A solar inverter converts the direct current (DC) produced by solar panels, or stored in batteries, into alternating current (AC) that appliances, tools, and the utility grid can use. The right type depends on one question: where does your solar power need to go — to the grid, into batteries, or straight into a load?

⚫Connected to the grid, no battery: on-grid inverter or micro inverter
⚫No grid, with batteries: off-grid inverter charger
⚫Grid ➕ battery backup: hybrid solar inverter
⚫Solar power for a water pump, no battery: solar pump inverter

Inverter.com supplies all five types, from 120W micro inverters to 10kW hybrid inverters. This page explains how to choose between them, size a system with simple formulas, and what to check before you buy. Browse the full range in the Solar Inverter catalog.

 

Inverter.com Products for Use:

On-Grid Inverter	Off-Grid Inverter	Micro Solar Inverter	Solar Pump Inverter	Hybrid Solar Inverter

In this guide

• Which Solar Inverter Do You Need?
• Six Reference Configurations
• How to Match Solar Panels to an Inverter?
• How are Grid-tie Inverters Validated?
• Frequently Asked Questions about Solar Inverters

Which Solar Inverter Do You Need?

 

Inverter type	Battery needed?	Works during a grid outage?	Power range at inverter.com	Best for
On-grid(Grid-tie) inverter	No	No — shuts down when the grid is lost	300W – 50kW	Small grid-connected home systems
Off-grid inverter	Yes	Yes — it is the power source	700W – 200kW	Cabins, RVs, remote sites, backup power
Micro inverter	No	No — shuts down when the grid is lost	120W – 2800W	Rooftops, balconies, partially shaded arrays
Solar pump inverter	No	Not applicable	Sized to the pump motor	Irrigation, livestock water, remote wells
Hybrid solar inverter	Yes, for backup and storage	Yes, when batteries are installed	3kW – 10kW	Homes and small businesses that want solar, storage, and grid together

 

Quick rules of thumb

• If you have no grid connection, you need an off-grid inverter or a hybrid inverter with batteries.
• If you want the lights to stay on during an outage, a grid-tie or micro inverter alone is not enough, because it must stop feeding power when the grid goes down.
• If you only want to cut your electricity bill and don't worry about outages, a micro or grid-tie inverter is the simplest and lowest-cost route.
• If you are pumping water, a solar pump inverter drives the motor directly from the panels, and a storage tank replaces the battery.

Six Reference Configurations

The six examples below are illustrative sizing examples built from the formulas in this guide. They are not installation records. Confirm final values against the datasheet of the exact model and the rules where you live.

All examples use the same two assumptions: 4 peak sun hours per day (the full-sun equivalent of daily sunlight) and 75~80% overall system efficiency after wiring, temperature, and inverter losses. Your location will differ.

 

#	Scenario	Recommended Inverter	Solar array	Battery	Daily result
1	Balcony or small rooftop	ATO-SMI-SG400MS micro inverter	1 panel, 400W	None	≈ 1.28kWh of solar energy
2	Off-grid cabin	ATO-OGI-LS303 3kW inverter charger	≈ 2kW	≈ 7.5kWh (156Ah at 48V)	Supplies a 6kWh daily load
3	Grid-connected home, 230V	ATO-GTI-TL1500 1.5kW grid-tie inverter	8 × 200W = 1.6kW	None	≈ 5.1kWh of solar energy
4	Home backup	ATO-HSI-5.5kW48-230 5.5kW hybrid inverter	≈ 5kW	≈ 10.5kWh (219Ah at 48V)	≈ 16kWh of solar energy
5	Solar irrigation	Solar pump inverter + 5HP vertical centrifugal pump	4.8~5.5kW	None (water tank)	≈ 90~108 m³ of water
6	Workshop or small business	ATO-HSI-10kW48-230 10kW hybrid inverter	≈ 10kW	Optional, for peak shaving	≈ 32kWh of solar energy

🔴Configuration 1 — Balcony or small rooftop: one panel, one micro inverter

 

At a glance
Requirement	Add solar to a grid-connected home with space for a single panel
Recommended Inverter	400 Watt Solar Micro Inverter (ATO-SMI-SG400MS)
Solar array	One 400W panel
Battery	None
Daily result	1.28 kWh, about 470kWh per year
Check before buying	Compare the panel's open-circuit voltage and short-circuit current with the micro inverter's input limits. Being grid-tied, it stops producing during a grid outage.

 

Sizing: Daily energy = panel power × peak sun hours × system efficiency = 400 W × 4 h × 0.8 = 1.28 kWh per day.

Why a micro inverter: Each micro inverter tracks the maximum power point of its own panel, so shade or dirt on one panel does not drag down the others. The ATO-SMI-SG400MS is rated IP65 for outdoor mounting and cools by natural convection, so it has no fan to fail.

🔴Configuration 2 — Off-grid cabin with a 3kW inverter charger

 

At a glance
Requirement	A cabin with no grid connection using about 6 kWh per day (lighting, refrigerator, water pump, electronics)
Recommended Inverter	3 kW Split-Phase Off-Grid Inverter Charger, 24V/48V (ATO-OGI-LS303)
Solar array	About 2000W
Battery	About 7.5kWh, or 156Ah at 48V
Daily result	Covers the 6kWh daily load with one day of battery autonomy
Check before buying	Confirm whether the model has an integrated solar charge controller. If not, add an MPPT solar charge controller.

 

Sizing, step by step: 

1. Daily load: 6 kWh
2. Solar array: 6000 Wh ÷ (4 h × 0.75) = 2000 W of panels
3. Battery bank: 6 kWh × 1 day of autonomy ÷ 0.8 usable depth of discharge = 7.5 kWh, which is about 156 Ah at 48 V
4. Inverter size: The total of all loads running at the same moment must stay below 3,000 W. Motor loads such as pumps and compressors can draw several times their running power for a moment at start-up, so add that surge to the total.

Operating modes: The ATO-OGI-LS303 can be set to battery-first, AC-first, or energy-saving mode, which lets you choose whether the battery or an AC source (such as a generator) carries the load.

🔴 Configuration 3 — Grid-connected home on a 230V single-phase supply

 

At a glance
Requirement	A home on a 230V single-phase supply that wants to offset daytime consumption without batteries
Recommended Inverter	1500W Single-Phase Gri-Tie Solar Inverter (ATO-GTI-TL1500), 180~450V DC input, up to 1600W DC input power
Solar array	8 panels × 200 W = 1600W, wired in one series string
Battery	None
Daily result	About 5.1 kWh per day, or about 1870 kWh per year
Check before buying	Confirm the maximum DC input voltage on the datasheet, and confirm your utility's approval requirements before connecting to the grid

 

Sizing: Use example panels rated 200W, with Vmp (voltage at maximum power) of 36V and Voc (open-circuit voltage) of 44V.

• Panels in series, upper limit: 450V ÷ 48.6V (Voc corrected for cold weather, see the next section) = 9.3, so no more than 9 panels
• Panels in series, lower limit: 180V ÷ (36V × 0.85 for hot-weather voltage drop) = 5.9, so at least 6 panels
• Choose 8 panels (8 × 200W = 1600W), which matches the inverter's maximum DC input power
• Daily energy: 1.6 kW × 4 h × 0.8 = 5.1 kWh per day

🔴Configuration 4 — Home backup with a 5.5kW hybrid inverter

 

At a glance
Requirement	A grid-connected home that wants solar self-consumption plus power for essential loads (refrigerator, lights, router, well pump) during outages
Recommended Inverter	5.5kW Hybrid Solar Inverter (ATO-HSI-5.5kW48-230), 5500W rated, up to 6500W maximum power, DC input up to 500V
Solar array	About 5kW
Battery	About 10.5kWh, or 219Ah at 48V
Daily result	About 16kWh of solar energy, enough to recharge the battery and carry daytime loads
Check before buying	Keep the cold-weather open-circuit voltage of each string below the 500V input limit

 

Sizing: 

• Backup battery: 700W average essential load × 12 hours = 8.4kWh, ÷ 0.8 usable depth of discharge = 10.5kWh, which is about 219Ah at 48V
• Solar array: 5 kW × 4 h × 0.8 = 16 kWh per day

How it behaves: A hybrid inverter combines the functions of a PV inverter, a charge controller, and a battery inverter in one unit. With the grid available, it can feed solar power to the loads and the grid; during an outage, it runs essential loads from the battery and solar.

🔴Configuration 5 — Solar irrigation with a solar pump inverter

 

At a glance
Requirement	Pump 18 m³ per hour from a well against a total head of 30m, with no grid connection and no battery
Recommended Inverter	A solar pump inverter with a vertical centrifugal pump of about 5HP (3.7kW)
Solar array	4.8~5.5 kW (1.3~1.5 times the motor rating)
Battery	None; a water tank stores the output
Daily result	About 90~108 m³ of water with 5~6 hours of useful pumping
Check before buying	Choose the DC input range that fits the array (200~350V or 350~750V options), and keep the array's cold-weather Voc below the upper limit.

 

Sizing, step by step: 

1. Hydraulic power = flow (m³/h) × head (m) × 2725 = 18 × 30 × 2725 ≈ 1470W
2. Pump shaft power at an assumed 50% pump efficiency = 1470 ÷ 0.5 ≈ 2.9 kW, so a 3.7 kW (5 HP) motor leaves a comfortable margin
3. Solar array: commonly sized at 1.3~1.5 times the motor rating, which gives 4.8~5.5 kW of panels, because output falls in weak sunlight
4. Water output: 18 m³/h × 5~6 hours = 90~108 m³ per day, stored in a tank for use after sunset

Why no battery: The pump inverter's built-in MPPT control varies motor speed with sunlight, so the pump speeds up and slows down with the sun. A water tank stores the output more cheaply than batteries. Many solar pump inverters also accept single-phase or three-phase AC input as a backup source.

🔴 Configuration 6 — Workshop or small business with a 10kW hybrid inverter

 

At a glance
Requirement	A small shop on a single-phase supply with mostly daytime loads that wants to cut peak-time grid purchases
Recommended Inverter	10kW Hybrid Solar Inverter (ATO-HSI-10kW48-230), single phase, 300~900V DC input, MPPT range 350~850V or 400~800V
Solar array	About 10kW
Battery	Optional, to store midday surplus for evening peak-rate periods
Daily result	About 32 kWh of solar energy
Check before buying	Output is single-phase. Three-phase machines need separate equipment, such as a frequency inverter or a phase-conversion solution.

 

Sizing:

• Array: 10 kW of panels × 4 h × 0.8 = 32 kWh per day
• Peak shaving: The hybrid inverter can store midday surplus in batteries and release it during evening peak-rate periods ("peak-shaving and valley-filling")
• String design: Choose a string length so the working voltage stays inside the MPPT range in both hot and cold weather (see the next section)

How to Match Solar Panels to an Inverter?

Three checks decide whether a string of panels is compatible with an inverter. Do them in this order:

1️⃣Voltage check

Solar panel voltage rises in cold weather and falls in heat, so check both extremes.

◉ Maximum voltage (cold morning): The string's open-circuit voltage must stay below the inverter's maximum DC input voltage.

• Voc at cold temperature = Voc × [1 + temperature coefficient × (25 °C − lowest expected temperature)]
• Example: a 44V panel with a −0.30%/°C coefficient at −10 °C = 44 × (1 + 0.003 × 35) = 48.6 V per panel

◉ Minimum voltage (hot afternoon): The string's operating voltage (Vmp) must stay above the lower end of the MPPT range; otherwise, the inverter cannot track the maximum power point. Allow roughly a 15% voltage drop at high cell temperatures.

2️⃣Current check

The combined short-circuit current of strings connected in parallel must stay below the inverter's maximum DC input current. For example, the 3kW Hybrid Solar Inverter lists a maximum input current of 18A.

3️⃣Power check

Compare the array's rated power with the inverter's. An array rated at 1.0~1.3 times the inverter's AC rating is common, but never exceed the inverter's stated maximum DC input power.

 

Check	What you compare	Safe if
Voltage (cold)	String Voc × number of panels, corrected for cold	Below inverter maximum DC input voltage
Voltage (hot)	String Vmp × number of panels, reduced for heat	Above lower end of MPPT range
Current	Total Isc of parallel strings	Below inverter maximum input current
Power	Array rated power	Below inverter maximum DC input power

 

Use matching solar connectors and solar panels rated for the system voltage.

How are Grid-tie Inverters Validated?

Before a grid-tie inverter is approved for use, it is tested against a set of grid-connection standards. Understanding these tests explains why a grid-tie inverter behaves the way it does, including why it stops during an outage and restarts after the grid returns.

◎ Test equipment

A grid-connection test platform has two main instruments:

 

Instrument	What it does
Grid simulator	Simulates abnormal grid voltage and frequency, voltage dips until recovery, and the sudden loss of grid voltage. It tests whether anti-islanding protection acts within 2 seconds and isolates the inverter to protect it from damage. Rated from hundreds of VA up to several MVA.
I-V simulator	Simulates the current-voltage curve of a solar array, including shaded panels, and tests the inverter's MPPT efficiency. High-end units reach 2250V and several MW.

 

◎ Anti-islanding

If the grid fails while an inverter keeps energizing the local wires, a dangerous "island" forms that can endanger utility workers. Grid-tie inverters must therefore detect grid loss and stop feeding power quickly. This is why grid-tie and micro inverters shut down during outages unless they are part of a system designed for backup operation.

◎ Low (zero) voltage ride-through

Low voltage ride-through (LVRT) requires a grid-connected inverter to stay connected and keep supplying power for a short period while the grid voltage dips, until the grid returns to normal. A grid simulator can generate the required low-voltage waveforms from a few settings (voltage levels U1–U4 and time intervals t1–t5), and the result is checked on an oscilloscope.

◎ Grid distortion simulation

A real grid is never perfectly clean. Test systems add harmonics (2nd to 40th order) to the simulated grid voltage and create three-phase voltage or frequency fluctuations and unbalance to confirm that the inverter keeps operating correctly.

Frequently Asked Questions about Solar Inverters

• Q1: What is the difference between a grid-tie, an off-grid, and a hybrid solar inverter? 
  A grid-tie inverter feeds solar power into the grid and needs no battery. An off-grid inverter runs on its own from batteries and cannot synchronize with the grid. A hybrid inverter can work with both the grid and batteries, so it supports solar self-consumption and backup power in one unit.
• Q2: Will a grid-tie or micro inverter work during a power outage? 
  No. Grid-tie and micro inverters must stop feeding power when the grid fails, a safety rule called anti-islanding. To keep power during an outage, you need a hybrid inverter or an off-grid inverter with batteries.
• Q3: Do I need batteries with a solar inverter? 
  It depends on the type. Grid-tie and micro inverters work without batteries. Off-grid systems need batteries, and hybrid systems need them for backup and storage. Solar pump inverters need no battery because a water tank stores the output.
• Q4: How many solar panels can I connect to one inverter? 
  The limit is set by voltage, current, and power. Panels in series must keep the combined cold-weather open-circuit voltage below the inverter's maximum DC input voltage, and the operating voltage above the lower end of its MPPT range. Total array power must also stay within the inverter's maximum DC input power.
• Q5: Should I choose a micro inverter or a grid-tie string inverter? 
  A micro inverter is connected to a single panel, so shading or a fault on one panel does not reduce the output of the others. A grid-tie inverter serves a whole string of panels and is typically the simpler option for larger arrays with uniform sun exposure. Micro inverters suit small or shaded installations.
• Q6: What size solar inverter do I need? 
  Add up the loads that will run at the same time and choose an inverter with a continuous rating above that total, allowing extra for motor start-up surges. Then size the array at about 1.0~1.3 times the inverter rating without exceeding its maximum DC input power.
• Q7: Can a solar pump inverter run a pump without batteries? 
  Yes. A solar pump inverter drives the AC pump motor directly from the panels using built-in MPPT control. The pump speeds up and slows down with the sunlight, and the water is stored in a tank for use when the sun is down.