MH-C9000 and Eneloops charge rate

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z_Dry-cell

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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.
 

Dry-cell

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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.
 

s0lar

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

Dry-cell

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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.
 

mrlysle

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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.
 

Dry-cell

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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.
 

mrlysle

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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! lovecpf
 

Dry-cell

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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?.
 

Russel

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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?
 

Russel

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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.
 

Dry-cell

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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.
 

mrlysle

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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!
 

Dry-cell

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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.
 

Russel

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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.
 

Mr Happy

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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.
 
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