I've heard this term float charging voltage" mentioned here but I really do not know what it means
anyway it says float charging voltage for the 12volt units is 13.75 +or- 1.5 VDC
Float charge is holding the battery voltage at it's charged voltage... i.e. it's replacing whatever power is lost to self discharge.
I didn't see the UPS12-475FR listed in the pdf you provided but it listed 13.
65 +/- 1.5vdc as a float voltage for the MR series from Dynasty so 12.15 to 15.15 would be the range?
Another pdf I found listed the float voltage for the FR series as 13.3vdc minimum.
That same pdf (
www.cdtechno.com/custserv/pdf/7135.pdf also listed an equalization charge of 2.4v/cell or 14.4vdc (28.8 vdc in your case) and state this (also found at:
http://www.longwaybattery.com/en/displaynews001.html?newsID=159083):
"BATTERY PREPARATION FOR ACCEPTANCE TESTING
The battery system should be assembled at the manufacturer's site, simulating the user's installation, or completely installed at the user's location following relevant installation instructions.
1. Measure and record all cells1 units open circuit voltage to assure minimum acceptable voltage prior to interconnecting.
2. The individual cells1 units should be interconnected using the intercell/unit cables or bus bars specified for the application and with which the battery's performance is rated.
It is important that all cell1 unit terminals and contact surfaces of the intercell/unit connecting cables and bus bars be properly cleaned and greased prior to installation and the bolted connections be properly torqued. Improper connections can result in low measured capacity due to voltage drop at the connections.
3. Equalize the battery for 24 hours at the recommended voltage (e.g., 2.4 volts/cell) to assure the battery is fully charged.
4. Following equalization, the battery should be place on float charge at the recommended voltage (e.g., 2.30 volts/cell) for 3 to 7 days prior to the acceptance test.
5. Just prior to initiating the acceptance capacity test, measure and record the individual cell/unit float voltages. "
Battery University has lots of good info.
...but I said to an observer of my system that it had to do with bringing the individual batteries to the same voltage, so that electricity was not moving from less charged batteries from the batteries with a good charge, as they were before I rewired my system so that each battery has precisely the same length of cable run.
That description is good enough although it has more to do with individual cells.
From Battery University:
"Equalizing Charge:
With time, the charge levels of individual cells of a large battery tend to become slightly unbalanced. The equalizing charge applies an elevated charge voltage for a few hours to balance the cells. Used mainly for large lead acid cells."