Maha MH-C9000 SUPPORT / FAQ - continuation

[Mr Happy]

Well I have the ogoka version and i just finished a break in of my ''duraloop cells. They were 1968,1921,1955,and 1978. I did a 400ma discharge after that and I still got 1974,1926,1959, and 1986 respectively. Isn't that on the low side?

It lines up exactly with the numbers I measure on my cells.

Note that your second discharge gave slightly higher readings. If you have the patience you could do another one or two break-in cycles to see if they increase any more.

 

[chewy78]

I could break them in again, then my other cells will get jealous of them. but first I have to break in the other duralooops and energizer 2100's I have, so I have a base line to go on. This charger is kinda neat.

 

[Doug.S]

This is a new item but under this generic title topic....

I bought a C9000 about a year ago. Last Dec. slot 1 died....it got stuck trying to ALWAYS charge (as shown in the display) even with no batts in it....and would not reset after being unplugged for days....tho the start-up display seemed normal.

So nicely and responsibly it was replaced by mfr under warranty as being defective. That was just fine.

But now the replacement unit is doing the same thing...so I wrote but not heard back as yet.

My question is: others experiencing this same problem? is it a frequent problem? is there anyway to prevent such occurrence?

I am a low usage user... 2 to 4 AA batts charged per week and do not do anything unusual with batts or charger.

Doug.S

 

[TorchBoy]

Hi Doug. It sounds like a problem I had, where the charger would think there was a cell in slot 2, then restart instead of charging it, and hence just endlessly restarted/rebooted. There have been a few others with the same problem.

What batch number does your present one have? It's on the label on the back, something like 0G0B01.

 

[TorchBoy]

Before I forget it, the manual that came with my latest MH-C9000 (0H0AA) still has the minimum recommended charge rate of 0.3C.

 

[SilverFox]

Hello Ian,

Yes, I don't believe the manual was included in the improvement...

Tom

 

[TorchBoy]

Tom, in the Cycle mode when it pauses for two (!) hours after charging, is it doing a top up charge? You don't mention it in your comparison.

 

[Mr Happy]

in the Cycle mode when it pauses for two (!) hours after charging, is it doing a top up charge?

I don't know the answer to this, but there is a way to determine what it is doing.

You can use an Eneloop for testing and watch it after the charge completes. The normal charge will finish when the cell reaches 1.47 V, and the voltage will then drop back down a bit, say to 1.45 V. Now if a top off charge is being applied the voltage will slowly creep back up again to 1.48 V or 1.49 V over the next two hours. However, if no top off charge is being applied, the voltage will stabilize at 1.45 V or even drop down to about 1.43 V.

 

[TorchBoy]

Yes, I think it did increase, which is why I first thought it was charging. Then I noticed that it took 2 hours, not the 1 hour the Break In rest takes. I'll run another test to confirm.

 

[SilverFox]

Hello Ian,

I believe we looked at that, but I can't find the information.

For some reason I think it does a trickle charge during the two hours between charging and discharging, bit I don't know that for sure.

Tom

 

[Doug.S]

Hi Doug. It sounds like a problem I had, where the charger would think there was a cell in slot 2, then restart instead of charging it, and hence just endlessly restarted/rebooted. There have been a few others with the same problem.

What batch number does your present one have? It's on the label on the back, something like 0G0B01.

0G0IA

 

[Doug.S]

Hi Doug. It sounds like a problem I had, where the charger would think there was a cell in slot 2, then restart instead of charging it, and hence just endlessly restarted/rebooted. There have been a few others with the same problem.

What batch number does your present one have? It's on the label on the back, something like 0G0B01.

0G0IA

Maha is sending another replacement and will test this failed unit I'll return to them.

 

[junglemike]

Hi. I am new Maha c9000 user. I have couple of questions, hope you can help me.

Question #1)
Suppose I perform a Refresh&Analyze function on some specific battery, choose charge current 700ma, discharge 400ma. When operation is done, capacity is (in my particular case 1320)
Than I do a charge mode of the same cell @ 700ma, than let it rest 20-30 min (not 2 hours as it rests in refresh mode) And then i perform a discharge operation @ 400ma, Result capacity is 1190 - somewhat less.
And the same pattern repeats itself with many cells, not just one.
Can anybody explain this?

Question #2). I have some very old dead cells, that i'm trying to revive.
They apparently have high internal resistance. Once i charge them (with slow current) and try to perform a discharge operation @ 800ma - I get DONE after less than 1 min, and capacity is 0mah (maybe 1-2mah)
Now, when i set a discharge current to be 100-200ma, it discharges it for a long time and reaches >1000mah. But more interestingly, voltage stays very low all the time <1v (0.94, 0.95v etc...)
I've read that it terminates the discharge process when cell reaches 1v. So how is tis possible? And what to do with these old cells to try to revive them?

 

[SilverFox]

Hello Junglemike,

When you perform a discharge 20 minutes after Done is displayed, you are cutting out the top off charge. The C9000 applies a 100 mA top off charge for 2 hours after Done is displayed. If you add a little less than 200 mAh, due to charging inefficiencies, to your results, you should be close to what you saw on the Refresh/Analyze mode.

Crap cells should be recycled. If you want to play, you can do 12 cycles of Refresh/Analyze using 500 mA charging at 100 mA discharging. At the end of this, do a 1000 mA charge, wait 2 hours to complete the top off, then do a 500 mA discharge. This will give you an idea of how well your efforts paid off.

Now that you have run your experiment, recycle the cells if they have not returned to at least 80% of their labeled capacity.

Tom

 

[Glock40]

I have a quick question that I felt did not warrant starting a new thread. Just bought a pack of 4 Duracells 2650mAh. I am wanting to do a break in on these using the C-9000. When i am prompted to enter the capacity i have to choose either 2600 or 2700. Should i go hi and select 2700 or stay safe and select 2600.

 

[Black Rose]

Go with 2600.

I asked a similar question with regards to some 750 mAh AAA cells I had.

The C9000 will put more charge into the cells during break in.

Here is the response I received regarding my AAA cells:
https://www.candlepowerforums.com/posts/2403650&postcount=14

 

[junglemike]

SilverFox, thanks very much for your valuable advice.

 

[TorchBoy]

I've read that it terminates the discharge process when cell reaches 1v.

It was only the very first release of the C9000 that terminated at 1 V. All the more recent ones terminate at 0.9 V.

 

[stroberaver]

Ok, so I'm in the market for a C9000, but naturally would prefer one of the later revisions without the cycle bug. I spoke to the UK distributor who said they received their stock at Christmas / end of last year. Is this likely to be recent enough to ensure getting a later revision? Anyone have an idea of when the revised versions entered the shipping/wholesale channels?

Thanks in advance.

 

[TorchBoy]

Very likely stroberaver. If you want to be really sure, get them to have a look at what batch number is on one before you buy it. It seems to take at least 2 or 3 months for new batches to get on the market but that will vary all over the place depending on stock levels of older ones.