D cells on C-9000

[ColorMaker]

I want to test D cells on the C-9000. The D cells are rated at 10 ah capacity and the C-9000 can be adjusted to test 10 ah. I plan to solder leads to the charger battery contacts to a D cell battery holder. Will it work ?

JM

 

[SilverFox]

Hello JM,

I have never tried it, but I don't believe there would be any issues discharging D cells. Charging them is another story.

Tom

 

[ColorMaker]

Hello JM,

I have never tried it, but I don't believe there would be any issues discharging D cells. Charging them is another story.

Tom

I need the capacity feature the C-9000 offers to test the D cells.

JM

 

[Tarlach]

Charging them is another story.

Can you elaborate please? I had wondered if this was ok...

 

[jtr1962]

It should work. A better way is to connect the wires from the D cell holder to a dowel the same length and diameter as a AA cell. I did this with some C and D cell holders.

 

[Mr Happy]

The break-in mode on the C9000 has settings up to 20 Ah, so it should be able to condition and test 10 Ah cells without trouble.

I think Tom is implying that in the regular charge mode of the later C9000 firmware revisions there may be a timed cut off that will intervene before 10 Ah cells are fully charged.

 

[ColorMaker]

The break-in mode on the C9000 has settings up to 20 Ah, so it should be able to condition and test 10 Ah cells without trouble.

I think Tom is implying that in the regular charge mode of the later C9000 firmware revisions there may be a timed cut off that will intervene before 10 Ah cells are fully charged.

I am going to give it a try. It takes 48 hours to break in 2700 PowerEx What would you estimate it will take for 10A cell

JM

 

[Mr Happy]

What would you estimate it will take for 10A cell

Exactly the same. The break-in cycle consists of a 17h 45m [edit: actually 16h] charge, a 1h rest, a 5h 30m discharge, a 1h rest and a 17h 45m [edit: 16h] charge. So it takes approximately 43 [edit: actually about 38] hours to complete for all cells.

 

[Power Me Up]

Exactly the same. The break-in cycle consists of a 17h 45m charge, a 1h rest, a 5h 30m discharge, a 1h rest and a 17h 45m charge. So it takes approximately 43 hours to complete for all cells.

Except that the maximum discharge rate is 1 amp. Together with the 0.9 duty cycle for the C9000, it would take about 11 hours for the discharge part of the whole cycle...

 

[Mr Happy]

Except that the maximum discharge rate is 1 amp.

OK, that's interesting. I didn't think of that. So you think the 1 amp discharge limit applies to break-in mode as well as discharge mode? I can see it being quite believable that it does.

 

[Power Me Up]

OK, that's interesting. I didn't think of that. So you think the 1 amp discharge limit applies to break-in mode as well as discharge mode? I can see it being quite believable that it does.

Yes - I don't see why it wouldn't apply, although I haven't actually tested it to be 100% sure.

I'd say that it's a limit of the circuitry - if the limit didn't apply during a break in, you would have a 4A discharge during a break in for a 20Ah cell! The unit gets hot enough when discharging 4 cells at 1A for extended periods - I really don't think it could cope with that sort of current.

 

[TorchBoy]

Re: D cells on MH-C9000

A better way is to connect the wires from the D cell holder to a dowel the same length and diameter as a AA cell.

I remember SilverFox and one other CPFer mentioning they found that wooden dowel conducted too much for accuracy (or safety, or something).

The break-in cycle consists of a 17h 45m charge, a 1h rest, a 5h 30m discharge, a 1h rest and a 17h 45m charge.

What happened to a 16 hour charge? Mine stops after 960 minutes.

 

[SilverFox]

Re: D cells on MH-C9000

Hello Ian,

The issue with wood is that it can soak up moisture. If you are in a dry climate, no problem, but if you are in a moist climate...

The actual Break-In charging time is 16 hours, but the discharging time depends on the capacity of the cell and what you used for your values when you set the cycle up.

Tom

 

[Mr Happy]

Re: D cells on MH-C9000

What happened to a 16 hour charge? Mine stops after 960 minutes.

You are right, I was mistaken. Even so, things are not quite as expected.

If you carefully measure the C9000 against an external reference you will find that when the display says 960 minutes or 16 hours during a break-in cycle, the total charge supplied is not 1.6 C as expected, but only 1.44 C.

Similarly, the charging and discharging currents on the C9000 are not quite as displayed either. When the display says the charging current is 1000 mA, the time-averaged charging current is 900 mA; when the display says the discharging current is 500 mA, the average current is 450 mA. Again you can check this with an external clock: look at how fast the mAh totals increase compared to the amount of actual time that has passed and you will see it is as I say.

So when the C9000 does a break-in cycle, it actually does a 0.09 C charge for 16 hours up to 1.44 C total charge, and a 0.18 C discharge down to the end voltage taking about 5.5 hours if the capacity is as expected. As Tom says, the actual time taken for discharge depends on the real capacity of the cell. It will take more or less time according to whether the real capacity is more or less than the entered capacity in the set up.

Why the funny numbers, you ask? Well, Power Me Up knows. It's because the C9000 works on a 0.9 on/0.1 off duty cycle. It's only 'working' for 0.9 out of every 1 second. This means that all indicated currents on the C9000 need to be multiplied by 0.9 to get the true figure. However, indicated times are accurate, and the accumulated mAh totals are accurate as well since the C9000 internally allows for the 0.9 factor in its adding up.

 

[TorchBoy]

Re: D cells on MH-C9000

I've just run four slow charges in a row on a set of Eneloops, and every one of them ended after the expected 16 hours. If what you say is right the whole lot would have taken seven hours longer than I thought it did. Am I really that bad at keeping track of time? I wondered why I got hungry toward the end...

j/k

Seriously, the first slow charge actually ended ten minutes before the 16 hours. I figured I could live with that.

I think you might have it the wrong way around - I reckon it charges 90% of the 16 hours, not charges for 16 hours but only 90% of the time.

 

[TorchBoy]

Re: D cells on MH-C9000

No, seriously, Mr Happy, did you never wonder why your MH-C9000 puts 2880 to 2890 mAh into an Eneloop while slow charging it? The first of April was a couple of weeks ago! :thumbsdow

 

[Mr Happy]

No, seriously, Mr Happy, did you never wonder why your MH-C9000 puts 2880 to 2890 mAh into an Eneloop while slow charging it?

I corrected my post above. I think I have my facts right now.

I just put a cell on break-in with an entered capacity of 2000 mAh.

After 60 minutes on the stopwatch the C9000 also said 60 minutes. However, the accumulated mAh was 180 (= 200 * 0.9) rather than the expected 200. :duh2:

When the charge completes after 960 minutes, the total charge will be 1.6 * 2000 * 0.9 = 2880 mAh, rather than the expected 3200 mAh. :shakehead

This is probably harmless, but it is rather curious. It means if you want your 2000 mAh cell to really get a 0.1 C charge for 16 hours, you should enter the capacity as 2200 mAh rather than 2000.

 

[TorchBoy]

Re: D cells on MH-C9000

It means if you want your 2000 mAh cell to really get a 0.1 C charge for 16 hours, you should enter the capacity as 2200 mAh rather than 2000.

:thinking: That would mean it would be charging at 220 mA for 90% duty cycle, so you'd need a really big capacitor across the battery to even it out.

 

[SilverFox]

Re: D cells on MH-C9000

Hello Mr Happy,

Another variable to consider is that the actual capacity of the cell may not be as high as the labeled capacity.

With some cells, the actual capacity comes in at around 90% of the labeled capacity, so everything evens out.

Tom

 

[ultrajr]

Hi,
I have been contemplating a C-9000 for a a while now, my battery collection has grown to the point where I need to start managing my cells better. I had seen a recent post where I THOUGHT the person indicated he was charging C/D cells using this charger. Is it just a matter of placing the cell into a batter holder and taping the leads to a dowel or something (cut to the same length as an AA) that won't conduct electricity and inserting that into the charger?
This would nail the deal for me, sounds like it would be a great upgrade from my Maha c204W AA charger.