Remark on inverters types

Key differences (quick reference)

This technical remark summarizes the different types of inverters used in solar and backup energy systems. Inverters are divided into three families:

1-charger‑inverters

2-grid‑tied inverters

3-hybrid inverters

The aim is to help readers recognize the differences and interpretequipment labels correctly.

Charger‑inverters (inverter/charger)

Description: A charger‑inverter is an integrated device that converts DC power from batteries to AC and acts as a battery charger when grid or generator power is available. It combines an inverter and a battery charger in one unit. This makes it suitable for off‑grid or backup power systems where batteries are essential.

• Function: During normal operation, the inverter supplies AC power to loads using stored battery energy, and when AC input (grid or generator) is present, the AC output is supplied directly by this source (pass-through mode) while the battery is simultaneously recharged.

• Labeling: These devices are labelled CHARGER-INVERTER(Brand Model) XX VDC YYY VAC ZZ kVA,

  • XX: is the battery voltage (e.g., 48 V),
  • YYY: is the AC output voltage (e.g., 230 V)
  • ZZ:is the apparent power rating (kVA)

• Example:CHARGER INVERTER (Victron Quattro) 48 VDC 230 VAC 5 kVA

• Characteristics:

  • Battery reliance: connects to a battery bank, the DC voltage is usually 12/24/48 V.
  • Bidirectional power flow: charges the battery and supplies power.
  • No grid feed‑in: these devices cannot export power to the grid,they focus on providing AC from stored energy, this feature can be disabled or limited .
• Applications: off‑grid homes, recreational vehicles, UPS systems and backup power.
• Solar input : possible via external MPPT controller

Grid‑tied inverters

Description: A grid‑tie inverter converts DC power from solar panels to AC and synchronizes it with the utility grid. It uses the grid for voltage and frequency reference and exports excess energy to the grid to reduce electricity bills.

• Grid dependence: Because grid‑tie inverters rely on the grid, they shut down automatically during a grid failure for safety reasons.
• Labeling: These devices are labelled INVERTER PV (Brand Model) XX kVA AAA/BBB VDC where:
• XX is the output power (kVA)
• AAA/BBBindicatesthe minimum/maximum MPPT input voltage (e.g., 580/850 VDC for a Fronius Eco 25.0‑3‑5).

• Characteristics:

  • No batteries: grid‑tie inverters do not store energy, they only use solar energy during day light .
  • Feed‑in capability: surplus energy is fed back to the utility grid, reducing electricity bills.
  • They stop operating during power cuts.
  • High efficiency: conversion efficiency often reaches 95–98 %.

• Applications: Grid‑connected residential or commercial PV(photovoltaic)systems in regions with reliable power supply. They are cost‑effective and simple to install.

Hybrid inverters

• Description: A hybrid inverter combines the functions of a solar inverter and a battery inverter. It manages power from the PV array, battery storage, and the grid in one device allowing excess power to be sent back to the grid while also charging batteries.

• Flexible operation: Hybrid inverters balance energy from solar panels, batteries, and the grid and can draw power from the grid to charge batteries when solar production is insufficient.

• Labeling: These devices are labelledCHARGER‑INVERTER hybrid (Brand Model) XX kVA YY kWp, where:

  • XX:is the AC output power and
  • YY:is the maximum PV input capacity
  • Example: CHARGER‑INVERTER hybrid (SungrowSH25T) 25 kVA, 50 kWp

• Characteristics:

  • Battery support and grid interaction: hybrid inverters handle battery charging/discharging and can export power to the grid.
  • Backup power:they maintain power to connected loads using stored energy whenever the main grid is down.
  • Smart management: some models support remote monitoring and automatic switching between power sources
  • Higher cost and complexity:additional battery management leads to higher upfront cost and more complex installation