Mh-C9000: R&A vs. Cycle

[TakeTheActive]

C9000 Impedance Check Voltage on *CRAP* Cells...

Well, it looks like Cell #3 and #4 have problems... ...I Discharged the 4 last night @ default rates; 2 of the 4 banks showed 0 mah upon completion. I'd never seen this before so set them on Charge at default rates this morning. The same 2 banks showed up HIGH. Strange considering the results above, less than a month ago. I let the 2 batteries rest, then tried charging them in the maha-c204w. Same result, red flashing light...won't charge...

Welcome to the 'Rechargeable Cells w/High Internal Resistance' Club!

What is the C9000 Impedance Check Voltage on these *crap* cells?

...Strange considering the results above, less than a month ago. I let the 2 batteries rest, then tried charging them in the maha-c204w. Same result, red flashing light...won't charge...

...I wanted to attempt a revival of some powerex 2700s [dated 07-08], that have been more or less storage box queens. I've done a couple of break-ins giving results ranging from 2100-2350...

...I have so many cells that I don't get to use most of them. So they end up spending more cycles "refreshing" than actually powering something. I still have cells that have only been cycled since bought years ago but never gone in a device, sigh...

You guys crack me up...

Who would buy cells and wear them out testing rather than using them in devices...

Several weeks ago, 45/70 posted a method that he used to use, IIRC, to attempt to dissolve crystals. It's tedious and time consuming (Discharge @ 100mA to 0.9VDC; Charge @ 0.5C for ~5min; REPEAT), but, it sounded viable so I tried it:

Rayovac I-C3 2000mAh AA      [B] |   #5    #6    #7    #8
---------------------------------+---------------------------

09/xx/09 C9000 Break-In: 1600    |  n/a     x   n/a     x mAh

09/xx/09 Sears Solar LED Lamp    |  n/a   ---   n/a   --- mAh
09/xx/09 BC900 Discharge:  100   |  n/a     x   n/a     x mAh
09/20/09 C9000 Discharge:  400   |  n/a  1549   n/a  1638 mAh

09/20/09 C9000 Break-In: 1800    |  n/a  HIGH   n/a  OPEN mAh
09/19/09 C9000 Discharge:  100   |  n/a    15   n/a     0 mAh
09/19/09 C9000 Discharge:  400   |  n/a  1617   n/a  1676 mAh
09/20/09 C9000 Break-In: 2000    | 1639  HIGH  1655  MODE mAh
09/18/09 C9000 Discharge:  100   |    0   125     4    10 mAh
09/18/09 C9000 Discharge:  400   | 1556  1470  1498   960 mAh
09/11/09 SAKAR Charge:  150      |  n/a   ~24   n/a   ~24tHrs
09/10/09 C9000 Impedance Check:  |  n/a  1.62   n/a  1.64 VDC
09/10/09 Sears Solar LED Lamp    |  n/a   ---   n/a   --- mAh

08/23/09 BC900 Discharge:  100   |  n/a   ---   n/a   --- mAh
08/23/09 C9000 Discharge:  100   |  n/a   ---   n/a   --- mAh
08/23/09 C9000 Discharge:  400   |  n/a  1529   n/a  1706 mAh
08/23/09 C9000 Break-In          |  n/a  HIGH   n/a   n/a mAh#

08/21/09 BC900 Discharge:  100   |  n/a   ---   n/a   --- mAh 
08/21/09 C9000 Discharge: 1000   |  n/a  1396   n/a  1649 mAh
08/21/09 BC900 Charge: 1800      |  n/a +1781t  n/a   --- mAh

08/20/09 C9000 Break-In          | 1687   n/a  1698   n/a mAh#
08/19/09 C9000 Discharge: 1000   | 1664   n/a  1617   n/a mAh

08/18/09 C9000 Discharge:  100   |  n/a    74   n/a    38 mAh
08/18/09 C9000 Discharge:  400   |  n/a  1575   n/a  1663 mAh
08/18/09 C9000 Break-In          | 1729  HIGH  1781     3 mAh#

08/16/09 C9000 Impedance Check:  | 1.59  1.68  1.59  1.66 VDC
08/16/09 Superman 1AA Flashlight |   ~3    ~2    ~3    ~1 Min
08/16/09 BC900 Discharge:  100   |   21    28     8    77 mAh
08/16/09 C9000 Discharge:  100   |   77    54    91    28 mAh
08/16/09 C9000 Charge: 2000:3m   |  101   101   102   100 mAh

08/16/09 C9000 Impedance Check:  | 1.60  1.71  1.59  1.66 VDC
08/16/09 Superman 1AA Flashlight |   ~1    ~2    ~1    ~4 Min
08/16/09 BC900 Discharge:  100   |   22    26     8    41 mAh
08/16/09 C9000 Discharge:  100   |   35     9    47     2 mAh
08/16/09 C9000 Charge: 2000:2m   |   52    53    53    52 mAh

08/16/09 C9000 Impedance Check:  | 1.60  1.69  1.59  1.64 VDC
08/16/09 Superman 1AA Flashlight |   ~2   ~10    ~1    ~2 Min
08/16/09 BC900 Discharge:  100   |   23    28     8    46 mAh 
08/16/09 C9000 Discharge:  100   |   47    19    66     9 mAh
08/16/09 C9000 Charge: 2000:2m   |   53    54    54    53 mAh

08/15/09 C9000 Impedance Check:  | 1.60  1.67  1.59  1.59 VDC
08/15/09 Superman 1AA Flashlight |   ~2   ~30    ~7    ~6 Min
08/15/09 BC900 Discharge:  100   |   22     7    11    41 mAh
08/15/09 C9000 Discharge:  100   |   30     2    52     2 mAh
08/15/09 C9000 Charge: 2000:2m   |   53    56    56    54 mAh

08/15/09 C9000 Impedance Check:  | 1.60  1.70  1.60  1.79 VDC
08/15/09 BC900 Discharge:  100   |   33   RST    16   RST mAh
08/15/09 C9000 Discharge:  100   |  152   125   193    99 mAh
08/15/09 C9000 Charge: 2000:5m   |  200   201   203   201 mAh

08/13/09 Superman 1AA Flashlight |    2    15     2     2 Min
08/13/09 C9000 Impedance Check:  | 1.60  1.69  1.60  1.80 VDC
08/13/09 BC900 Discharge:  100   |   19    79    37   106 mAh
08/13/09 C9000 Discharge:  100   |   80    13    96    25 mAh
08/13/09 C9000 Charge: 1000:6m   |  100   100   100   100 mAh

08/13/09 C9000 Impedance Check:  | 1.60  1.68  1.60  1.80 VDC
08/13/09 BC900 Discharge:  100   |   18    93    27    99 mAh
08/13/09 C9000 Discharge:  100   |   54    25    98    16 mAh
08/13/09 C9000 Charge: 1000:6m   |  100   101   100   100 mAh

08/12/09 C9000 Impedance Check:  | 1.62  1.70  1.61  1.80 VDC
08/12/09 BC900 Discharge:  100   |   10   116    37   102 mAh
08/12/09 C9000 Discharge:  100   |   35    20    82     7 mAh
08/12/09 C9000 Charge: 1000:6m   |   90   101   110   100 mAh
08/12/09 BC900 Discharge:  100   |    0   118    41   100 mAh
08/12/09 C9000 Discharge:  100   |    0   167    19     0 mAh
[Bought: mm/dd/yy - HP Camera, GPS, RS Thermometer]
 --- Results not recorded
 n/a Cell not included
 RST BC-900 reset itself when programming new channel
 't' Cell's internal (pressure) switch TRIPPED

Note the eventual drop of C9000 Impedance Check Voltage on Cell #8. Also take note of how much more the BC-900 DISCHARGE @ 100mA (500mA @ 20% Duty Cycle) can get out of the cell compared to the C9000 DISCHARGE @ 100mA (1000mA @ 10% Duty Cycle). Then, look at how long the '*FREE* Duracell Superman 1AA Incandescent Flashlight' DISCHARGE runs (until the bulb is COMPLETELY extinguished, AFAICT) after the BC-900 is done.

I interpret the drops in BC-900 and Superman Flashlight numbers as the dissolving of the large crystals and thus the reduction of the cell's Internal Resistance, resulting in an increase in the cell's Capacity @ 0.2C.

Granted, the average (sensible) rechargeable cell user would just RECYCLE *crap* cells and move on (the ROI vs Time-Invested ratio STINKS! ). But, for those of us with the TIME, and the CURIOSITY, IMHO experiments like these increase our knowledge.