Maha MH-C9000 SUPPORT / FAQ - continuation

[lee5079]

Mr. Happy, 45/70,

Thanks for the reply + welcome, wanted to reply this last night at home ( my time is GMT +8 ) but my ISP is pretty bad that i couldn't even sign in.

I have read the previous long ver 1 thread but not this one.. hopes to go through them when have the chance and the information here was one of the deciding factor for me to get the charger. I was initially wanted to design my own "ultimate brilliant charger" ( I still do now ) but thought the C9000 will do the job for me.

45/70, those batteries returned an immediate DONE on discharge even at 100mAH is chosen. So, pretty no hope but I managed to cheat the charger to bypass the checking ( I am a Firmware Engineer myself and I managed to figure out how most designer will forgot how to handle certain cases after few key pressed last night ). Hopefully the charger is smart enough to avoid overcharging those high resistance cell while I am forcing them to cycle on low current charge / discharge. Anyway, this experiment will be carried on later as I terminated the cycle after I knew I can cheat the charger... This is to give way to other batteries to be tested.

I have collected a series of googled information hoping that one day i can get my lazy butt up to design some special charge / discharge stuffs that work better. Examples are reading someone's post that we can do some slow discharge + Rest + short charge + Rest + slow discharge + Rest + short charge repetitive cycles which will "hopefully" breakdown some large crystallite and reducing the internal resistance.

So far, I have my fellow photographer friends to donate their unwanted NiMH to me so that I have a pool of samples to play with. .. what am I getting myself into this time ... and let see how long this will go before I am getting bored and put it aside and just use the charger

 

[InHisName]

So, pretty no hope but I managed to cheat the charger to bypass the checking ( I am a Firmware Engineer myself and I managed to figure out how most designer will forgot how to handle certain cases after few key pressed last night ). ...

I cannot recall hearing that there is a way found yet, please tell the details to how to 'cheat' the HIGH etc.

I am not too sure of the usefulness as the 100Ma charge is really 2Amp - 5% of the time charge. A better charger for these junk cells would be a 100ma continuous charge 100% of the time. Finding a charger that does INDIVIDUAL cells @ 100Ma isn't easy.

 

[lee5079]

I cannot recall hearing that there is a way found yet, please tell the details to how to 'cheat' the HIGH etc.

I am not too sure of the usefulness as the 100Ma charge is really 2Amp - 5% of the time charge. A better charger for these junk cells would be a 100ma continuous charge 100% of the time. Finding a charger that does INDIVIDUAL cells @ 100Ma isn't easy.

Hmm.. I wonder if this "feature" will be removed after MAHA see this .
What I did was to put in a good battery and select the intended program, let the initial checking do all the works.
- Next, select a slot that are having at least completed 2 cycles or more. (this seems like a Prerequisite actually)
- Press the UP or DOWN arrow key and hold. You will see it is busy switching between the CYCLEs
- While doing the button HOLD, swap in the battery which the Charger rejected earlier.
- Release the hold button. I managed to get this to cheat the charger that it doesn't detect the battery is changed.

Not sure if a fast replace is needed but so far it works for me. The steps could be simpler but I didn't manage to get this to work until I try it with a Up and Down on a slot which have different cycle displayed.

I have suspected the battery detection used in this Charger is based on polling and not an interrupt based design and hence making the Charger Busy while swapping the battery would be a loop hole.

 

[InHisName]

I tried on mine but it kept cycling no matter what I tried. Holding down on down arrow button, up arrow button, enter all after one cycle of display would move to the next slot and start displaying that one. Pressing and holding the slot button makes it cycle quickly between batt slots.

No matter how quickly or which button holding, I get the prompt to setup new battery settings. This happens each time I insert the 'bad' battery to fool the C9000.

I have revision: 0G0B01 on back above 'made in japan'

 

[Mr Happy]

A way of tricking the charger that other people have used is to insert the bad battery in the slot and then "piggy back" this battery with a good battery using small pieces of foil or thin wire held in place with the fingers. Then program the slot to the desired charge program. The good battery will cause the initial resistance check to succeed and then this battery can be removed allowing the charge program to continue with the bad battery.

Be aware however, that if you attempt to charge a high resistance battery at a normal charge current it may get very hot.

 

[Battery Guy]

Re: Maha MH-C9000 SUPPORT Thread

What is the maximum capacity supported by the MH-C9000?

The maximum capacity supported is 20,000mAh making it compatible with future technologies.

When one considers that this charger is limited to charging AAA and AA NiCd and NiMH cells, I find this statement extremely amusing. A 20mAh AA NiMH cell!

I think that this guarantees that the MH-C9000 will be compatible with the NiMH technology until our universe experiences heat death.

Kudos to Maha for making this a selling point for their product!

Cheers,
BG

 

[45/70]

Unfortunately, waaay back with the first major revision of the C9000, about when they added the 50 Watt HID backlight for the LCD, they revised this figure to 4000mAh. If you'd read the entire thread BG, you'd already know this! After all, it's only 547 posts!

Dave

 

[Battery Guy]

Unfortunately, waaay back with the first major revision of the C9000, about when they added the 50 Watt HID backlight for the LCD, they revised this figure to 4000mAh. If you'd read the entire thread BG, you'd already know this! After all, it's only 547 posts!

Dave

My bad. I knew it was a risk to post to a thread with so many posts, but I really did attempt to make it a semi-legit post.

Seriously, this looked like a really good thread and I started reading through it. I even searched this thread for the word "future" to make sure that nobody else had commented on the whole 20,000 Ah issue. But I totally missed the change from 20 to 4 Ah capacity limit. There is a chance (albeit limited) that my son might see a 4 Ah AA NiMH cell in his lifetime. Probably about the same chance that he will see a 4 Ah 18650 lithium-ion cell, but I digest.....

Now I need to go back and read more about this 50 Watt HID backlit display.

Sorry for not contributing anything useful to this thread.

Cheers!
BG

 

[tandem]

My 0J0DA rev C9000 comes with the "HID" backlight (I love that glow in my otherwise dark office) and a manual that still claims 20,000mAh supported capacity.

I'm happy to forgo reading the *entire* thread, ignore the errata, and live in a delusional world of NiMH AA cells with titanic capacities. Can't wait for the 8,000mAh AAAs!

 

[Bones]

My 0J0DA rev C9000 comes with the "HID" backlight (I love that glow in my otherwise dark office) and a manual that still claims 20,000mAh supported capacity.

I'm happy to forgo reading the *entire* thread, ignore the errata, and live in a delusional world of NiMH AA cells with titanic capacities. Can't wait for the 8,000mAh AAAs!

Why wait when you can use the break-in mode now to analyze, slow charge and check the capacity of your C & D-cells.

And if you (ahem) happen to have a first release of the MH-C9000, you can use this set-up to actually bring its full slate of modes to bear on C & D-cells, including charging up to 20000mAh cells at its maximum rate:

Well here's my latest invention, based on ideas I've gleaned from others on this forum.

18 gauge copper wire with #8 ring terminals soldered on the ends.
Hardwood dowels with electrical tape on the ends (in case there is any moisture in the wood).

1/4" nickel plated rare earth magnets hold the ring terminals to the positive and negative ends of the batteries.

The D cell holders that are available locally are $5 a piece and have 22 or 24 gauge wire attached.

The holders I really want are too expensive to obtain at the moment, so this will suffice for now.

 

[lee5079]

I tried on mine but it kept cycling no matter what I tried. Holding down on down arrow button, up arrow button, enter all after one cycle of display would move to the next slot and start displaying that one. Pressing and holding the slot button makes it cycle quickly between batt slots.

No matter how quickly or which button holding, I get the prompt to setup new battery settings. This happens each time I insert the 'bad' battery to fool the C9000.

I have revision: 0G0B01 on back above 'made in japan'

I gave it another tried with 2 of my HIGH battery using the method and it seems still working for me. Even just press and hold the SLOT button works for me. I forgot to note down my unit's revision.

What Mr. Happy stated was one of the thing I have in mind to try before I getting the stuffs to work using keypressed. Parallel the cells so that the high resistance test will have past in the first place before removing the good one.

 

[Bones]

A way of tricking the charger that other people have used is to insert the bad battery in the slot and then "piggy back" this battery with a good battery using small pieces of foil or thin wire held in place with the fingers. Then program the slot to the desired charge program. The good battery will cause the initial resistance check to succeed and then this battery can be removed allowing the charge program to continue with the bad battery.

Be aware however, that if you attempt to charge a high resistance battery at a normal charge current it may get very hot.

Thanks Mr Happy, I hadn't heard of this technique before now. It may provide a viable way to bring the MH-C9000's versatility to bear to recover cells that have slipped over the 'HIGH' threshold due to a lack of conditioning.

 

[Bones]

...

I have revision: 0G0B01 on back above 'made in japan'

Interesting, has MahaEnergy changed the manufacturing locale of the MH-C9000, or does it actually read Taiwan?

 

[Turbo DV8]

And if you (ahem) happen to have a first release of the MH-C9000, you can use this set-up to actually bring its full slate of modes to bear on C & D-cells, including charging up to 20000mAh cells at its maximum rate:

I've twelve Powerex D-cells that I would love to finally be able to do this to, but apparently I have the 4Ah limit on my C9000. If I wanted to pick around the BST forum, what serial number/rev, etc. should I be looking into over there if I want tos score an earlier 20Ah C9000? Other than that current limit and the backlight, and IIRC, a 1.0 V discharge cutoff as opposed to 0.9 V, any other differences?

Any thoughts on the little issue I posted in post #540?

 

[Bones]

I've twelve Powerex D-cells that I would love to finally be able to do this to, but apparently I have the 4Ah limit on my C9000.
...

Don't forget that yours still has the 20000mAh setting in the break-in mode, so if you utilize a timer and set the capacity to 11000mAh, you can effectively bring a standard or 0.1C charge to bear for up to sixteen hours. You can also, of course, utilize the full break-in cycle and the straight discharge mode.

...
If I wanted to pick around the BST forum, what serial number/rev, etc. should I be looking into over there if I want tos score an earlier 20Ah C9000?
...

You definitely want it to state 0FAB01 on the label. However, since MahaEnergy introduced the first revision on the fly, so to speak, some chargers bearing 0FAB01 on the label actually received the revision. Keeping this in mind, the easiest way to identify a first edition is to make sure it has the appropriate label and charges a quality cell like the Eneloop well past 1.47 volts.

Here's an actual image of the label on my first edition MH-C9000:

http://www.candlepowerforums.com ... post3072027

...
Other than that current limit and the backlight, and IIRC, a 1.0 V discharge cutoff as opposed to 0.9 V, any other differences?
...

Yes, the big one is that rather than a peak voltage algorithm and a two hour top-off charge, the original edition utilizes a true -dV termination protocol. This directly effects both the minimum rate of charge you can safely employ and the temperature of the cells during the latter stages of the charge at higher rates.

As well, it removes the load during voltage readings while discharging, which substantially delays the process. On marginal cells, the voltage keeps rebounding when the load is removed, so it keeps trying to discharge them further even though there is no real capacity remaining.

...
Any thoughts on the little issue I posted in post #540?

Sorry, no, other than ghosts in the machine or just your damnable luck with electronics...

 

[Bones]

Welcome to CPF lee5079! :thumbsup:

It has been a while since I had any cells demonstrate that behavior. Mr Happy is right, it is an indication that the cells are in really bad shape.

I realize you said you could not get any program to work, but did you try "DISCHARGE"? If you insert one of these cells and set the C9000 to discharge @100mA and it works, there may be some hope. I remember having some very old NiCd cells that behaved like that. I can't remember if they could be discharged on the C9000 though. If you can get a 100mA discharge to work, partial recovery may be possible. As Mr H alluded to however, the process is a lot of trouble and the chances for success are slim.

Dave

This harkens me back to the termination problems we encountered with the original release of the MH-C9000. It seems that MahaEnergy just plain lacks an array of cells that are truly crap to test their designs with.

Perhaps we should send William Chueh a broad selection. He can then design in the appropriate response so we don't encounter this rather odd behavior when the worst of the worst cells are inserted.

 

[45/70]

Sorry for not contributing anything useful to this thread.

Um, BG, you did realize I was just messin' wid ya, right? :thinking:

and a manual that still claims 20,000mAh supported capacity.

As far as the "manaul", as it is referred to on the back of the C9000, I think both the .pdf and the printed version, have remained unchanged since the very first chargers were released. This also was discussed some number of pages back in this thread. I haven't checked either version in a while, maybe they are updated now.

Any thoughts on the little issue I posted in post #540?

Turbo, I think mine show a quirk every once in a while. I have been just attributing it to the variable mains power out here in the country. I doubt if it is of any concern. If something consistent keeps showing up, I'd just give Maha a call and see what they say.

It seems that MahaEnergy just plain lacks an array of cells that are truly crap to test their designs with.

Gee, I wonder why that is? Everybody should keep at least a few crap cells that aren't good for much anything, right?

Perhaps we should send William Chueh a broad selection. He can then design in the appropriate response so we don't encounter this rather odd behavior when the worst of the worst cells are inserted.

I'm sure that would really make his day.

Dave

 

[Turbo DV8]

Gee, I wonder why that is? Everybody should keep at least a few crap cells that aren't good for much anything, right?

Thing is, what is one man's crap, is another man's candlepower. I have (and use) many "crap" cells to power my hallway LED candles, all night, every night for three weeks on a charge. I just can't charge them on the C9000. Admittedly, that type of low-drain application is about all they're good for!

 

[mellowman]

My 0J0DA rev C9000 comes with the "HID" backlight (I love that glow in my otherwise dark office) and a manual that still claims 20,000mAh supported capacity.

I'm happy to forgo reading the *entire* thread, ignore the errata, and live in a delusional world of NiMH AA cells with titanic capacities. Can't wait for the 8,000mAh AAAs!

I recently bought one and have the same rev, OJODA. The manual states 20,000mAh supported and max charge rate of 2,000mA. The break-in menu can be set to 20Ah and the charge menu can be set to 2A.

Not sure where the 4Ah limitation is supposed to show up. Maybe it doesn't exist anymore, or maybe never did.

 

[digitor]

I recently bought one and have the same rev, OJODA. The manual states 20,000mAh supported and max charge rate of 2,000mA. The break-in menu can be set to 20Ah and the charge menu can be set to 2A.

Not sure where the 4Ah limitation is supposed to show up. Maybe it doesn't exist anymore, or maybe never did.

.