Battery Voltage DOD Under Load

[Sfcjames]

Hi All, I am new to solar and the forum. I have a question about battery voltage and depth of discharge. How much does depth of discharge play a factor when the panels are producing power. For example, how does it affect batteries if I am holding steady at a float voltage and cloud cover causes my batteries to drop to 50% DOD for 5-6 minutes then recovers back to a float mode. Thank you.

[SunEagle]

Until you get a chance to measure your batteries while they are "resting" and have not been under charge or discharge for a while there is no accurate way to know what state they are in. Also measuring the voltage is not a good way on knowing the SOC of a FLA type battery. The best way would be to use a hydrometer to check the acid level concentration as well as knowing the temperature of the fluid. Any other measurement would be guess work and a crap-shoot in determining the battery condition.

[Mike90250]

Actually, if your batteries quickly drop to 50% when a cloud goes by, you are either consuming too much power for the batteries to safely supply, or the batteries are sulfated and worn out. What brand/model is the charger, and what sort of loads are you running off the batteries?