Calculating Charge Time - DieHard 200.71315 Owner's Manual

Calculating charge time
The Chart Method
Use the following chart to estimate charge time when
charging in the MANUAL Mode. First, identity where
your battery fits into the chart.
• Small batteries -- motorcycles, garden tractors, etc.
-- are usually rated in Ampere Hours (AH). For
example; 6 to 12, or 12 to 32 AH etc.
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
RECOMMENED.
Find your battery's rating on the chart to the right and
note the charge time given for each charger setting.
The times given are for batteries with a 50-percent
charge prior to recharging. Add more time for severely
discharged batteries.
SMALL
BATI'ERIES
CAR/TRUCKS
Motorcycle, garden
tractor, etc.
200 - 315 CCA
315 - 550 CCA
550 - 1000 CCA
MARINE/DEEP CYCLE
6-12AH
12 -32 AH
40 - 60 RC
60 - 85 RC
85 -190 RC
80 RC
140 RC
180 RC
180 RC
2-4
4-10
11 -14
14-18
18-35
18
27
3O
33
NR
NR
11/2- 2
2 - 21/2
21/2- 41/2
21/2
31/2
4
41/2
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 below will help you convert hydrometer readings to
percent of charge values.
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
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 by the charger setting
(2 or 15 amps).
• Multiply the result by 1.25 and you'll have the
approximate time needed, in hours, to bring the
battery to full charge.
Add one additional hour for a deep-cycle battery.
Example:
Amp Hour Rating x charge needed x 1.25 = hours
Charger Setting of
charge
100 (AH Ratinq) x .50 (charqe needed) x 1.25 = 4.163
15 (Charger Setting) hours
1_.5 = 3.33 x 1.25 = 4.163
15
You would need to charge your 100-Ampere Hour Battery
for a little more than 4 hours at the 15-amp charge rate
in this example.