Selector

12 Volt

6 Volt

Switch

Battery

Battery

12V

1

2

24V

2

4

36V

3

6

48V

4

8

60V

5

10

72V

6

12

L.AMPSELECTORSWITCH

The charge rate of either 5 or 10 Amp maybe selected for any selected output voltage.

M.CHARGEPERIODANDTIMERSETTING

The approximate time required to bring a battery to a fully charged state depends upon the number of Ampere Hours (AH) depleted from the battery. AH’s are determined by multiplying the number of hours times the number of Amps supplied by a battery to a load.

For example: If a load was connected to a battery which drew 10 Amps for a period of 4 hours, the battery will have supplied 40 AH. The approximate recharge time would then be calculated by dividing the 40 AH depleted from the battery, by the ampere charge rate of the battery charger. Add an extra 20% for tapering of the charge rate and battery recharge inefficiency.

The required charge period for the above conditions would be approximately 5 hours. That Is, 10 Amps (depleted) x 4 (discharge period in hours) - 10 Amp (charger output rate) x 1.20 = 4.8 hours which = 4 hours and 48 minutes.

Another method to determine the required charge period is by means of performing a hydrometer test. Measure the specific gravity of the electrolyte, corrected for 80° F (26.7° C), of each cell.

Two common types of hydrometers are:

Types calibrated in terms of specific gravity (a common scale being 1.120 to 1.265) or the type which use four colored balls to Indicate state of charge. There are many types available. Read and follow the instructions that are provided with each type.

Specific Gravity Value

State of Charge

Floating Balls

1.265

100%

4

1.225

75%

3

1.190

50%

2

1.155

25%

1

1.120

Discharged

*

*No balls float in the barrel of the hydrometer.

If you have a 70H rated battery, and its hydrometer reading indicates a 25% state of charge, then 52.5 AH are needed to bring the battery back to 100% of charge.

(70AH - (.25 x 70)) = 52.5 AH

Charge period would be calculated as follows.

52.5AH -1-10 (amp rate) x 1.20 (120%) = 6.3 hours or 6 hours and 18 minutes. The timer would be set to 6.5 hours for this example.

If the charge rate switch is set to 5 Amps the charge time will be twice as long.

Indications of a fully charged battery are:

When the ammeter indicates the charge rate has tapered to approximately one half the charger rated output.

A hydrometer reading of the specific gravity of the electrolyte (fluid) of the battery in good condition should be between 1.250 and 1.285.

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Schumacher SE-1072 important safety instructions Ampselectorswitch, Chargeperiodandtimersetting