© Brooke Clarke 2007
When attempting to test the eneloop Ready
To Use Sanyo AA batteries the Maha - C777Plus
Charger/Analyzer could not properly test them. It's gone back
to the factory for repair. But even if it's working properly
the initial small charge makes the discharge capacity measurement
wrong. This is especially imnportant when testing shelf life
on the eneloop cells. The MH-C9000 is designed to only work
with single cells, not packs like the 777. Also there
are 4 test positions each of which can hold either a AA or AAA cell
and each test position is independent of the others. There is
a common LCD for all four test positions that can be pointed to any
of the four channels.
Although this is a charger analyzer for AA or AAA cells, but I don't
see why it could not also work with C or D cells, i.e. any single
cell rechargable battery that was Ni-Cad or Ni-MH.
Along with the C9000 a 4 pack of the Powerex 2.7 AH AA cells was
ordered. The first application for the C9000 is to discharge
all four cells to see how much charge is in them So far
there's no obivious date code on the blister pack or cells to give
an idea of how long it's been since they were charged. The
cells are made in Japan.
Sep 2016 update. Found a C/D cell adapter on eBay with the
title "C & D Battery Adapter Test C&D Cell in Power BM200
BT-C2000 BT-C3100 Charger"
Only two of them can be used because D cells are wider than AA
Trying it out on some old Radio Shack 4500 mAh cells. The
charge rate is 2000 mA max.
When a new cell is installed in one
of the channels the display asks for the Mode. The options
- Refresh & Analyze
- Discharge - Current is programmable 0.1 A to 1.0 A with a
fixed termination voltage of 1.0 V.
This is a pure discharge and nothing
else. With four cells installed the LCD cycles through each
of the four test positions and reports the number of minutes that
channel has been discharging, the current cell voltage and the mAh
the cell has delivered. When finished next to the
channel number is "DONE". The display cycles through each
channel and through minutes volts and mAh. It does NOT
charge after the discharge.
The results are:
The cells were essentially dead as received.
To go on to another mode each cell needs to be removed from the
C9000 and reinserted to start a new mode selection. This is
a very good thing, unlike the C777 that does an automatic charge.
Break-in (aka Forming)
This mode is recomended for new
cells and after 30 charges on existing cells. After
selecting Break-in mode and pressing ENTER the next screen asks
for the battery capacity, in this case 2700 mAh, once that's set
and ENTER pressed the Break-in starts (it's 8:40 pm 1 Nov).
Next there is a 16 hour charge at 0.1 C (270 ma ending at 12:40 pm
After a few hours the cell voltage
is at 1.4 and holding, but more and more mAh are going into the
cells. LCD shows Current Progress Charge
After about 700 minutes the cell voltage is 1.49, 2.845 mAh. -
Note it takes more than C to charge a battery. How much
more is a measure of efficiency.
A one hour rest time (ending at 1:40 pm 2 Nov).
1.46 to 1.47 Volts & 3910 to
Discharge at 0.2 C (should take 13.5 hours and end at 3:40 am on
1.14 V @ 2588 to 2607 mAh ended
more like 6:40 pm
A one hour rest time (ending at 4:40 am Nov 3).
A 16 hour charge at 0.1 C ( ending at 8:40 pm Nov 3).
3 Nov 2007 -811 minutes, charging
@269 ma, 1.49 V 3293 to 3308 to mAh
When finished around noon 3 Nov 2007:
Maha says that down to 2500 is
acceptable for the "2700" rated batteries and that's other makers
also use the same method of rating capacity.
Things That Could be Better
A way to change the defaults.
For example now I'd like to charge and discharge at 200 ma but
when a new battery is installed and charge selected the current
has a factory default of 1000 ma.
A way to keep alive the settings when the power fails, not so much
the utility fails but either the wall wart or the plug into the
C9000 gets disconnected. I can fix this with a simple add-on
Although the C9000 can not charge
NiZn batteries, it can discharge them.
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