SUBJECT:<<<<<<<<-WHAT YOU SHOULD KNOW ABOUT NICAD BATTERY PACKS->>>>>>>>



CAPACITY:  EXPRESSED IN TERMS OF AMPERE HOURS (AH) OR MILLIAMPERE
           HOURS (MHA).  THIS IS A MEASURE OF THE DISCHARGE RATE
           NEEDED FOR THE BATTERY TO DROP ONE VOLT PER CELL WITHIN ONE
           HOUR. FOR EXAMPLE A FULLY CHARGED 4 AH BATTERY USED WITH A
           HT NEEDING 2 AH CURRENT WILL DISCHARGE IN APPROXIMATELY 2
           HOURS.  WHEN A BATTERY PACK'S CAPACITY DROPS TO 80% OF ITS
           RATED CAPACITY, IT SHOULD BE REPLACED.

VOLTAGE:   WHEN IN USE, THE VOLTAGE OF THE NICAD BATTERY PACK IS ABOUT
           1.2 VOLTS PER CELL.  THIS VOLTAGE REMAINS UNTIL THE CELL
           APPROACHES DISCHARGE.  IN NORMAL OPERATION, THE VOLTAGE
           SHOULD NOT DROP BELOW 1.1 OR 1.O PER CELL. NOTE: IF THE
           BATTERY PACK IS USED TO PROVIDE CURRENT ABOVE THE RATED
           VALUE THERE WILL BE A SEVERE DROP IN VOLTAGE WHEN DISCHARGE
           IS APPROCHED.  THIS REDUCES THE CAPACITY AND CAN RENDER THE
           BATTERY PACK USELESS.

CYCLES:    USED TO MEASURE THE LIFE OF A BATTERY PACK, A CYCLE IS A
           FULL CHARGE AND SUBSEQUENT DISCHARGE.  NICAD BATTERY PACKS
           SHOULD LAST 1000 OR MORE CYCLES (TWO TO THREE YEARS OF USE
           ASSUMING EIGHT HOURS DAYS, FIVE DAYS A WEEK) UNDER NORMAL
           CONDITIONS.

POLARITY
REVERSAL:  THIS OCCURS WHEN ONE OF THE CELLS REACHES ZERO VOLTAGE
           BEFORE THE OTHERS.  BECAUSE ALL CELLS ARE CONNECTED IN
           SERIES, A REVERSAL IN POLARITY OCCURS.  ALTHOUGH THIS
           SITUATION CAN BE REVERSED, IT SHOULD BE AVOIDED SINCE, IF
           DONE REPEATEDLY, IT WILL SHORTEN THE LIFE OF THE BATTERY
           PACK.

MEMORY
EFFECT:    ALTHOUGH MORE COMMON IN THE POWER PLATE BATTERIES OF
           YESTERYEAR, THIS CAN STILL OCCUR IF THE PROPER CARE ISN'T
           GIVEN.  WHEN A REPEATED SHALLOW DISCHARGE OF THE SAME
           AMOUNT OCCURS MORE THEN 200 TIMES, A BATTERY CAN SHOW A
           MEMORY EFFECT.  THIS RARELY OCCURS WITH NORMAL USE.  EVEN
           IF IT WERE TO OCCUR, THE BATTERY WILL SEEM TO HAVE A
           REDUCED CAPACITY OF ONLY ABOUT 10% WHICH IS NOT NOTICEABLE.
           THIS MEANS YOU'LL STILL HAVE ACCESS TO 90% OF ITS ORGINAL
           CAPACITY.

                         >>>>>>>>FACTS<<<<<<<

1.  BE SURE TO USE THE CHARGER THAT WAS DESIGNED FOR THE TYPE AND
    CAPACITY OF THE BATTERY PACK TO BE CHARGED.  CONTINUOUS
    OVERCHARGING MAY SHORTEN BATTERY LIFE.
2.  ALWAYS USE A CHARGER THAT SWITCHES TO A TRICKLE CHARGE AFTER THE
    BATTERY REACHES 60 TO 80% OF FULL CHARGE.  THIS AVOIDS BATTERY
    DAMAGE CAUSED BY CHARGING A BATTERY AT GREATER THAN A 10 HOUR RATE
    FOR LONG PERIODS OF TIME.
3.  UNDERCHARGING A BATTERY CAUSES THE MOST DAMAGE.  THE CAUSES FOR
    THIS  ARE USUALLY ONE OF TWO.
                    1. MISMANAGEMENT
                    2. DEFECTIVE CHARGER
4.  DO NOT FAST CHARGE BATTERIES THAT HAVE BEEN STORED FOR MORE THEN
    6-MONTHS.  START THEM OFF ON A SLOW CHARGE OVER A 14 TO 20 HOUR
    PERIOD.  AFTER THE FIRST CHARGE (SLOW CHARGE) A FAST CHARGE CAN BE
    USED FOR SUBSEQUENT CHARGES.
5.  NEVER FAST CHARGE BATTERIES BELOW 40 DEG F.  CHEMICALS REACT
    SLOWER BELOW THIS TEMPERATURE.  THIS MEANS A BATTERY PACK CAN'T
    ACCEPT HIGH CURRENT.  IF A HIGH CURRENT WERE USED TO CHARGE THE
    BATTERY UNDER THESE CONDITIONS, PRESSURE WILL BUILD UP IN THE
    CELLS AND THERE WILL BE A LOSS OF CAPACITY.
6.  CHECK NEW BATTERY PACKS AS THEY ARRIVE TO BE SURE THE CAPACITY IS
    STILL AT THE LEVEL NEEDED FOR YOUR EQUIPMENT.
7.  CHECK THE CAPACITY OF NICAD BATTERY PACKS EVERY THREE MONTHS WHEN
    USED EVERY DAY. CHECK EVERY SIX MONTHS WHEN USED LESS OFTEN.  IF
    THE BATTERY IS LESS THEN 80% OF ITS RATED CAPACITY, THEN THE
    BATTERY IS NEAR THE END OF ITS LIFE AND SHOULD BE DISPOSED.
8.  AVOID DEEP DISCHARGES.  IF A BATTERY SHOULD BE DISCHARGED BELOW
    ONE VOLT PER CELL, POLARITY REVERSAL MAY OCCUR AND THE BATTERY
    WOULD BE RENDERED USELESS.
9.  AVOID SHORT CIRCUIT BATTERY PACK, THIS CAN BE DONE CARRYING THEM
    IN YOUR POCKET WITH COINS OR KEYS.  IF A PACK SHORT CIRCUITS
    YOU'LL PROBABLY BURN YOUR FINGERS OR SOMETHING ELSE, ALL
    ACCORDING TO WHICH POCKET IT IS IN.
10. RESIST THE TEMPTATION TO BUY EXTRA BATTERY PACKS ON SALE, THEN LET
    HEM SET IDLE FOR LONG PERIODS OF TIME.  BATTERY PACKS THAT HAVE
    SIT IDLE FOR A LONG PERIOD OF TIME MAY TAKE AS MANY AS TEN CYCLES
    TO BRING THE BATTERY PACK BACK TO CAPACITY.
11. WHEN STORING BATTERIES BE SURE TO STORE THEM IN A COOL PLACE.
    STORING BATTERIES IN HIGH TEMP. CAUSES THE BATTERY TO SELF
    DISCHARGE, SPEEDING NATURAL DETERIORATION AND REDUCING CAPACITY.