Another battery Queestion

Re: Another battery Queestion

Peter,

It is the formation of Hydrogen and Oxygen gas on the plates while charging that "stirs" the electrolyte--Not just any heavy current flow (discharging in your case with the loads does not generate gas at the plate/electrolyte boundaries).

A good starting Rule of Thumb for Flooded Cell Lead Acid Batteries. Note Battery Amp*Hour Capacity is spec'ed here at the 20 Hour Rate:

• C/20 (5%) minimum rate of charge--planned long term discharge rate (efficient)
• C/10 (10%) about the optimum maximum rate of charging (recommended for tall "L16" type batteries) and discharging.
• C/8 (12.5-13%) Generally the maximum continuous charge/discharge rate for flooded cell batteries. Run risk of overheating batteries with higher rates of continuous current flow.
• C/2.5 (40%) maximum short term recommended surge current (starting loads for pumps, minimum battery bank capacity for Hybrid Inverter systems). Current in excess of C/2.5 for flooded cell may take the battery bank outside of 10.5-15.5 volt range (12 volt bank reference).

The above is my recommendations on posts I have read over the last few years here (and other Mfg. recommendations).

For your 900 AH battery bank (assuming 20 Hour Specification):

• 900 AH * 1/20 = 45 Amps minimum recommended charging current / optimum long term discharge current
• 900 AH * 1/10 = 90 Amps Optimum maximum current
• 900 AH * 1/8 = 112.5 Amps maximum continuous current
• 900 AH * 1/2.5 = 360 Amps maximum short term current (well pump starting surge, etc.)

Feel free to discuss offer other suggestions. Just one guy's opinion.

-Bill