Different chargers can use different ways of discharging even with the same current indicated. Some can use a pulsed mode where the “average” is the indicated current. The method of discharge might cause the differences that we are seeing.
Pulsing for NiMH-charging is normal, but not sure how it works with discharging.
I took a look at discharging graphs at HKJ and the Powerex MH-C9000 seems to be a bit strange
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The Lii-500S graphs looks more like what I expect
Not sure how Powerex discharge function works, NiMH cannot deliver extreme currents, if I choose a low discharging rate, the C9000 pulses very high but in big intervals it´s not good for the cell I would assume
If it is bad for the cells… well my 10+ year old Eneloops don’t seem to have suffered much. But sure, I don’t have a control group to compare.
I mean for discharge, don´t know how often you discharge your cells with the C9000
I tend to run the refresh cycle maybe once per year. When a cell is getting a bit tired, I run the break-In cycle. SO I would guess that all of the cells have been discharged at least ten times in the MC9000.
I was just saying that from my experience the pulsed charge/discharge does not seem to hurt the cells. At least not significantly. But who knows, maybe using a non-pulsed discharge is better. But probably not enough so that a typical user would ever notice it. One of those things that we perfectionists can agonize over though… 
Yeah, who knows 
In most common usage you won´t have a very high pulsing current, high currents stress the cells. A linear lower current looks more realistic to me. So I don´t understand Powerex decision to pulse high currents to get an average current.
In Break-In-mode the currents are 0.1C, should not hurt that much.
Soon I will get the C9000 Pro and will compare both chargers
I just re-read this. The pulses are the same magnitude all of the time, just spaced differently to get the average that you select.
So in some cases they might be considered high for the smaller cell capacities. But I don’t believe that it is enough to damage cells, or even significantly reduce cycle life. This based on personal experience plus the fact that they have been doing this for over a decade. I have yet to find anyone that mentioned negative effects over time. I am pretty sure someone would have documented the problem if it exists.
I will be interested to read what you think of the “PRO” model.
Maybe it not damage cells but I think the kind of the stress is not realistic. Photoflash needs for a short time high current, OK, but not in this frequency. Other kinds of stress need lower current but permanent, not pulses
I think I see your point. But if it does not damage the cells, if it fully charges the cells, and if capacity readings are accurate, I just don’t see the concern. BTW capacity reading do agree within a few percent with 4 other chargers that I have compared it to. Including my MC3000 and the well loved Vapcell S4+ V2, BT-C3100 V2.2, and the Xtar VP4 Dragon Plus .
So while I can understand your concern, if the results are uniformly good, I don’t see the charging/discharging method that Maha uses as being a problem. I think that, after 12 plus years of making chargers using it, if people were having any problems, it would have been documented well by now.
Tried my new Powerex MH-C9000 Pro a bit.
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Instead of 11 cells I get only the message „high“ at 2 cells.
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I can easily discharge the cells with 1A and have a fitting result, even it´s lower than with some of my other chargers. But not to compare with the C9000 with shows values of ca. 300mAh while the Pro shows around 2000mAh. The huge voltage drop from the C9000 at discharging happens not with the Pro, at beginning of 1A discharge it´s 1,3V while the C9000 drops after some seconds to <1,1V.
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The memory of the last used mode and current is fine.
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It seems to be faster at cahrging with the same currents
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The bad/critical cells getting hotter than with the C9000, the display is awful to read if you don´t look in the right angle.
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The buttons don´t react so good, sometimes a 2nd press is needed
That´s my first impression, overall I would say at the moment it´s an improvement over the C9000, at least in the cases I tried
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Addition: After testing more problematic cells I would say the C9000 is more worse than the C9000 Pro. Stopped some cells which were loaded with over 3300mAh, I would expect max. 2300mAh. Temperatures almost 60° Celsius
So my actual conclusion is:
- the C9000 is more overhyped than I thought
- I have a defect/buggy device
- other users of the C9000 use only very unproblematic/good cells
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Fwiw i got 2 of the first batch of c9000.
These had firmware bugs and were replaced in the first 4 months.
The display failed in one of the replacements.
Replaced under warranty.
Seems many maha/powerex products have teething pains and are reasonably good after that.
And on aaa cells if the wrappers curl over the bottom of the cell you get contact issues.
Bought it used, don´t know from which batch it is and which FW it have. Can´t remember to see it anywhere.
My Skyrcs and Opus show a FW at powered on, but Maha?
According to one post the firmware level for the C9000…
“It will be printed on the bottom of the unit near the bottom of the sticker.”
I have three. I just checked and the most recent one (Maybe 12 years old) shows 0K01A.
Then 0K0AA for one a round 14 years old
Then 0G0C01 for the (around) 11-12 year old ones.
As of the middle of 2007 the shipping firmware was 0G0D01
I don’t remember if the firmware is user upgradable… I have never done any of mine.
BTW, those ages are very approximate for mine. It has been a long time and I really can’t recall exactly when I got them. The all work just fine as of a few days ago.
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I have some kind of rebadged charger
I think the bottom number is the serieal number but I don´t see a FW-version
Well that is different. I don’t know how to find the firmware revision on that one. So far, I can’t find any information on user update of the firmware.
I did find this:
“It is only the first two digits that designate the firmware version.
All of the units that begin with “OG” all have the same firmware.”
Not that it helps you. The A04 on yours does not seem to correlate with the Maha designation… nor the Lacrosse “clone”/rebrand version ( I think that one may be at V33). Maybe you could contact the ELV ElektroniK AG folks and ask ??
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ELV is an electronic online shop in Germany, don´t really think they have answers about the FW-version.
Maybe the FW would clarify things but not solve the problems.
I get it, but you won’t know until you ask.
True about the firmware, but maybe worth a try.
The thing probably won’t fix itself… 
Yeah, that´s the problem
But I use it not that often, for NiMH I mostly use the Vapcell S4+, Opus BT-C3100 and Nitecore UMS4