Sears 200.7121 owner manual Calculating charge time, Charge RATE/CHARGING Time Hours, AMP 10AMP

Calculating charge time

The Chart Method

Use the following table to more accurately determine the time it will take to bring a battery to full charge. 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 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 RECOMMENED.

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 69-percent charge prior to recharging. Add more time for severely discharged batteries.

	BA'I-rERYSIZE/RATING			CHARGE RATE/CHARGING TIME - HOURS
				2 AMP	10AMP
SMALL	Motorcycle, garden	6	-12 AH	2-4	NR
BATTERIES	tractor, etc.	12	-32 AH	4-10	NR
	200 - 315 CCA	40	- 60 RC	11-14	2 - 27/8
CARFRUCKS	315 - 550 CCA	6O	- 85 RC	14 -18	27/8-33/4
	550 - 1000 CCA	85	-190 RC	18 - 35	33/4- 7
MARINE/DEEP	CYCLE	80 RC		18	31/2
		140 RC		27	51/2
		160 RC		30	6
		180 RC		33	7

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 PERCENTPERCENTOF

GRAVITY OF CHARGE CHARGE NEEDED

i

1.265100%0%

1.22575%25%

1.15525%75%

1.1200%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 by2, 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 10 amps).

Multiply the result by 1.25 and you'llhave 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 Settingof charge

100 (AH Ratinq) x .50 (cherqe needed) x 1.25 = 6.25

10 (Charger Setting) hours

100x.50=5x1.25=6.25

10

You would need to charge your lO0-Ampere Hour Bat- tery for approximately 61/4hours at the lO-Amp charge rate using the above example.