Neptune R450 MC, Installation And Maintenance Manual

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Appendix C
R450 Mini Collector Installation and Maintenance Guide 77
You can measure the batteries both voltage open circuit (Voc) and
voltage under charge (Vuc). The Vuc is a simple method to measure
voltage without disabling the load or disabling the system from
charging. Use Voc when the battery end of life is in question, and a more
accurate means of measurement is required.
Batteries should be tested for end-of-life whenever a particular system
begins to fall in a state-of-charge (SoC) below 80% repeatedly, or the
system begins to exhibit LVD on a recurring basis. This may vary
depending on load use, depth of discharge and temperature extremes,
but can vary between 3
–
10 years.
To measure for battery end-of-life:
1 Disconnect the battery from the system.
2 Charge the battery with an appropriate three-stage battery charger.
3 After completion, allow the battery to settle for three hours with no
charge or load attached.
The following table provides Voc and Vuc for SoC at 25°C.
Table 19 Battery Load Voltage by DOD
DOD (%) 120 hr. Rate (volts)
10 12.69
20 12.58
30 12.45
40 12.32
50 12.18
60 12.05
70 11.88
80 11.65
90 11.40
100 10.50
These voltages are averages and will vary slightly from battery to battery
even of the same rating. However, they are a good indicator of state of
charge for Concorde AGM batteries. This data is for newer batteries with
relatively few cycles. An older battery will measure a lower voltage for a
given DOD.