Trickle Voltage: A Crucial Indicator.

Maintenance voltage measurements at the cell or monoblock level are measured to ensure proper charging. Any cell with a significant deviation of the holding voltage from the string average may indicate defects but will not provide any indication of battery capacity or remaining life.

Current and Temperature: Preventing Safety Risks.

Measuring the holding current, ambient temperature, and battery temperature can help prevent a possible thermal runaway in order to avoid a subsequent system safety risk. The holding current may increase if one of the elements short-circuits, or it will drop due to sulfation of the cells as the batteries age as they approach the end of their life cycle, but it is not a sensitive indicator for the state of charge of the battery but will indicate information for the health of the battery.

Download Complete: The Most Reliable Method of Diagnosis

The test fordefining theexact capacity that the battery is still capable of maintaining is through full discharge of the battery and that determines the battery's performance relative to the data provided by the manufacturer, usually in terms of capacity measured in Ah. To do this requires external load banks, the work is difficult and the battery being tested must be disconnected from the load. In these situations, the system is unable to back up any grid disconnections resulting in inconvenience to the effectiveness of the system. The type of discharge test that follows this method with a depth of discharge > 90% (DoD) provides a reliable measurement of battery performance. Usually this type of test is suitable for laboratories and not for being performed in the field.

Partial Discharge and Advanced Solutions

An alternative to the full discharge test is to perform a partial discharge using the system load. This technique usually involves disconnecting the primary power supply to the loads, shifting the entire system load onto the battery. Battery performance is generally evaluated 'while performing the discharge' because the depth of discharge is often too different to allow comparison with the manufacturer's published performance data. Partial discharge can estimate residual capacity by extrapolation if the release voltage is provided by the manufacturer while not providing absolute accuracy. The best solution is to keep the battery disconnected from the load at all times, and to be able to control it in charging and discharging through a microcontroller that stores its current and voltage in Charge and Discharge and is able to determine its accumulated capacity through continuously self-learning algorithms.