NSN 6130-99-391-3441 ()
Battery Charger Analyser : Operator Manual
6.2
Lead Acid Constant Current Charge
6.2.1
Parameters Required
a) Battery Nominal Voltage.
This is the normal nominal voltage of the battery to be charged.
b) Battery charge current.
This is constant current required to charge the battery.
c) Battery overcharge voltage.
This is the overcharge voltage of the battery.
6.2.2
Charge Operation
At the start of charge the charger will monitor the open circuit voltage of the battery
before starting. It will use this value to calculate the approximate duration of the
constant current charge.
This is based on the following algorithm: -
DURATION = -(OCV-((NOMINAL * 0.075)))*(199.2 / NOMINAL)
Where:
DURATION:
LENGTH OF CHARGE IN HOURS
OCV:
BATTERY OPEN CIRCUIT VOLTAGE
NOMINAL:BATTERY NOMINAL VOLTAGE
This algorithm has been derived from the specifics of MINISTRY OF DEFENCE -
AIRCRAFT BATTERIES GENERAL AND TECHNICAL INFORMATION AP113c-0001-1 3rd
edition.
The following table illustrates the source of data that was used to derive the
algorithm.
Typical charge rates are:
Battery Capacity
Constant Current Charge Rate
40AH
3.0A
25AH
2.0A
18AH
1.4A
Typical Charge Times would be:
Battery OCV
Approximate
Capacity
Charge Time Hours
25.8V
100%
0H
25.5V
80%
3H
25.2V
65%
5.5H
24.8V
50%
8H
24.6V
40%
9.5H
Doc: DWG1030-25-R11 Operators manual.odt
Page 16 of 72
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Printed On : 12/06/17