Amp hours = reserve capacity + 16 2 – Sears 28.71234 User Manual
Page 17

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15
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BATTERY SIZE/RATING
ChARGE RATE/
ChARGING TIME - hOURS
2 AMP 20 AMP 60 AMP
SMALL
BATTERIES
Motorcycle, gar-
den, tractor, etc.
6 - 12 AH
2 - 4
NR
NR
12 - 32 AH
4 - 10
NR
NR
CAR/TRUCKS
200 - 315 CCA
40 - 60 RC
11 - 14
60 - 90
min.
20 - 30
min.
315 - 550 CCA
60 - 85 RC
14 - 18 90 - 120
min.
30 - 40
min.
550 - 1000 CCA
85 - 190 RC
18 - 35
2 - 3.5
hrs.
45 - 60
min.
MARINE/DEEP CYCLE
80 RC
18
105 min.
NR
140 RC
27
2 hrs.,
45 min.
NR
160 RC
30
3 hrs.
NR
180 RC
33
3.5 hrs.
NR
The hydrometer or Electronic Method
14.2
To find the time needed to fully charge your battery, determine the bat-
tery’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 GRAvITY
PERCENT OF ChARGE PERCENT OF ChARGE
NEEdEd
1.265
100%
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 approximate time needed to bring your
battery to a full charge.
To
convert Reserve Capacity to Amp Hours, divide Reserve Capacity by
2, and add 16:
Amp Hours = Reserve Capacity + 16
2
NOTE: The Reserve Capacity can be obtained from the battery specifica-
tion sheet or the owner’s manual.
To calculate time needed for a charge:
Find the percent of
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charge needed. (A battery at 50 percent charge that