Sears 200.7123 - Manual (Page 11)

Calculating charge times
The Chart Method
Use the following table to more accurately determine
the time it will take to bring a battery to full charge.
First, identify where your battery fits into the chart.
• Small batteries — motorcycies, garden tractors, etc.
— are usually rated in Ampere Hours (AH). For
example: 6 to 12 AH, or 12 to 32 AH,
• Batteries in cars and smaller trucks are usually rated
in Reserve Capacity (RC), Cold-Cranking Amps
(CCA), or both.
• Marine, or deep-cycle batteries are usually rated in
Reserve Capacity (RC).
* NR means that the charger setting is NOT RECOM­
MENDED.
Find your battery’s rating on the chart below and note
the charge time given for each charger setting. The
times given are for batteries with a 50-percent
charge. Add more time for totally discharged batter­
ies.
BATTEBV SKE/RATING
CHARGE RATE/CHAF tGING TIME-HOURS
SMALL
BATTERIES
Motorcycle, garden
tractor, etc.
6-12 AH 2-4 NR
12-32 AH 4-10 NR
САПЯПиСКЗ
200-315 CCA 40 - 60 RC 11 -14
315-550 CCA 60 - 85 RC 14-18 % - 1
550- 1000 CCA 85 -190 RC 18-35 1 - 2
MARINE/DEEP CYCLE
80 RC 18 NR
140 RC 27 NR
160 RC 30 NR
180 RC 33 NR
The Hydrometer or Electronic Method
To find the time needed to fully charge your battery,
determine the battery’s charge level with a hydrometer
or electronic Percent-of-Charge Tester. The following
table will help you convert hydrometer readings to
percent of charge values.
SPECIFIC PERCENT PERCENT OF
GRAVITY OF CHARGE CHARGE NEEDED
1.265 1 0 0 % 0 %
1.225 75% 25%
1.155 25% 75%
1.120 0 % 100 %
When you know the percent of charge and the Amp
Hour (AH) rating of your battery, you can calculate the
time needed to bring your battery to a full charge.
To convert Reserve Capacity to Amp Hours, divide
Resenre Capacity by 2, and add 16:
Amp Hours = Reserve Capacity + 16
2
To calculate time needed for a charge:
• Find the percent of charge needed. (A battery at 50
percent charge that will be charged to 100 percent
needs another 50 percent (.50).
• Multiply the Amp Hour rating by the charge needed
(.50) and divide byjhe charger setting (2 or 10
amps).
• Multiply the result by 1.25 and you'll have the time
needed, in hours, to bring the battery to full charge.
• Add one additional hour for a deep-cycle battery.
Example:
Amp HourBfltingx%Qlcharqeneededx 1.25 = hours
Charger Setbng of
charge
100 fAH Ratlnol X .50 (charge neededi x 1.25 = 6.25
40 (Charger Setting) hours
100 X . 50 = 1.25 X 1.25 = 1.5625
40
You would need to charge your 100-Ampere Hour
Battery for approximately
1 hours at the 40-Amp
charge rate using the above example.
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