Measuring Voltage; Open Circuit Voltage Characteristics After End Of Charge; Relation Between State Of Charge And Open Circuit Voltage - Suzuki SV650/S Service Manual

5
Sealed VRLA
Batteries

Measuring Voltage

How healthy is your sealed VRLA battery? Since a sealed
VRLA battery is sealed – and the sealing caps are never
removed – you won't be able to check the state of the
charge by the old hydrometer-and-specific-gravity test.
Rather, use a voltmeter or multimeter to measure DC volt-
age. It should be of class 1 accuracy or better.
basics to keep in mind:
Check voltage using a voltmeter. Readings for a
G
charged, newly-activated battery should be 12.8v
or higher after the battery is charged and sits for
at least 1 - 2 hours. If less, it needs an
additional charge.
The graph top right shows open circuit characteristics
G
of the sealed VRLA battery after end of charging
using a constant current charger set to the standard
current of the specific battery. As shown, the open
circuit voltage is stabilizing 30 minutes after end
of charge.
Therefore, to determine the state of charge and the
health of the battery, measure the open circuit
voltage 1 hour after end of charge.
For a battery that has been in use, refer to the graph
G
bottom right to determine state of charge from
open circuit voltage.
POINTS TO REMEMBER
❐
Use a voltmeter to determine state of charge. Because sealing caps are
never removed, you can't test specific gravity.
❐
Don't use a quick charge for initial activation.
❐
A battery that has just been activated or charged needs to stabilize
1 hour for an accurate voltage reading.
Open Circuit Voltage Characteristics
after End of Charge
Charge
18
17
Some
16
15
14
13
12
11
10
0
Relation between State of Charge
and Open Circuit Voltage
14
13
12
11
10
100
27
Ambient Temperature
Open Circuit 77°F (25°C)
10 20 35 40
Elapsed Time (minutes)
Ambient Temperature
32-104°F (0~40°C)
75 50 25
State of Charge (%)
50 60
0