Does the C9000 top-off in R&A mode?

[bcwang]

I think while searching through the threads, I encountered statements that the C9000 does not top off in Refresh and Analyze mode, and also read statements that it does. In fact I believe I read two separate posts by Will Cheuh (maha rep) where one said it doesn't, and the other said it does.

So I just want to set the record straight here, does it or does it not top off in every mode except "break-in" and "discharge"? Or does it depend on which generation of firmware is in the unit?

By the way, I guess there are two possible top off points in the R&A mode. One is after the initial charge where there is a 2 hour wait before discharge, and one is after the testing is done and the battery is fully charged again. So specifics would be good.

Top off current is 100ma for 2 hours no matter AA or AAA right?

Thanks!

 

[bcwang]

Ok, from reading more and more threads trying to get a handle on this situation, this is my conclusion. Anyone with better knowledge please correct me.

On the original C9000 Refresh and analyze - Charge until termination, stop for 1 hour with no current, then discharge to 1v resting voltage, then rest one hour, then charge until termination, then trickle at 10ma indefinitely.

On the "improved" C9000 Refresh and analyze - Charge until termination, top-off for 2 hours at 100ma, then discharge to 0.9v load voltage, then rest one hour, then charge until termination, then top off for 2 hours at 100ma, then trickle at 10ma indefinitely.


I still wonder if this method of behavior carries over into the cycle modes

 

[Black Rose]

I am pretty sure that the 2 hour top off occurs in cycle mode as well.

Charge, 2 hour rest/top-up, discharge, rest for 1 hour, repeat X times then apply final charge with 2 hour rest/top-up at the end.

 

[TakeTheActive]

I think while searching through the threads, I encountered statements that the C9000 does not top off in Refresh and Analyze mode, and also read statements that it does. In fact I believe I read two separate posts by Will Cheuh (maha rep) where one said it doesn't, and the other said it does...

Please post the LINKs so that others can read the original statements that you're referring to.

...So I just want to set the record straight here, does it or does it not top off in every mode except "break-in" and "discharge"? Or does it depend on which generation of firmware is in the unit?

It's my understanding that the "Topoff" and "Maintenance" charges are applied at 'Program Completion' for every mode except DISCHARGE:

9. When the program for a slot is completed, DONE will be displayed to the right of the bank number. With the exception of DISCHARGE mode, topoff charge and trickle charge (continuous) will be applied.

...By the way, I guess there are two possible top off points in the R&A mode. One is after the initial charge where there is a 2 hour wait before discharge, and one is after the testing is done and the battery is fully charged again. So specifics would be good...

My understanding is that "Topoff" and "Maintenance" charges are ONLY applied when DONE is displayed.

...Top off current is 100ma for 2 hours no matter AA or AAA right?

Yes.

 

[TakeTheActive]

Ok, from reading more and more threads trying to get a handle on this situation, this is my conclusion. Anyone with better knowledge please correct me.

On the original C9000 Refresh and analyze - Charge until termination, stop for 1 hour with no current, then discharge to 1v resting voltage, then rest one hour, then charge until termination, then trickle at 50ma indefinitely.

On the "improved" C9000 Refresh and analyze - Charge until termination, top-off for 2 hours at 100ma, then discharge to 0.9v load voltage, then rest one hour, then charge until termination, then top off for 2 hours at 100ma, then trickle at 50ma indefinitely...

Since I bought my MH-C9000 (0H0AA) in January 2009, I didn't pay too much attention to the original / older models. I disagree with your statements (bolded in red) on the current / improved models.

1. I understand the mid-program RESTs to be just that; no Charge or Discharge current is flowing.
2. The manual states that the 'Maintenance Charging Current" / Tricke is 10mA.

Again, please post the LINKs to your referenced material.

...I still wonder if this method of behavior carries over into the cycle modes

IME, CYCLE mode is an end-to-end linking of 66% of the REFRESH mode - i.e.

1. Charge
2. Rest
3. Discharge
4. Rest
5. ... Repeat #1-4 CYCLE # of times
6. Charge
7. Topoff
8. Trickle

 

[bcwang]

Please post the LINKs so that others can read the original statements that you're referring to.


Yes.

Ok, here it sounds like no top-off charge used during refresh:
http://www.candlepowerforums.com/vb/showpost.php?p=1766136&postcount=120

And here it sounds like yes it is used:
http://www.candlepowerforums.com/vb/showpost.php?p=2804720&postcount=273

 

[bcwang]

1. The manual states that the 'Maintenance Charging Current" / Tricke is 10mA.

Oops, you're right about the trickle current. I updated that post. I think I had too many charger specs going through my head when I wrote that. I was probably thinking of the C204w when I was writing that. I've been going through old threads trying to remember all the specifications for that charger in all modes. Of course that charger has much less interest here than these newer models.

 

[SilverFox]

Hello Bcwang,

One way to determine this for sure is to monitor the voltage of the cell during the rest period. The charge will end when the cell voltage reaches 1.47 volts (on the revised units), then, if a top of charge is being applied, the voltage will climb until the end of the top off charge.

Knowing this, you can check the voltage about a half hour after the charge part of the cycle has completed. If the voltage is above 1.47 volts, there is a top off charge being applied.

Tom

 

[TakeTheActive]

...One way to determine this for sure is to monitor the voltage of the cell during the rest period. The charge will end when the cell voltage reaches 1.47 volts (on the revised units), then, if a top of charge is being applied, the voltage will climb until the end of the top off charge...

I just checked on 4 Rayovac 1600mAh NiMHs that were nearing the end (~110-119 minutes) of their first Charge Rest Period out of a programmed 3 Cycles (700/100) and the voltages were 1.45 and 1.46, indicating to me that REST means no Topoff and/or Trickle Current was flowing.

bcwang,

Why the sudden, strong (i.e. several posts) interest in this particular aspect of the MH-C9000?

IMHO, at this point in time, it is what it is. And, it works well. What difference does it make if it 'Tops Off' between cycles? All that really matters is the final capacity displayed and that it's not damaging / overheating our cells.

 

[wapkil]

1. I understand the mid-program RESTs to be just that; no Charge or Discharge current is flowing.

I'm not sure if it's completely accurate. I haven't measured it in the rest mode but there is a low (~1.7mA) current that is applied to the battery immediately after it is inserted to the charger and after discharge, as reported in this thread.

 

[TakeTheActive]

I'm not sure if it's completely accurate. I haven't measured it in the rest mode but there is a low (~1.7mA) current that is applied to the battery immediately after it is inserted to the charger and after discharge, as reported in this thread.

I remember that thread and was actually considering referring back to it myself but eventually decided against it since IMO it would only further confuse the OP.

Also, the OP is questioning the REST periods after Charge during the REFRESH and CYCLE functions and SilverFox was questioning the DONE period after a DISCHARGE function.

...Does the C9000 switch into trickle charge mode after discharging...?

 

[wapkil]

Also, the OP is questioning the REST periods after Charge during the REFRESH and CYCLE functions and SilverFox was questioning the DONE period after a DISCHARGE function.

I know but I suspect that this 1.7mA "idle current" is present in every situation where, according to the documentation, there should be no charge or discharge current. But this is only my guessing.

 

[bcwang]

I just checked on 4 Rayovac 1600mAh NiMHs that were nearing the end (~110-119 minutes) of their first Charge Rest Period out of a programmed 3 Cycles (700/100) and the voltages were 1.45 and 1.46, indicating to me that REST means no Topoff and/or Trickle Current was flowing.

Why the sudden, strong (i.e. several posts) interest in this particular aspect of the MH-C9000?

Tom and TakeTheActive,
I don't think it's accurate to say because the voltage dropped from 1.47v down after termination, that it is not doing the top-off or trickle charge. I've seen batteries show a higher voltage during charge because of the high current, but dropping to trickle charge later the voltage slowly drops from the original terminating voltage. In fact, I've got sanyo made 2500mah cells that I've charged in my c808m, left in for a few days, and when I pulled them out of trickle they were nearly dead and with low voltage.

I'm suddenly interested because recently many of my original batteries have hit an age where things aren't looking good on this charger doing a capacity test using refresh and analyze. There are two aspects I worry about on using the c9000 to sort through my batteries.

1. If the older cells are hitting 1.47v way before they are actually full due to higher internal resistance, the discharge capacity won't be accurate. I'm hoping that the top off charge can take care of some of that if it happens. But also the fact that I know this version of the charger does not charge most cells fully when it is just done, so I'm also hoping for the top-off to take care of those for the analysis. I don't want to weed out good cells because of the incomplete charge.

2. Because the discharge current is so high, older cells that could show high capacity still at 0.2c discharge as measured on a CBA-II or a real device (400-540ma) draw which is pretty high already even for a flashlight, are showing up ridiculously low numbers on the C9000. These batteries would probably still show very good capacity when using a constant current draw and I would still use them, even though the c9000 is giving me 0mah, 100mah capacities for them.