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09-09-2012, 08:47 AM   #1
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Battery Question for UnknownVT??

Hi all, and hopfully UnknownVT,

I finally decided to purchase a Powerex MH-C9000 WizardOne Charger, and to be honest, it was all going well until I started reading the instructions....
I Decided not to knacker any of my Eneloop's but wanted to do a test with a couple of Vivanco 2400 1.2V AA MaH NiMH's I've got knocking about that I could try the new charger out on. (It's only 2 Batteries being tested/recharged).

I'm really hoping that you have some knowledge of this particular charger. from the instructions, I gathered that it would be best to use the 1st and 4th slots, for the charge I want to use, I was going to try the "Refresh & Analyze" "for one to three times" mode.

But this is where my calculations go awry,

Following the instructions:
---------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity Storage Memory: 12 (Cycle mode only)

supported capacity: * 100 to 20,000mAh ----------------------- (I think the only one I need to be interested in)

Charger Input power: 12V 2.0A

Adapter Input: 100-240v 50/60Hz

*ALWAYS ENSURE THAT THE BATTERIES CAN ACCEPT THE PROGRAMMED RATES.
------------------------------------------------------------------------------------------------------------------------------------------------------

General Battery Education:
What is 0.1c, 0.2c, ect?

"C" stands for the battery capacity and the number preceeding 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 0.3C 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.
As for the discharging rate, do not exceed 1.0C.

The instructions then go on about "Battery Matching" and Battery Forming" and a whole load of more info.

So far it almost sounds like I know what I'm doing until I looked at the batteries I was going to use.

On the side of the batteries it states:
Standard charge: 14hrs at 220mA
Rapid Charge: 1.4hrs at 2400mA

Would you be kind enough to give me some guidance as to what I should set the charger at for these batteries.

Shortcut for instructions: http://www.mahaenergy.com/download/mhc9000.pdf

Thanks chaps for taking the time to read this,
all the best
sadsack.

09-09-2012, 09:06 AM   #2
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The main thing is not to over-heat the batteries and shorten their life.
The default ( no button pushing required ) MAHA C9000 charging rate of 1000mA=0.5/C is fine for Eneloops. The 0.37/C rate should be fine for your 2700mAh batteries also.

Last edited by Ex Finn.; 09-09-2012 at 09:12 AM.
09-09-2012, 09:25 AM   #3
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Thanks Ex Finn,

But Eneloops are only rated at 2000 mAh, so as long as they are not rated as "normal" or "fast charge" 2000mAh should equal 200mA at 0.1C.

This is where it becomes a little complicated, as per the instructions:

"Charging at a rate below 0.3C and above 1.0C is not recommended".

So if I take the instructions for granted it would be best to take the lowest number I.E. 0.3C So for Eneloop's 0.3C x 2000mAh would be 600mA

I cannot find anywhere on the instructions where it states a default charging rate. It doesn't even mention it on the box it came in.
09-09-2012, 10:16 AM - 1 Like   #4
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"Charging at a rate below 0.3C and above 1.0C is not recommended".

0.3/C = about 600mA and 1.0/C = 2000mA, so staying above the minimum and below the maximum is what we want.

Insert one of the Eneloops in the charger and just observe the display, it will blink "MODE" and the arrow will be pointing at the "CHARGE".
Do nothing and the MAHA will start charging at 1000mA rate, perfectly fine for staying above minimum and below maximum charge rates.

Cheers.

p.s. from the owners manual "When a new battery is detected, the LCD will display an arrow below
the bank number and prompt for the mode by flashing “MODE”.
Use the UP and DOWN arrow keys to choose the desired mode.
Press ENTER to make the selection.
If no key is pressed within five seconds, the charger will proceed to
the default mode which is charging with 1000mA rate."


Last edited by Ex Finn.; 09-09-2012 at 10:22 AM.
09-09-2012, 10:42 AM   #5
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Thanks Ex Finn,

but as I mentioned in the first part, I am not testing Eneloop's at the moment, i am doing a trial run on a pair of Vivanco 2400 1.2V AA MaH NiMH's, which has:

On the side of the batteries it states:
Standard charge: 14hrs at 220mA
Rapid Charge: 1.4hrs at 2400mA
on the side of them.

One unit is showing as completely dead on a tester, the other shows a minimum of juice that very quickly deteriorates.
09-09-2012, 12:30 PM   #6
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You may take a look at NLee the Engineer's review and faq on Amazon. Well worth reading, IMO.

Amazon.com: NLee the Engineer's review of PowerEx MH-C9000 WizardOne Charger-Analyzer
Amazon.com: NLee the Engineer's review of Maha PowerEx MH-C9000 Wizard One AA/AAA Ba...

Last edited by sherwood; 09-09-2012 at 12:34 PM. Reason: mistake
09-09-2012, 12:49 PM - 2 Likes   #7
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QuoteOriginally posted by Ex Finn. Quote
"Charging at a rate below 0.3C and above 1.0C is not recommended".
Ex Finn is so right on this -
a lot of people think that slow/lower charge currents are kinder to batteries -
this is just not so -
most experienced battery people charge at an "optimal" current of 0.5C - in the case of eneloops is 1000mA -
which happens to be the default charge current.

As Ex Finn nicely put it - charge AA eneloops at 1000mA.

Now to do the next bit -
I always use my eneloops in the K-x until they are literally depleted - ie: the camera shuts down - sometimes more....
er... how?
well, inevitably the camera shuts down when I'm just about to shoot - and the "emergency" measure is to turn the camera off then back on again - this can even be done without removing the camera from eye-level. The camera will normally power up ready to shoot. So that's how I get a few shots beyond the first shut-down. I then change the batteries as soon as I can - not just because it may not be so good for the batteries - but more because it is darned inconvenient to shoot that way.

OK, this brings us (finally) to the point - I then always discharge my batteries when I get home with the Maha C9000 - at the standard discharge rate of 0.2C = 400mA - I do this mainly to check the remaining capacity - and secondly to re-assure myself that I haven't inadvertently deep-discharged any.

The Maha/PowerEX C9000 is IMHO the best consumer grade battery charger - I know many will also cite the LaCrosse - but the last time I checked even their top of the line Alpha charger is not that flexible on discharge currents. For a 400mA (=0.2C of eneloop) the follow up charge current is then 800mA - if you want 1000mA charge current - then then discharge has to be at 500mA - not flexible enough to get the ideal.

My C9000 seems to charge up position 1 (left-most) the least - in order of highest to lowest charge mine seems to be 3,2,4,1 - but this is NOT reliable - as it is so dependent on the battery. However position 1 (left-most) seems always to be consistently just a bit lower on my copy.

My charging regime is to always discharge at 0.2C = 400mA until done - then let batteries rest overnight then charge at 0.5C = 1000mA until done then allow the eneloops to sit in the charger for another 2 hours for the top-up charge.

I cycle 3 sets (of 4) - one in camera, carry spare set - one set at home. Before moving the set which was at home to the spare carry set I do a quick top-up charge @ 1000mA - until "done" - before putting them in the bag.

I have now used eneloops in my K-x for almost 58,000 shots with over 49 changes of battery and I average over 1,200 shots per charge with my last two counts at: 1,433 and 1,375 - normally no flash and no live-view or movies.

As for your Vivanco 2400 1.2V AA mAh NiMH -
discharge at 0.2C = close enough to 500mA - until done; wait for at least 1 hour - then charge at 0.5C = 1200mA until done, and allow the batteries to sit in charger for another 2 hours -
see if they then hold charge and work OK -
if not then run them through the Maha C9000 refresh cycle - be warned this can take a long time.

[Personally - I'd stick to eneloops for any Pentax dSLR - regular non-LSD batteries just do NOT work that well - also eneloops are better than almost any other LSD too - that is why they are so recommended here)

Hope that helps

Last edited by UnknownVT; 09-09-2012 at 01:15 PM.
09-09-2012, 01:31 PM   #8
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Powerex batteries by Maha are also very good and last a good deal of time. They hold charge well also. I've had good experience using multiple sets of this brand of battery.

09-09-2012, 02:08 PM   #9
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I would just like to say thank you to all, who have read and helped me with my new charger, I wasn't expecting it to be quite as complicated as it is, but like everything, I think once I've done a few charge/discharges it will be like second nature.
I had to give up on the vivanco, It didn't seem to matter what I did with this spare pair, they both showed as "HIGH", (They was only for my boy's Wii, so no real hardship).

Thanks to Ex Finn, Sherwood, Ash, & UnknownVT, Thank you for the links, and (Don't laugh) I'm going to have UnknownVT's info laminated for reference.

The one thing I have been doing, and I'm not too sure why,.... It just seemed like the right thing to do, but I've been keeping each set of four Eneloops I have together, and doing my best not to mix them, honestly don't know if it helps, but not having a descent charger I wouldn't know if one battery was weaker than the other three anyway. Hopfully the C9000 will remedy that.
Thanks again chaps...
sadsack
09-09-2012, 02:37 PM   #10
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QuoteOriginally posted by sadsack Quote
The one thing I have been doing, and I'm not too sure why,.... It just seemed like the right thing to do, but I've been keeping each set of four Eneloops I have together, and doing my best not to mix them, honestly don't know if it helps, but not having a descent charger I wouldn't know if one battery was weaker than the other three anyway. Hopfully the C9000 will remedy that.
Even better is to mark/number each battery
so you can keep track of them individually.

Last edited by UnknownVT; 09-09-2012 at 08:52 PM.
09-10-2012, 06:12 PM   #11
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I honestly don't know why I didn't think of that, at least I can throw away the elastic bands now......

Thanks UnknownVT...

sadsack..
09-10-2012, 06:34 PM   #12
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QuoteOriginally posted by sadsack Quote
I honestly don't know why I didn't think of that, at least I can throw away the elastic bands now....
Keep those elastic (rubber) bands -
they always come in handy

Once you've numbered/marked the individual batteries uniquely -
the option opens in tracking their individual performance.
(total charge input+time; remaining (dis)charge+time -

even from fully charged (0.5C = 1000mA charge to Done + extra 2 hours on top-up charge)
discharge at 0.2C = 400mA til Done to see the actual/real capacity.

Enjoy your new (versatile and powerful) toy!

Last edited by UnknownVT; 09-10-2012 at 08:44 PM.
09-11-2012, 02:41 AM   #13
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Hi UnknownVT,

Decided to try and recover some AAA 1000mA Energizers, Two of which showed on a test meter as being totally dead, two showed as being almost fully charged.
So I thought, seeing as they have never really been properly charged separately I would pop all 4 in and do a "Refresh & Analyze".

This is where some strange things started to happen, the two that showed as dead, started to go through the R & A, the two that were showing nearly full showed that they were "HIGH" or dead.
This didn't make a lot of sense, and I also noticed that the first slot kept loosing the battery, I.E. as if it wasn't even inserted, .... after a bit of head scratching I decided to just gently turn the battery in the first slot and once again it asked me what I wanted to do with it, (like I had just put it in). This occurred three times. Now I know I made sure I put the batteries in properly following the AAA guidelines in the instruction sheet, and the battery was fully engaged.
(This wouldn't be the first time as I have had to do a similar thing with my energizer charger as well).
After calming down, and having thoughts of dragging said sales person over the counter & gently requesting my money back, I thought I would give it one more go, So now the two batteries that were showing dead are going through an R&A, one that was showing as almost fully charged is going through a "Discharge" and the other that was showing as almost fully charged is going through an R&A, within 30 minutes the three that were set on R&A are already on "Rest" and the other is still on discharge.
All of them were set on the charger default of 1000mA and the discharge at 500.

I am hoping that once the discharged battery had depleted I am going to do a R&A on that one as well.
It doesn't surprise me that the batteries are in such a state as they have been on and off different chargers even including the Wii remotes that come with AAA converters to charge on there own stand.
Has any one had a similar problem with batteries not making a good contact on chargers or is it just my luck, (Luck is not on my side this year, Three times in A&E, one hit & run, a torn gastrocnemius not including whiplash as well.
and my mates say I worry to much.

thanks chaps
sadsack
09-11-2012, 08:26 AM   #14
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QuoteOriginally posted by sadsack Quote
Decided to try and recover some AAA 1000mA Energizers, Two of which showed on a test meter as being totally dead, two showed as being almost fully charged.
All of them were set on the charger default of 1000mA and the discharge at 500.
...
and my mates say I worry to much.
Don't wish to worry you -
but those are AAA batteries which have substantially lower C (=capacity) than AA batteries.
those C = capacity = 1000mAh

So the optimal charge current 0.5C = 0.5x1000 = 500mA
the standard discharge current = 0.2C = 0.2x1000 = 200mA

Your charge current is 1000mA = 1000/1000 = 1.0C - this is marginal -
it is only just within the guideline - and most 1000mAh AAA tend to be "optimistically" rated.
Your discharge current is 500mA = 500/1000 = 0.5C - this is too high.

Old batteries usually need their contacts cleaned -
setting the batteries in the charger and rotating them back and forth a little - usually mechanically "scuffs" them a bit, and ensures good contact.

Still if they are managing to go through R&A cycle - hopefully you may have managed to resuscitate them,
and not just somehow managed to "trick" the charger to go through the process.

Last edited by UnknownVT; 09-11-2012 at 09:10 AM.
09-11-2012, 10:29 AM   #15
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This is why I'm don't mind testing some old units first.... (No wonder why these 4 AAA went through an R&A so quickly).... lol

Here is what the charger says at the moment,

Slot 1: --------------- Slot 2: ------------------ Slot 3: --------------- Slot 4:

724mAh ------------- 742mAh --------------- 784mAh ------------- 869 mAh
95 min --------------- 97 min ----------------- 102min --------------- 114min (these are obviously going up all the time as the units are still attached).
1.43V ---------------- 1.43V ------------------- 1.43V ---------------- 1.44V

R&A only ---------- R&A only ------------Discharge ------------ R&A only
-----------------------------------------------------then R&A

I do believe it was only a contact issue as they went through the process without a hitch, apart from my miscalculations of course, and also that two were dead to a meter and two were semi charged, in fact slot 3 was one that had the most charge.
What do you think of these measurements, they have only been through one R&A apart from slot 3, and I did read in the instructions that it is possible to do more than one R&A to bring batteries back to near there original state.
Also thank you for the information to the proper charging amounts for these AAA's.

Thank you again UnknownVT..
sadsack

another quick edit....

the times have not changed at all, my mistake.... (I only thought they would)

slot 1 everything the same
slot 2 everything the same
slot 3 gone up to 145v
slot 4 gone up to 145v

Last edited by sadsack; 09-11-2012 at 10:41 AM.
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