New MH-C9000 Owner - Please advise

[Anubis12]

Anyone have a good usage guide for this charger?

This is one complex charger and the options are vast. Perhaps someone can direct me to what are some of the best settings to optimize my cells.

Here are the cells I own:

8 x AA Eneloop @ 2000maH (New Just got them)
8 x AA Rayovac Hybrid @ 2100 maH (8 months old)
8 x AA Rayovac 15 rechargeables @ 2300maH (1.5 years old)

For my initial usage, I popped in the Rayovac Hybrids in and simply let it recharge. Here are the results.

After 90minutes, the charger said all 4 cells were done, but all showed a result of ~1315maH. Huh?? I expected them to show around 2000maH. What's up? Did I miss something?

Something else interesting. I took out the cells and put them right back in just to recheck the maH. It went back to ZERO and started to recharge again. HUH?? Why does that happen?

What should I do next? I suppose the next step is to either break-in or refresh/analyze, but that goes back to my initial question, what are the best settings for all the modes.

THanks for any help!!!

 

[SilverFox]

Hello Anubis,

Welcome to CPF.

You may want to start by reading this thread.

Tom

 

[Nake]

:welcome: Anubis....isn't he a Goa'uld?

 

[Black Rose]

:welcome: Anubis....isn't he a Goa'uld?

Yep. Also the jackel headed Egyptian God.

Welcome to CPF Anubis.

 

[Anubis12]

Yep. Also the jackel headed Egyptian God.

Welcome to CPF Anubis.

Exactly

BTW, I read Tom's review and it is great information. However, it doesn't say what is the best charge and discharge rates are.

Also, it doesn't explain why the batteries do not charge to th rated power.

I did a full 'break-in' cycle on 4 Rayovac Hybrids and here are the results after 40 hours:

Cell 1 : 1944
Cell 2 : 1956
Cell 3 : 2022
Cell 4 : 1990

None are to the rated 2100mah. Is the charger not terminating properly? Do I need to do more 'break-in' cycles? Or should I run a different mode?

Maybe I am expecting too much out of the batteries? Maybe no batteries get to exactly the rated power?

I was deciding between the MH-C9000 vs. MH-C801D. I guess then the question is would the MH-C801D charge the cells exactly the same as the MH-C9000 but 8 at a time. I guess then the C801D is a better choice?

 

[Black Rose]

When I did the break-in on one of my sets of Rayovac Hybrids (last week), I got the following reported capacities:

1996, 1998, 1993, and 2006 mAh

These cells have seen one recondition cycle on my MH-C800S charger, discharged on the C9000 at 500 mA, then run through a break-in cycle.

It usually takes several cycles before the cells can reach their full capabilities.

Also, if you leave the cells in the charger for a couple of hours after the charging has finished, the charger will top them up with a trickle charge.

For charging, use the closest mA setting that is half of the rated capacity (rounded to the nearest 100 ma). i.e. 1000 mA or 1100 mA for the Hybrids.

For discharging I use either 500 mA or 1000 mA.

EDIT: The C800S that I have and the C801D you mentioned both use the same microprocessor, they just use different charge rates.
Both can charge up to 8 AA or AAA cells but they don't have as many options as the C9000. I got the C800S so I can charge my cells while the C9000 is busy with advanced tasks.
I'm not sure what generation microprocessor the C9000 uses.

 

[Mr Happy]

Also, it doesn't explain why the batteries do not charge to th rated power.

I did a full 'break-in' cycle on 4 Rayovac Hybrids and here are the results after 40 hours:

Cell 1 : 1944
Cell 2 : 1956
Cell 3 : 2022
Cell 4 : 1990

None are to the rated 2100mah. Is the charger not terminating properly? Do I need to do more 'break-in' cycles? Or should I run a different mode?

Maybe I am expecting too much out of the batteries? Maybe no batteries get to exactly the rated power?

You are indeed expecting too much. It is not at all normal to get to the rated capacity.

You could consider it like measuring gas mileage by driving a car on the freeway at a steady 40 mph without stopping or starting or going any faster. That would give you a theoretical "maximum" miles per gallon of the car, but you would never reach that figure in normal driving.

 

[Yoda4561]

Generally speaking the rated battery capacity is "slightly" overstated. It is measured under the most ideal conditions using a long trickle charge which actually overcharges the battery slightly. Compounding this is that the Maha C9000 charges to around 95% capacity due to the way it detects end of charge. The benefit is that there is almost no chance of missing the charge termination or overcharging, which drastically shortens battery life in the long term.

 

[Anubis12]

@Black Rose - Thanks for the charging clarification. Is it best to discharge completely before going into the 'break-in' cycle? The 'break-in' cycle starts off by charging the cells first.

This goes into my next question, which i haven't found the answer. After doing a full charge, I removed the cells. After a few minutes, I reinserted the same cells to 'verify' the power rating. Oddly, the MH-C9000 starts charging the cells right away. Compounding the problem, the rated mAH for all the cells starts at ZERO. What the heck? I thought this charger is a smart charger and checks the level of cells and charges from there. It seems to me that the cycle time is then started from the begining even though I already know that the cells have a high level of charge. Am I missing something?? I expect it to charge for a small amount of time and then stop and trickle. All cells have some level of charge. Very seldom is it at completely ZERO. But the charger, seems to think no matter what level the cells are at, it starts from ZERO maH.

This is troubling to me because let's say I use the cells for a few hours and then want to charge them. I would expect the time to charge is much shorter because the cells are not completely discharged. But because the charger acts in this way, I would have to wait an entire charge cycle before I can use them. Is this normal operation? Or is the charger defective?

@ Mr. Happy, I thought that might be the case. The rated power is 'theoretical' not actual.

@ Yoda4561, I did not know the MH-C9000 only charges to 95% of theoretical capacity. So, I should only expect MAXIMUM charge of 2000maH?

Sorry for all the dumb questions. Thanks for the help.

 

[Yoda4561]

That 95% is just a ballpark figure, basically it will terminate the charge just before the battery is full, but this is only for normal charging. The break-in charge is similar to the industry standard 16 hour trickle charge so those numbers should be fairly accurate. It is not unheard of for battery manufacturers to "round up" on their capacities a bit. The useful capacity of a battery is highly dependent on the discharge rate, it's possible that a different measuring tool with a slightly different rate of discharge would display a higher capacity. The C9000's numbers are accurate and consistent, but cannot be expected to match exactly with another testing device. A 2100 MAH battery is usually 1900-2050 real world with a brand new battery from a quality manufacturer. Older cells and cheap brands are often far less.

 

[Black Rose]

@Black Rose - Thanks for the charging clarification. Is it best to discharge completely before going into the 'break-in' cycle? The 'break-in' cycle starts off by charging the cells first.

This goes into my next question, which i haven't found the answer. After doing a full charge, I removed the cells. After a few minutes, I reinserted the same cells to 'verify' the power rating. Oddly, the MH-C9000 starts charging the cells right away. Compounding the problem, the rated mAH for all the cells starts at ZERO. What the heck? I thought this charger is a smart charger and checks the level of cells and charges from there. It seems to me that the cycle time is then started from the begining even though I already know that the cells have a high level of charge. Am I missing something?? I expect it to charge for a small amount of time and then stop and trickle. All cells have some level of charge. Very seldom is it at completely ZERO. But the charger, seems to think no matter what level the cells are at, it starts from ZERO maH.

It is better to discharge the cells before doing a break-in (I'm pretty sure I read that in one of SilverFox's posts on the subject).

When you reinsert the batteries into the charger, the mAh you are seeing is the mAh charge that has been applied to the cell since it was inserted.

If you watch the screen as time goes by, you'll see that the mAh number slowly increases.

The charger should detect when the cell is "full" and end the charge.

The only way to find out how much of a charge is in the battery with the C9000 would be to discharge it at 500 or 1000 mA. At the end of the discharge cycle it will report the mAh capacity of each cell.

 

[Mr Happy]

This goes into my next question, which i haven't found the answer. After doing a full charge, I removed the cells. After a few minutes, I reinserted the same cells to 'verify' the power rating. Oddly, the MH-C9000 starts charging the cells right away. Compounding the problem, the rated mAH for all the cells starts at ZERO. What the heck? I thought this charger is a smart charger and checks the level of cells and charges from there. It seems to me that the cycle time is then started from the begining even though I already know that the cells have a high level of charge. Am I missing something?? I expect it to charge for a small amount of time and then stop and trickle. All cells have some level of charge. Very seldom is it at completely ZERO. But the charger, seems to think no matter what level the cells are at, it starts from ZERO maH.

This can be explained by understanding what the charger (or any smart charger) is doing.

When you put batteries on to charge, the charger begins to charge them. It doesn't know what state of charge the batteries already have because you just put them in the charger. So in order to find out, it starts putting charge in the batteries and seeing how they respond by measuring the voltage, the change in voltage over time, and the temperature. The charger may decide, after charging for a little while, that the batteries are fully charged already and then stop charging. Or it may decide the batteries are empty and keep charging them for longer.

Either way, the charger is not magic. It has no invisible X-ray eye that can look inside a battery and see how much charge it already has. It can only charge it as if it were empty and see what happens.

This explains the mAh display. When it begins to charge the batteries this counts up from zero and displays how much charge was put in since the start. If the batteries started out empty then the mAh will count to a large value similar to the capacity of the batteries. But if the batteries were already fully charged then the mAh will count to a small value and then stop. This small value is what tells you the batteries were already charged. It means the charger only put a limited amount of extra charge in before deciding the batteries didn't need any more charging.

 

[coppertrail]

Charging Rates

1. I always do a full discharge before beginning a break-in cycle.

2. Regarding charging rates, I primarily charge at .6C and not below .5C. If I'm in somewhat of a hurry, I charge at 1C.

3. I discharge at .2C.