DN1• 16
CONGRATULATIONS
You have just completed your DN1 NiCad battery conditioner unit. Take a
well deserved break now. Give your eyes a rest. When you return, be sure to
check over your work on the entire circuit board. Energizing the circuit board
with solder “bridges” or misplaced components can damage your kit. Don’t
throw away all your scrap component leads just yet, however, you’ll still need
a couple to set up your kit for its final operation.
DOCTOR NiCad BATTERY CONDITIONER SETUP
Its time to configure your Doctor NiCad for your individual application. We’ll
discuss a little theory first to more clearly understand the proper settings.
•NiCad batteries have a capacity rating, or “C” value, associated with
them. This value is usually defined in an Ampere-Hour rating. Typically,
the larger the battery cell, the larger the Amp·Hr rating.
•The quality of the NiCad is proportional to the charging rate of the
battery. That's why you have seen the exact same “looking” batteries (i.
e. same size, shape, and weight) while one is called a “fast charge” cell
and may cost twice as much! Many portable motor driven devices like
portable drills have higher capacity batteries for longer life. The higher
the quality of the cell the faster one can charge it, as high as a rate of 4
times the capacity (4C) of the cell. Be aware, however. that trying to
fast charge a cell not intended for this type of charge can cause the
cell to build up internal gasses too quickly and explode, regardless
of the complexity of the charger. If you cannot determine the proper
charging rate for your cell, the rate of C/2 is recommended.
•Once the charging rate is determined, you can easily calculate the safety
“time” out required for worry-free operation. This time is roughly 1½
times the charge capacity of the cells. This “time out” feature ensures
that your batteries will not be charged for too long.
Here’s an example of how to determine the correct setup:
We have a battery pack consisting of 4 “AA” type cells. The pack is marked
as having 500mA hr cells with a quick charge rate of 1 Amp.
With a charging rate of 1 Amp, the cell is storing charge at a rate of twice the
capacity, or (2·C), The battery in an ideal situation will acquire a full charge in
one-half hours time, or mathematically speaking, 1 A · .5Hr = .5A-Hr or
500mA-Hr. Notice in the Safety Time Out Jumpering Chart (page 17) that for
a charge rate of 2C the time out will be 45 minutes.