Before a problem is suspected with the system, read this section. There are numerous events that may appear as problems but are in fact perfectly normal. Please visit https://gpelectric.com/support/ for the most up-to-date FAQs and troubleshooting videos.

It seems like my flooded batteries are losing water over time.

Flooded batteries may need to have distilled water added periodically to replace fluid loss during charging. Excessive water loss during a short period of time indicates the possibility of overcharging or aging batteries.

When charging, my flooded batteries are emitting gas.

During charging, hydrogen gas is generated within the battery. The gas bubbles stir the battery acid allowing it to receive a fuller state of charge.

Important: Ensure batteries are in a well-ventilated space.

My voltmeter shows a different reading than the SOLAR CONTROLLER display.

The meter value on the SOLAR CONTROLLER display is an approximate reading intended for indication purposes only. There is an approximate 0.1 VDC inherent error present that may be accentuated when compared with readings from another voltmeter.

There may be a slight difference between the battery voltage displayed on the SOLAR CONTROLLER display and the battery voltage measured at the battery terminals. When troubleshooting using a voltmeter, check both the battery voltage at the SOLAR CONTROLLER controller terminals and battery voltage at the battery terminals. If a difference of more than 0.5 VDC is noted, this indicates a large voltage drop possibly caused by loose connections, long wire runs, small wire gauge, faulty wiring, a faulty voltmeter or all the above. Consult the Suggested Minimum Wire Gauge chart in Section 6 for wiring suggestions and check all connections.

For advanced users:

The SOLAR CONTROLLER makes voltage measurement adjustments based on resistance it detects at the battery terminals. In addition to resistance in the wires, batteries also have an internal resistance due to chemical properties. The controller cannot distinguish between these two sources of resistance. It will compensate up to 250mV in the displayed value.

Why does the voltage fluctuate so much when charging with the LITHIUM setting?

Lithium batteries contain smaller battery cells. The voltages of these individual cells must be balanced during the charging process by the Battery Management System (BMS). Imbalances will cause fluctuations in the battery voltage measurement, but this will stabilize as the cells are charged and balanced.

Additionally, lithium batteries have higher resistance than lead acid batteries. This affects the charge controller’s battery voltage measurements and its compensation for wire resistance.

Reduce wire inductance which may also cause voltage fluctuations. Keep battery wires close together, or gently twist positive and negative wires together.