manual
21
victron energy
4. BATTERY CAPACITY
4.1 Calculation of the minimum required battery capacity
If the power ratings of the equipment to be powered by the Phoenix
inverter and the duration that the inverter is expected to power the
equipment are known, the minimum battery capacity can be calculated.
Make a list of all equipment to be powered by the Phoenix inverter and
sum up each single power consumption multiplied by the duration of time
in hours, during which power will be consumed (Watt-hours). Add the
internal loss of the Phoenix inverter.
The calculation on the internal loss is a two step process. First we
calculate the loss when the inverter is supplying power to a load. The
efficiency of the inverter in this state is 85%, adding roughly 15% to the
power consumption. When the inverter is not supplying power to a load,
power consumption is approximately 4W.
Determine the number of Ah by dividing the power consumption by the
nominal battery voltage (for example 24 V
DC
). The result is the total
battery capacity-consumption in Ah's. Multiply this value with a safety
factor of 1,7 and the result is the recommended minimum battery
capacity.
