Santé ups c3ks is an online long-lasting power supply, the c3ks is just a mainframe. Nominal output power of 3K VA, 8 12V battery power supply. After the utility power interruption conversion by the allocated battery power supply, this time can be maintained for a period of time that can be calculated.
To the better ups conversion efficiency in the case of about 80% of the calculation, 3K VA output, the input side of the power input required: 3000 ÷ 80% = 3750 (VA). At 96 volts battery voltage, the current required from the input is 3750 ÷ 96 ≈ 39 (A), with 38ah battery, 38 ÷ 39 ≈ 0.97 (hours). That is about 1 hour. With the use of a long time, the battery capacity gradually decline, the sustainable power supply time becomes shorter. As you can see, using the battery capacity of 38ah as a base, each doubling of the base capacity will increase the sustainable power supply time by one hour. If you want to extend the total time to 4 hours, you need to match eight 150ah capacity battery. Batteries become larger, the battery cabinet increases accordingly, but also another with the same capacity of high-power charger. Even greatly exceed the price of the ups host.
On the other hand, the length of the sustainable power supply time, but also with the load, to use 38ah battery as an example, the load is reduced by half, then the sustainable power supply time is about doubled, that is, about 2 hours.