The size of your inverter limits how much solar energy can be used in your home at any given time.
Ever wondered why you are drawing energy from the grid when you have ample solar energy to cover your household load? It’s likely that your household load is exceeding the capacity of your inverter. This won’t happen often, as your system has been sized to cover most of your energy needs. But occasionally, when you have the A/C working hard and other appliances in use, your household load, or energy use, may exceed the amount of energy your inverter can push to your home.
Here's the maths:
A 5 kVA inverter (Plico’s most popular inverter size, also called a 5 kW inverter) is able to output around 5 kW to your home at any given time. If your energy use exceeds 5 kW, you will draw the excess energy required from the grid, no matter how much solar you are producing and how much capacity you have in your battery. Most household energy use can be met within the limit of 5 kW, however larger or 3-phase energy homes may require a larger inverter.
This rule also applies for energy drawn from your battery and the combination of both solar energy and battery energy – all output to your home is limited by the size of your inverter. Redback 5 kVA inverters are limited to 5 kW, however, can only output 4.6 kW for battery alone. AlphaESS 5 kVA inverters can output 5 kW.
The inverter limit applies only to the energy being sent to your home. Your panels can produce far more than this at any given time and the excess can be sent to your battery or the grid without impacting the amount your home receives.
Your inverter converts the direct current (DC) generated by your solar panels into alternating current (AC), which is what most of your home appliances run on. Its capacity determines how much electricity it can convert (from your solar panels and your battery) and send to your home at any given time.
If you are drawing from the grid when your household load is less than your inverter’s capacity, it could be due to other reasons. Read this article to find out more.