I'm sure there are thousands of posts regarding this, and no end to advice either! However I'm currently residing in the camp of those who aren't exactly sure whether the batteries are getting to 100% or not.
I've recently purchased several SLA batteries so a specific gravity reading is not possible. The only clue is the voltage and current readings I'm getting.
Battrery pack is 24volts and 400AH.
Typical winter daily profile is 23.2 volts at sunrise under a 10Amp load, followed by a gradual reduction in load and an increase in current from the panels that takes it up to a net charging current of 23Amps at midday. The voltage at the batteries usually peaks at about 29.4 volts around 14:00 to 15:00 in the afternoon. By the evening they are on "float charge" at 27.3 volts. Evening peak current draw is no more than 25 Amps for a few hours followed by a reduction to about 8 amps until dawn. After the PV's stop producing the voltage falls steadily from 26 volts to 23.2 volts by dawn. Between 100 to 150AH are withdrawn overnight depending on how much TV we watch. Anything up to 150AH could be produced by the PV's depending on the weather this time of year. Battery voltages in the morning are always somewhere between 23.2 and 23.8 volts.
Is this normal? I've heard before that letting the batteries go below 2v per cell (24v) is very bad for lead acid and will lead to premature failure!
Any help would be much appreciated!
D
I've recently purchased several SLA batteries so a specific gravity reading is not possible. The only clue is the voltage and current readings I'm getting.
Battrery pack is 24volts and 400AH.
Typical winter daily profile is 23.2 volts at sunrise under a 10Amp load, followed by a gradual reduction in load and an increase in current from the panels that takes it up to a net charging current of 23Amps at midday. The voltage at the batteries usually peaks at about 29.4 volts around 14:00 to 15:00 in the afternoon. By the evening they are on "float charge" at 27.3 volts. Evening peak current draw is no more than 25 Amps for a few hours followed by a reduction to about 8 amps until dawn. After the PV's stop producing the voltage falls steadily from 26 volts to 23.2 volts by dawn. Between 100 to 150AH are withdrawn overnight depending on how much TV we watch. Anything up to 150AH could be produced by the PV's depending on the weather this time of year. Battery voltages in the morning are always somewhere between 23.2 and 23.8 volts.
Is this normal? I've heard before that letting the batteries go below 2v per cell (24v) is very bad for lead acid and will lead to premature failure!
Any help would be much appreciated!
D
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