Battery Settings

JRM

Now that my solar system is turned on, I need to set parameters for battery charging.  I thought this would be easy but ended up confused.  People on this forum must have years of experience with settings for battery banks, but my search efforts (here and elsewhere) did not find many recent questions or answers.

 I contacted the battery manufacturer and was sent the following settings for my 4- battery (48-volt) open lead-acid system:  absorption voltage = 62,4, float voltage = 54.0, and equalization voltage = 64.0.  These voltages seemed high compared to what I have read, and I could hear the batteries bubbling on the absorption setting.  Then I got to wondering why there should be so much difference between batteries by different manufacturers when the chemistry is the same.

I ended up using the following generic voltage recommendations for deep cycle lead-acid batteries:  absorption = 58.8V for 2 hrs., float = 52.8V, and equalize = 62.0V for 2 hrs. (I need to equalize manually and plan to do this about once a month.)  These numbers seem low, but I can still hear the batteries bubbling at the end of absorption.  The batteries seem to reach full charge on even partly sunny days, and I don’t want to shorten their lives by overcharging. Do the voltages I am using seem about right?  Is this something I should be concerned about?  And what are reasons for worrying about these settings?

JRMunn

Ralph Day

I would go with the manufacturer's settings.  Your generic ones were what I started with and trimmed years off the first set of batterie's lifetime.  Be prepared for logging sg and water usage numbers for warranty purposes.