Originally Posted by trosenthal20
The solar controller is an Outback FlexMax80. The battery monitor is a Xantrex LinkPro. The inverter is a Xantrex fsw3000.
Batteries are Deka AGM rated at 198A@20hrs and 1110cca.
Keep in mind that your solar controller does *not* have a wire dedicated to "sense" battery voltage, hence it will measure battery voltage through the same wire used to pump current from controller to battery. This means that the controller will overestimate battery voltage by the voltage drop. between controller and batteries. This is particularly troublesome when the installer puts the controller close to the panels to make his/her life easier.
In addition, the default setting for this controller is an absorption time of yet again one hour (see "Advanced-Absorb Time Limits") . This means the thing will go down to float voltage before the batteries are full, particularly if the voltage at the battery, which determines current acceptance is lower than the charger thinks because of voltage drop in the wires.
Bottom line is: The batteries are not full until they only accept less than 10 amps (say 1% of 5x198Ah, which is a reasonable parameter for AGMs) when held at the manufacturerīs recommended absorption voltage, which for AGMS is in the order of 14.4 plus/minus temperature comp.
I do not know if you have the technical manual for Deka, which is a useful read: http://www.dekabatteries.com/assets/base/0139.pdf
See p11 where it says that charging
voltage at 70-80°F (whcih is roughly the base for temp compensation in your controller) should be 14.3V. Elsewhere it says "Set charger at .. .. 14.4 to 14.6 volts at 68°F for AGM.
Therefore you way want to confirm that your "absorption voltage" setting in the Outback is not less than 14.4V. You could add a couple tenths ( no more) to compensate for voltage drop if necessary.
I hope I have explained how important it is to make those batteries hit 144V and stay there for a while every day.
Regarding how long that "while" should be, you can test for 100% charge by disconnecting one battery for 24 hours and measuring "rested" Open Circuit Voltage that should be at least 12.8 volts (see p.13). If you had Lifeline AGMs you could just look for current to drop to 5 or 10 amps while held at 14.4 volts, but that spec is not provided by Deka.
Sorry for following that tangent, but if your batteries are not well looked after your fridge will not work well, period.