# Thread: MH-C9000 and Eneloops charge rate

1. ## MH-C9000 and Eneloops charge rate

Hi guys, I ordered a Sanyo Eneloop 4 Pack AA NiMH Pre-Charged Rechargable Batteries w/ Charger (SEC-MQN064) from Amazon. http://www.amazon.com/gp/product/B000IV0REA

I also bought a pack of AA and AAA pre-charged Eneloops (4 pack). Not long after I decided to purchase the Powerex MH-C9000 charger, in order to prolong the life of the Eneloops and my other rechareable NiMH batteries.

The SEC-MQN064 only charges batteries in pairs and cant tell me if a battery is dead.

Like I said before, I want to prolong the life of the batteries. When I go to charge the batteries, I want to use the longest charge time 200mAh. Based on the capacity of the AA and AAA Eneloops. Is this safe for them to be charged at this rate or should I use 500mAh or 1000mAH?.

Taken from the MH-C9000 pdf manual...

GENERAL BATTERY EDUCATION

What is 0.1C, 0.2C, etc?

“C” stands for the battery capacity and the number in front of it is the

fraction of the battery capacity. For example, 0.1C means 0.1 times the

capacity for the battery. For a 2700mAh battery, 0.1C would be 0.1 times

2700mAh which equals 270mA.

Choosing the right charging discharging rate

Charging at a rate below 0.33C and above 1.0C is not recommended.

Charging too slow may prevent the charger from terminating correctly.

Charging too fast may damage the battery.

Typically speaking, slower charging rate will yield better battery

performance but requires longer time. Faster charging rate may not

charge as fully and battery temperature can be higher.

2. ## Re: MH-C9000 and Eneloops charge rate

About discharge rates for NiMH. I know you should discharge NiMH @ 0.2 x the capacity of the battery. So, discharging the AA's @ 0.2 x 2000mAh=400mAh. But when you calculate the AAA's @ 0.2 x 800mAh=160mAh. I'm pretty sure I should discharge them @ 200mAh since the MH-C9000 doesn't have that setting, correct?.

I haven't yet received my MH-C9000, still eagerly awaiting.

3. ## Re: MH-C9000 and Eneloops charge rate

I discharge my AA's at 300-700mAh. My AAA's at 200-500mAh.

4. ## Re: MH-C9000 and Eneloops charge rate

I'd like to keep it at industry standards and not muck up my batteries. They're brand new, how long does a discharge for AAA take @ 200mAh?. Also, how long does a discharge rate of 400mAh for the AA's take?. Just curious.

5. ## Re: MH-C9000 and Eneloops charge rate

Hi Dry-cell. If you look on Maha's website, there's a FAQ section with some very helpful info in it. You are correct however to discharge your AAA's at 200ma. Maha instructs that when you have a cell that doesn't match any of the pre-set settings, to just "round up" to the next level. So for the 800mah rated AAA's, dis-charge @ 200ma and charge @ 400ma.

6. ## Re: MH-C9000 and Eneloops charge rate

Originally Posted by mrlysle
Hi Dry-cell. If you look on Maha's website, there's a FAQ section with some very helpful info in it.
Ah, thanks mrlysle. I hadn't looked in the support section, but I have everything else printed out about the charger. The pdf manual, specs, features and a few threads from CPF.

Sorry if I'm slow to post, I have to have admin approve them first.

7. ## Re: MH-C9000 and Eneloops charge rate

Originally Posted by Dry-cell
Ah, thanks mrlysle. I hadn't looked in the support section, but I have everything else printed out about the charger. The pdf manual, specs, features and a few threads from CPF.

Sorry if I'm slow to post, I have to have admin approve them first.
Hey buddy, no prob! I had to go through it all again today myself! Lost my "flashaholic" status in the "crash"! It's all good though. I'm just glad CPF is back up and running. I've already learned some GREAT stuff just this afternoon I'm excited about. This is the best forum in the world!

8. ## Re: MH-C9000 and Eneloops charge rate

Amen to the best forum!!!

9. ## Re: MH-C9000 and Eneloops charge rate

I have my charger now, and have my AA Eneloops on Refresh and Analyze. I removed my Fellows six plug surge protector Model #99109, and plugged it directly to the wall outlet. Will the surge protector cause problems with the MH-C9000?.

10. ## Re: MH-C9000 and Eneloops charge rate

The only real difference that I would expect is protection from surges, if you plug your charger into the surge protector. Has anything lead you to believe that using a surge protector is bad?

11. ## Re: MH-C9000 and Eneloops charge rate

I just thought that it may mess up termination, or something to due with the microprocessor.

12. ## Re: MH-C9000 and Eneloops charge rate

If anything, it should protect the charger from surges. I usually run my MH-C9000 chargers from a solar power system with the voltage fluctuating
anywhere from 12.5V to 14V and have never had that cause a problem. The few times that I've used the external power supply that came with the C9000 charger, I plugged it into a surge protector or a UPS, not because I was worried about the house power, simply because those were the convenient places to plug in for power.

Heck, I just had one C9000 running continuously for the last several days performing break-in cycles on 16 new Eneloop batteries that I just got. I perform a break-in on new batteries, after which I run cells through the break-in cycle once a year. During the time of year that I run a couple dozen cells through break-in I've got two chargers working around the clock. Never once have I had a problem with the C9000 charger “glitching” in any way shape or form. Of course, I could say that about my other chargers as well, a MH-C808M, a BC-900, and a BC-700.

I don't think you have anything to worry about. Plug your charger into the surge protector if it is convenient, or plug it directly into the wall. I wouldn't worry either way.

I do recommend using a safe surface to charge on, and not leaving the charger unattended while charging. I use a counter top remnant (quartz composite) about 2' by 3' to charge on, with a smoke detector above. Personally, I'm not always in the same room as the charger when it is on, but I'm always in ear shot of the smoke detector. If I have to leave the house, I shut the charger off.

13. ## Re: MH-C9000 and Eneloops charge rate

Thank's for the piece of mind Russel.

I have the charger in my bedroom and it's sitting on top of a plastic file box on the floor with the chargers stand out to keep it cool. I have it away from the wall. Their's a smoke detector nearby, but I always monitor my chargers anyway. The surge protector I use for my computer. The charger is very quite, I don't hear it at all.

14. ## Re: MH-C9000 and Eneloops charge rate

Dry-cell. If it was me, I'd plug that sweet new charger into a surge protector! It won't affect the operation of the charger one bit, except PROTECT it! Grats on your new charger! They really are great units!

15. ## Re: MH-C9000 and Eneloops charge rate

Yeah, I'm going to use it next time. I was just being carefull, that's all. Thanks for the help guys.

16. ## Re: MH-C9000 and Eneloops charge rate

My very first end results with the MH-C9000 and 4 AA Sanyo Eneloops (old).

Refresh and Analyze

Slot 1: 1799 mAh, Min 232, Volt 1.44

Slot 2: 1778 mAh, Min 234, Volt 1.44

Slot 3: 1792 mAh, Min 232, Volt 1.44

Slot 4: 1758 mAh, Min 230, Volt 1.43

Their all below minimum of 1900. These are dated 2009 and were the second pack I received. I'll use them for my Wii Plus remote.

The other 4 AA's I got with the cheap Sanyo charger (SEC-MQN064), and are dated 2010.

17. ## Re: MH-C9000 and Eneloops charge rate

Dry-cell, what charge rate did you use with refresh and analyze of your cells above? I'm assuming you discharged at 400mA after reading your previous posts.

18. ## Re: MH-C9000 and Eneloops charge rate

Charge: 1000mA Discharge 500mA

19. ## Re: MH-C9000 and Eneloops charge rate

Those are good rates for Eneloop cells.

20. ## Re: MH-C9000 and Eneloops charge rate

Originally Posted by Dry-cell
Their all below minimum of 1900. These are dated 2009 and were the second pack I received. I'll use them for my Wii Plus remote.
Those results are fine for a refresh/analyze test. You might find they increase slightly with another cycle, but it is normal to see slightly lower numbers when using refresh/analyze on the C9000 since it does not attempt to stuff the maximum charge into the cells.

If you want to get a more accurate indication of the capacity you need to run a break-in cycle. That is designed to get close to the industry standard test cycle that battery capacities are quoted from.

A good rule of thumb is that the number printed on the side of the battery does not mean you will always see that capacity out of the battery.

21. ## Re: MH-C9000 and Eneloops charge rate

I'm sure their better than the results I would get from the Sanyo charger, right?. 39 to 45 hours to complete seems a bit much. I put them through the Refresh and Analyze because it takes several charge and discharges to reach close to the capacity of the battery.

22. ## Re: MH-C9000 and Eneloops charge rate

Originally Posted by Dry-cell
I sure their better than the results I would get from the Sanyo charger, right?. 39 to 45 hours to complete seems a bit much. I put them through the Refresh and Analyze because it takes several charge and discharges to reach close to the capacity of the battery.
Personally, I wouldn't be concerned. Just use the batteries and don't worry about it. The capacity on the battery is a "theoretical" number, not a "this is what you will actually get" number. My Eneloops also give about 1800 mAh on Refresh/Analyze. Once I know this number, it becomes my benchmark for future tests. So in future, if I saw 1700 mAh that used to be 1800 mAh I would know the battery is fading.

23. ## Re: MH-C9000 and Eneloops charge rate

I keep my batteries in a new clear case for tool bits, fishing lures, and such, you know the ones with the seperators. That way I can keep them in pairs and have them matched together.

24. ## Re: MH-C9000 and Eneloops charge rate

I have two MH-C9000s and have charged about 40 AA Eneloops many times over the last several years. I have always set the charge current at 600mA. So far all of the batteries are still in excellent condition.

I recently purchased some Eneloop 1500s and Apple LSD batteries. Here is how they tested in the Break-In Mode.

The capacity (mAh) of the Eneloop 1500 batteries tested as follows:
2081.2088, 2089, 2084, 2082, and 2076 Average = 2083.3 Std. Dev. = 4.4

The capacity (mAh) of the Apple LSD batteries tested as follows:
2065, 2078, 2053, 2077, 2054, and 2077 Average = 2067.3 Std. Dev. = 10.7

Both the Eneloop 1500 and Apple LSD batteries tested at slightly higher capacity than the standard Eneloop AAs. Most of those tested at 1950 to 2000 mAh. All Eneloop batteries I own have met specifications when tested in the Break-In Mode on the MH-C9000.

25. ## Re: MH-C9000 and Eneloops charge rate

Dry-cell. I know it's a long process but I'm sure you'll end up with a higher mah reading after doing a "break-in" cycle on your new C-9000. All of my Eneloops have come out OVER their rated capacity after a break in cycle! The AA's all show over 2000 mah, and my AAA's all show over 800 mah. For instance, the last break in I run on a package of AA's gave me 2088, 2076, 2055, and 2073 mah. BTW, these were "brand new" "never used" Eneloops. I dis-charged them first, then run a "break-in" cycle on them, but I'm confident you would get the same results on cells that had been used several times before running the "break-in" cycle. "Break-in" cycle is the best cycle to use on the C-9000 if you want to see max capacity from your cells, but like others have said, don't worry too much about it yet. Just charge up a couple sets so you have something to use in your lights, and while your enjoying them, go ahead and run a "break-in" cycle on a few. It does take FOREVER so only run it when you've got some charged and useable. You won't hurt them just by charging them, even if they weren't completely dis-charged. That's what is soooo nice about the LSD Eneloops. They're top performers in my book and your new C-9000 will really make them "shine"! (pun intended)

26. ## Re: MH-C9000 and Eneloops charge rate

One reason the refresh/analyze gives result around 1800mAh istead of 2000mAh could be that you do not fully charge the batteries with the MAHA C-9000.
As I said before, the charge termination is often done at 1.48V instead of at the -dV point. It terminates charging prematuraly. In the end it will give you more cycles but slightly lower performance.
The MAHA C-9000 continues to charge at 100mA for 2 hours after fast-charging is terminated. By removing the cells right after the fast-charge you can then easily see in a test that the cells are not yet fully charged.
Reading the mAh that went in and multiplying by 0.9 will give you an approximation of the capacity inside the cell.

27. ## Re: MH-C9000 and Eneloops charge rate

I left the batteries in the charger the full time until it said done for each cell (Charge/Rest/Discharge/Rest/Charge). I then wrote down the results for each battery, then removed each one before unplugging the charger. I put them away in the storage case afterwords.

Do you guys use your batteries strait out of the charger, or do you let them rest a certain period of time?.

28. ## Re: MH-C9000 and Eneloops charge rate

Originally Posted by Dry-cell
Do you guys use your batteries strait out of the charger, or do you let them rest a certain period of time?.
Hi Dry. You can do it either way. Cells fresh off the charger will yield slightly higher capacity, as even LSD cells loose a bit of their capacity soon after removing from the charger.

On the subject of discharging cells at different rates, such as refreshing using a 500mA discharge rate vs. "breaking in" using a 400mAh rate, the slower the discharge rate, the higher the capacity will be. That is to say that the same cell discharged at a 500mA rate, will always result in less capacity than if the same cell were discharged at a 400mA rate. This is because at slower discharge rates, the cell is actually discharged farther than at higher rates, due to the cell voltage remaining higher for longer at low discharge rates, thus effectively allowing a deeper discharge.

Dave

29. ## Re: MH-C9000 and Eneloops charge rate

Thanks for the info 45/70. I chose a 500mA discharge due to the chart below, I was going to use 400mA to begin with (0.2 x 2000mAh =400mA). I can always do it next time.

http://www.mahaenergy.com/store/mhc9000faq.asp
What are the recommended charging and discharging current for my battery?

The recommended charging current is 0.5C, or 0.5 times the battery capacity. The recommended discharging current is 0.25C, or 0.25C times the battery capacity. Here are some settings for common batteries:

2700mAh Charge: 1300mA Discharge: 700mA

2650mAh Charge: 1300mA Discharge: 700mA

2500mAh Charge: 1200mA Discharge: 600mA

2300mAh Charge: 1100mA Discharge: 600mA

2200mAh Charge: 1100mA Discharge: 600mA

2100mAh Charge: 1000mA Discharge: 500mA

2000mAh Charge: 1000mA Discharge: 500mA

1000mAh Charge: 500mA Discharge: 200mA

900mAh Charge: 400mA Discharge: 200mA

850mAh Charge: 400mA Discharge: 200mA

800mAh Charge: 400mA Discharge: 200mA

700mAh Charge: 300mA Discharge: 200mA

650mAh Charge: 300mA Discharge: 200mA

600mAh Charge: 300mA Discharge: 200mA

30. ## Re: MH-C9000 and Eneloops charge rate

I should have asked this before I started another Refresh & Analyze on my other 4 new AA Eneloops. Like the Break-in mode, do you guys recommend a discharge prior to running a Refresh & Analyze?. If so, how long do you rest the batteries after discharging them before running the Refresh & Analyze mode?. This time I'm discharging @ 400mA instead of 500mA.

The batteries are going to be used in my new flashlight that's coming soon, and my digital camera.

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