10. Capacity Testing Battery
The battery capacity can be measured and verified by following the below test procedure. This should be
performed using calibrated test equipment and performed by a suitably qualified person.
To determine the battery capacity, the below process should be conducted by a suitably qualified
professional and performed at an ambient temperature of 25°C:
• Discharge the battery at 0.5C until the low voltage cut-off is reached, this will be determined by the BMS
going open circuit.
• Charge the battery at the recommended continuous charge voltage and 0.5C rate and hold at that
voltage for 6 hours.
• Discharge the battery with a constant load at 0.5C until the low voltage cut-off is reached. This will be
determined by the BMS going open circuit.
• Record the number of hours it takes to reach low voltage cut-off point.
• Charge the battery at the recommended continuous charge voltage and 0.5C rate for 6 hours.
The State of Health of the rated capacity can now be calculated as below and as a % of original capacity:
(((Ah*0.5)*Discharge hrs)/Ah)*100 =
Ah = Amp Hour Capacity.
0.5 = 0.5C constant load discharge.
100 = Conversion to %.
Example:
Eco4840P Ah Capacity = 78Ah
Battery time to discharge under test = 1.85hrs
= (((78*0.5)*1.85)/78)*100
= 92.5%
Eco P Series Installation Manual V3.0
21/10/2021
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