Why does Victron Energy state inverter capacity in VA instead of W?

Learn the difference between VA and Watts, why it's important for your installation, and how it affects the sizing of your electrical system.

When you look at the specifications for Victron products like Multiplus, Quattro, or their pure inverter models, you'll notice that the capacity is stated in VA (Volt-Ampere) and not in Watts (W). This is due to how electrical power works.

The difference between VA and W

• VA (Volt-Ampere) is the apparent power – the total power that the inverter can deliver.
• W (Watt) is the active power – the part that actually does the work, such as powering a motor or heating an element.

The difference is due to the power factor (PF), which indicates how much of the apparent power becomes active power.

The formula is simple: Watts = Volt-Ampere × Power Factor.
Conversely: Volt-Ampere = Watts ÷ Power Factor.

Examples with Victron products

• Multiplus 12/3000/120-50 has a capacity of 3000 VA.
  At PF = 1, it delivers 3000 W.
  At PF = 0.8, it delivers 2400 W.
• Quattro 48/5000/70-100 has a capacity of 5000 VA.
  At PF = 0.85, it delivers 4250 W.

Why is this important?

Victron states VA to show the total capacity, as different loads have different power factors. Motors, pumps, and electronics draw reactive power, which means the actual power in Watts will be lower than the VA value.

How to calculate it yourself

• From VA to W: multiply VA by the power factor.
  Example: 5000 VA × 0.8 = 4000 W.
• From W to VA: divide Watts by the power factor.
  Example: 4000 W ÷ 0.8 = 5000 VA.

Common power factors

• Heating elements: 1.0
• LED lighting: 0.9
• Motors/pumps: 0.7–0.85
• Switched-mode power supplies: 0.6–0.9

Brief summary

Victron states capacity in VA because it is a neutral measure that works for all types of loads. To know how many Watts you can actually use, consider the power factor.