Initial charge on Eneloops, charging strategies.

[Muse]

is there a v36? It's either 35 or 36 I can't recall, but it's not 32 if that's what you were getting at.

How can you tell which version you have?

 

[TakeTheActive]

Re: Initial charge on Eneloops (AAA)

...Edit: As long as you charge at the recommended rate of .5C to 1C or 400ma to 800ma with the BC-900 and your 800mah AA cells, using your cooling fan shouldn't be a problem.

😳​

If not a problem for AA cells, I'd think it wouldn't be a problem for AAA cells either at those charge rates with the cooling fan on...

I'm fairly confident that 'AA' was just a typo and Russel meant 'AAA' - I'm not aware of any 'recent production' 800mAh NiMH AA cells.

 

[TakeTheActive]

Re: Initial charge on Eneloops (AAA)

The BC-900 has 3 methods to monitor charge:
1) -delta V
2) max temp (It will just pause, not end for high temp)
3) max V...

4 Methods: 🙂

1. -DeltaV - Terminate
2. Max Voltage - Terminate
3. Max Temp - Pause
4. Max Time - Terminate

 

[TakeTheActive]

Re: Initial charge on Eneloops (AAA)

I've only had my BC900 for a couple months now, but I worry about the temperature as well when charging above the neighborhood of .3C...

IMHO, you're hanging out in a BAD NEIGHBORHOOD. 😱 Move to 0.5 - 1.0C and you'll feel MUCH safer... :grouphug:

...For example last night I charged a pair of newly discharged eneloops at 1000 mA. They got warm by 1 hour into charging, and continued to get hotter throughout the remainder of the charge. The were not so hot that I could not touch them, but it was kind of like cupping your mug of fresh hot cocoa...

Buy yourself an inexpensive digital thermometer with a remote probe like the RadioShack one Russel shows in his photo. I have an older RS model and you'll be surprised how HOT 😡 a STILL safe 120ºF :wave: feels to the touch.

 

[TakeTheActive]

Re: Initial charge on Eneloops, charging strategies. (AAA)

...I was just wondering because I keep staring at this charger over at the ThomasDist. website 🙂

[OPINION]

• If you've been using rechargeable cells for YEARS and already have a stockpile of (possibly / most likely) CRAP cells, buy the BC-900 first and then get the MH-C9000 when funds allow (and you can also buy new LSD cells).
  .
• If you're a "Rechargeable Cell Newbie", just starting out, with a stockpile of NEW 'vibrant' LSD cells, buy the MH-C9000 first and then get the BC-900 when funds allow (and your original new LSD cells are approaching CRAP).

[/OPINION]

 

[Russel]

Re: Initial charge on Eneloops (AAA)

😳​

I'm fairly confident that 'AA' was just a typo and Russel meant 'AAA' - I'm not aware of any 'recent production' 800mAh NiMH AA cells.

You are correct! Thanks for pointing that out: 800mah AAA cells.

 

[TakeTheActive]

Re: Initial charge on Eneloops (AAA)

How can you tell which version you have?

Just out of curiosity, you understand, have you ever considered SEARCHing the CPF Archives and/or READing the (already assembled for you) FAQs?

:welcome: [Join Date: Mar 2007] 😕

CPF Post #97 (12-31-2005, 04:59 AM):

...How can I find out what version I have?
right after you plug in the charger, it displays the version number on the far right lcd cell...

[This thread is starting to remind me of the 'mV = Cell Capacity' thread... 🙁 I should log off and go to bed... :sleepy: ]

 

[Russel]

Re: Initial charge on Eneloops, charging strategies. (AAA)

[OPINION]

• If you've been using rechargeable cells for YEARS and already have a stockpile of (possibly / most likely) CRAP cells, buy the BC-900 first and then get the MH-C9000 when funds allow (and you can also buy new LSD cells).
  .
• If you're a "Rechargeable Cell Newbie", just starting out, with a stockpile of NEW 'vibrant' LSD cells, buy the MH-C9000 first and then get the BC-900 when funds allow (and your original new LSD cells are approaching CRAP).

[/OPINION]

That's interesting. I've got the BC-900 with a MH-C808 on the way and a MH-C9000 planned for the near future.

I wonder how many of us have both the BC-900 and the MH-C9000?

Anyway, would you use the BC-900 for charging the 'vibrant' LSD cells and the MH-C9000 for the older, delapitated cells? Or, maybe I should just ask you: How would you use the two chargers with a combination of new LSD cells and older, more questionable cells?

Russ

 

[TakeTheActive]

Re: Initial charge on Eneloops (AAA)

...The charger used is a MH-C9000. During normal charging it restricts max voltage to 1.47v before terminating cycle. During the manual (Break-in) mode, voltage is not terminated at 1.47v and the cells were charged to a fuller capacity...

Are you sure about this?

I'm an 'old' (12/06) BC-900 owner and 'new' (01/09) MH-C9000 owner. I ran a NEW / NEVER USED set of 4 Rayovac I-C3s through 'Break-In' on the C9000 and they finished just fine (which I was planning to communicate to SilverFox). I recently ran a USED set of 4 Rayovac I-C3s through 'Break-In' on the C9000 and they cancelled out and dropped into 'Charge' (for just a few mAh). I re-started them and watched the display (quite often) and they were at 1.47VDC just before the switch. I 'Discharged' them at 100mA (to break down any large crystals) and repeated the 'Break-In' and had the same problem - they dropped back out into 'Charge'.

I'm aware of the "Rayovac IC3 Cells Terminate Charge via Internal 'Pressure Switch'", and I can't see this being involved at 0.1C. I tried 'Break-In' three times on the C9000 before I switched over to the BC-900 (I have a 'Refresh 200/100' and 'Refresh 700/350' currently in progress; First 700/350 just finished at 1925mAh).

 

[Mr Happy]

Re: Initial charge on Eneloops (AAA)

I'm an 'old' (12/06) BC-900 owner and 'new' (01/09) MH-C9000 owner. I ran a NEW / NEVER USED set of 4 Rayovac I-C3s through 'Break-In' on the C9000 and they finished just fine (which I was planning to communicate to SilverFox). I recently ran a USED set of 4 Rayovac I-C3s through 'Break-In' on the C9000 and they cancelled out and dropped into 'Charge' (for just a few mAh). I re-started them and watched the display (quite often) and they were at 1.47VDC just before the switch. I 'Discharged' them at 100mA (to break down any large crystals) and repeated the 'Break-In' and had the same problem - they dropped back out into 'Charge'.

I think what you are finding is that I-C3 cells are not "normal" cells. They contain some internal magic that cuts off the charger when they think they are fully charged. On the C9000 this confuses it, since it will think the battery has been removed and reinserted. On reinsertion the C9000 will forget the break-in cycle and default to charge mode.

Short answer: do not use I-C3 cells other than on the Rayovac charger. They are specially designed and will not behave like normal NiMH cells in every case.

 

[NiOOH]

Re: Initial charge on Eneloops (AAA)

The cause of the -delta V signal is the rise in temperature of the cell. It is the way the chemistry works; the voltage decreases as the temperature increases. What happens is that when the cell is full and can no longer absorb much charge, the excess current gets converted to heat, and this heat raises the temperature and produces a small drop in voltage. The charger senses this drop and stops charging.

There is no need to use a fan for cooling unless you notice the cells getting uncomfortably hot at the end of charging. Slightly warm or even mildly hot is not a problem.

The direct cause of the voltage drop is the increase of the internal resistance of the cell, which in turn, is caused by the increase of temperature.
That is why, I usually do not recommend adding active cooling to chargers (fan). Although cells may be cooler at the end of charge, overcharge may occur.

 

[Mr Happy]

Re: Initial charge on Eneloops (AAA)

The direct cause of the voltage drop is the increase of the internal resistance of the cell, which in turn, is caused by the increase of temperature.

I think maybe you mean decrease of internal resistance on increasing temperature?

 

[TakeTheActive]

Re: Initial charge on Eneloops, charging strategies. (AAA)

That's interesting...

...I wonder how many of us have both the BC-900 and the MH-C9000?

Anyway, would you use the BC-900 for charging the 'vibrant' LSD cells and the MH-C9000 for the older, delapitated cells?

The REVERSE! 😱

With a stockpile of (possibly / most likely) CRAP cells, ~8-20+ years old, while I'm trying to run every one of them through a C9000 'Break-In', I'm getting a few 'HIGH' and 'MODE' errors (don't tell SilverFox - he'll just say RECYCLE!). My 'old' BC-900, on the other hand, will accept them (i.e. no NULL!).

...Or, maybe I should just ask you: How would you use the two chargers with a combination of new LSD cells and older, more questionable cells?

My 'NEW' C9000 has been running 'Break-Ins' on my existing inventory, 24x7, for 6+ weeks now. And just recently, I got the 'Bright Idea' :tinfoil: to also track Internal Resistance via the C9000's initial voltage reading. Cells that register 'HIGH' on the C9000 go to a 'Refresh 200/100' on the BC-900, hoping to break down the large crystals that formed from my neglect (read about 'Storage Box Queens' in my Sig Line LINK). Due to the different design of measuring discharge 'Under Load' (C9000) vs 'Off Load' (BC-900), the BC-900 can drain 'neglected' / high resistance cells lower (closer to 0.9VDC) than the C9000.

My 'NEW' LSDs (Eneloops, Duraloops, and Kodak) are still sitting SEALED in their packages, patiently awaiting their turn on the C9000, while the poor, aged, loyal, often-neglected Rayovac 1600s are slowly, but surely, hitting the RECYCLE bin... :candle: :mecry: 🙁

 

[NiOOH]

Re: Initial charge on Eneloops (AAA)

IMHO, you're hanging out in a BAD NEIGHBORHOOD. 😱 Move to 0.5 - 1.0C and you'll feel MUCH safer... :grouphug:

Buy yourself an inexpensive digital thermometer with a remote probe like the RadioShack one Russel shows in his photo. I have an older RS model and you'll be surprised how HOT 😡 a STILL safe 120ºF :wave: feels to the touch.

Actually, 120ºF (48.9 ºC) should not feel that hot to the touch. At work, I have an incubator that I frequently set to run at 50 ºC +/- 0.1 ºC (122 ºF). At that temperature I can touch and hold my hands on the internal metal surfaces without any problem. Then again, peoples sensitivity to heat may vary. IMO however, the temperature measured by these probe termometers is quite a bit lower than the actual cell skin temperature. This is manly due to the poor contact between the probe and the cells. Looking at the picture, you'll see that only half of the probe surface is in contact with the cells (and this trough the poorly heat-conducting plastic sleeve), the other half is cooled by ambient air. So, for me this is not a proper method to measure cell temperature. However, it could be used to measure dT/dt. Although absolute values will be lower the rate of temperature increase will be accurate. If you have a time to run such experiments (writing down time and temperature towards the end of quick charge say, every 20 seconds) it will be great.

 

[Muse]

Re: Initial charge on Eneloops (AAA)

Just out of curiosity, you understand, have you ever considered SEARCHing the CPF Archives and/or READing the (already assembled for you) FAQs?

:welcome: [Join Date: Mar 2007] 😕

CPF Post #97 (12-31-2005, 04:59 AM):
[This thread is starting to remind me of the 'mV = Cell Capacity' thread... 🙁 I should log off and go to bed... :sleepy: ]

Thanks for your relenting, and speaking your mind. Yeah, I joined a while ago but took a sabbatical. I haven't hung out here steadily. I'll try to be a better citizen. :wave:

 

[Turbo DV8]

Re: Initial charge on Eneloops (AAA)

Deleted due to erroneous information presented.

 

[Mr Happy]

Re: Initial charge on Eneloops (AAA)

Sorry if this has been mentioned, because I haven't read the next two pages of posts. "Test" on the LaCrosse will only dispay discharge capacity while discharging. As soon as it begins the next charge cycle, the discharge capacity is erased and "accumulated" capacity is displayed. So unless you are right there at the charger observing the discharge current as the voltage hits 0.9 volts, the displayed "capacity" of the cell at end of test is not the discharge current, but the accumulated capacity. The only mode on the LaCrosse which retains the discharge capacity in the display during the subsequent charge is refresh mode. Just wait for it to go to charge, note the discharge capacity, then if you don't want another refresh cycle, simply unplug and plug back in the wall wart and set your charge rate.

This does not sound logical, though. What use would the "Test" mode be if it did not test the capacity of the battery and display it to you on completion?

In Table 7 of the BC-900 user guide at the foot of page 5, it says that the mAh shown on the display after the 2nd charge has finished is "Capacity of the battery determined in discharging".

According to the user guide, both "Test" and "Refresh" mode show you the measured discharge capacity after the cycle ends.

Are you saying this is not what actually is displayed in reality?

Reference: BC-900 user guide

 

[Turbo DV8]

Re: Initial charge on Eneloops (AAA)

This does not sound logical, though...
Are you saying this is not what actually is displayed in reality?

Let me get home after work tonight and revisit my manual and charger. That is my recollection, but I will say that now owning two C-9000's has certainly turned more than one BC-900 feature on it's head, so I may be getting confused. I will check and edit post if I stand corrected. Thanks.

 

[Russel]

Re: Initial charge on Eneloops (AAA)

Sorry if this has been mentioned, because I haven't read the next two pages of posts. "Test" on the LaCrosse will only dispay discharge capacity while discharging. As soon as it begins the next charge cycle, the discharge capacity is erased and "accumulated" capacity is displayed. So unless you are right there at the charger observing the discharge current as the voltage hits 0.9 volts, the displayed "capacity" of the cell at end of test is not the discharge current, but the accumulated capacity. The only mode on the LaCrosse which retains the discharge capacity in the display during the subsequent charge is refresh mode. Just wait for it to go to charge, note the discharge capacity, then if you don't want another refresh cycle, simply unplug and plug back in the wall wart and set your charge rate.

That is interesting, because the BC-900 that I am using, when in test mode, will display the --- at first while it charges the cell and while discharging the cell after that. After the (top off) charge and discharge are complete it will display the capacity discharged while the cell is recharged in the third and final part of the test cycle.

I know that when the display shows capacity and test and charge, I have the tested capacity of the cell and the unit is now recharging the cell. The capacity remains the same number throughout the final charge. I have one right next to me that is displaying 1079mah for an old radioshack 1500mah cell in test mode charging after discharge. It has been like that with the same number for the last few hours.

Russ

 

[Russel]

Re: Initial charge on Eneloops, charging strategies. (AAA)

The old radioshack 1500mah cell just finished charging, completeing the test cycle. The BC-900 now displays:

Flashing back and forth between these two:

1079mah
charge
test

and

FULL