to starting the Break In.

Tom

Re: With MH-C9000, preferred to do DISCHARGE prior to BREAK-IN with rechargable AA's?

SilverFox said:

In theory it shouldn't make any difference because the charge rate is supposed to be low enough to avoid damage. We are still learning about low self discharge cells so in actual practice we recommend doing a discharge (at 500 mA) prior to starting the Break In.

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Thanks! ... to both replies.

I'll proceed with more confidence that I am not yet again shooting myself in the foot.

Is the following more or less what might be going on to possibly make the C9000 BREAK-IN less than optimal:

• The AA battery starts near full-charge at about 1.30 to 1.35 volts
• It gets a 0.1c trickle charge for 18 hours, which would be over-charging towards 1.50 volts for 12 to 15+ hours, even though at a 0.1c trickle rate
• Then Rest, then Discharge back to ~ 1.0 volt
• Then "safe" 0.1c trickle charge for 18 hours, so much less of the trickle over-charging is taking place beyond "true full charge" of about 1.45 v
• Then Rest.
• Or not?

And overall, the reality is that it may very well not really make much if any difference. The Duraloops might retain full performance for 800 cycles rather than 700 cycles ... 15+ years instead of 13+ years.

Re: With MH-C9000, preferred to do DISCHARGE prior to BREAK-IN with rechargable AA's?

Hello L D Allan,

The Break In procedure revolves around normal NiMh and NiCd cells. Those cells don't care if you do the Break In on charged or discharged cells. The charge rate is low enough that it doesn't cause problems.

The electrolyte in these cells is basically starved. The low charge over a long period of time is supposed to redistribute the electrolyte evenly throughout the cell. The result is often that a cells "vibrancy" is restored. Low self discharge cells are basically the same but they seem to be more sensitive to overcharging so that is why we recommend a discharge prior to the Break In.

Technically the Break In is charging for 16 hours (not 18) and this is not a trickle charge. A trickle charge is the charge given after the main charge is complete. The 16 hour charge is the main charge and it is terminated by time.

In general, "vibrant" cells perform better and last longer than "marginal" cells do. The goal is to keep your cell "vibrant." If the cell is in constant use a Break In cycle may not be needed often. Cells in storage benefit from a Break In about once a year.

Tom

Re: With MH-C9000, preferred to do DISCHARGE prior to BREAK-IN with rechargable AA's?

Thanks for patiently and gently "correcting the error of my ways" / misconceptions. I've learned quite a bit on the forum. Terrific resource.

Update: I did the DISCHARGE at 0.13c (about 300 ma/hr?), and the C9000 indicated DONE when the set of four DuraLoop 2400's were uniformly at about 1.18 volt. That was a bit higher than I expected, but probably safer/healthier than being dragged down even further to abusive levels.

They are now getting the BREAK-IN cycle with 2400 mah specified. Thanks.