When a solar project is too small for the MAX Series but still demands genuine off-grid performance, the SP Series Off Grid Solar Inverter steps in. Designed for residential homes, small cabins, rural shops, and light-commercial standalone systems, the SP Series delivers the same core off-grid functions — MPPT charging, pure sine wave output, and battery management — in a compact, cost-effective chassis.

This guide explains what the SP Series is best at, who should choose it over the MAX Series, and how to size it correctly.

1. What Is the SP Series?

The SP Series is a family of low-to-mid power off grid solar inverters typically rated from 1kW to 5kW. It integrates three functions into one unit:

1. MPPT solar charge controller — harvests maximum energy from the PV array

2. DC-AC inverter — converts battery DC to clean AC for home or office loads

3. Automatic transfer switch — switches between battery/inverter and grid or generator input when available

It is ideal for systems where space, budget, and installation simplicity matter more than the heavy-duty ratings of the MAX Series.

2. Key Features

Built-In MPPT Solar ChargerThe SP Series uses a high-frequency MPPT algorithm that tracks the solar panel's optimal operating point in real time. Compared to a basic PWM controller, MPPT can deliver up to 30% more charging current, especially on cold, sunny days when panels produce higher voltage.

Pure Sine Wave OutputEven in a compact enclosure, the SP Series outputs true pure sine wave AC (THD < 3%). This means sensitive electronics — LED TVs, Wi-Fi routers, refrigerator compressors, and laptop chargers — run quietly and reliably without the buzzing or overheating caused by modified sine wave inverters.

Flexible Battery CompatibilityThe inverter works with lead-acid flooded batteries, AGM and gel batteries, and LiFePO₄ lithium battery packs. Charging parameters (bulk, float, equalization voltages) are configurable through the LCD panel or software.

UPS Backup FunctionWhen a utility grid or generator input is connected, the SP Series charges the battery from AC while supplying loads normally. If AC input fails, it transfers to battery power in under 10 milliseconds — fast enough to keep computers, routers, and small medical devices running without interruption.

Compact Wall-Mount DesignThe SP Series is light enough to wall-mount, saving floor space in utility rooms, small plant rooms, and kiosks. Its fanless or low-speed fan design keeps operation quiet.

3. SP Series vs. MAX Series: Which One Do You Need?

• Choose SP Series if: your total connected load is under 5kW, you have a small battery bank, and the installation is a home, office, or small rural business.

• Choose MAX Series if: you need to power motor-heavy loads (pumps, large compressors), multiple buildings, or a telecom site with 24/7 uptime requirements.

4. Typical Applications

• Rural and Remote Homes — lighting, refrigeration, fans, and entertainment

• Holiday Cabins and Eco-Lodges — quiet, maintenance-free power in a small utility closet

• Small Shops and Workshops — full off-grid supply or backup against frequent outages

• Telecom and CCTV Backup — small cellular repeaters, surveillance systems, remote weather stations

5. Sizing the SP Series System

1. List all loads — note wattage and daily usage hours.

2. Choose inverter size — pick the SP model whose continuous VA rating ≥ 1.25× your total running load.

3. Size the battery — for 1–2 days of autonomy: battery capacity (Ah) = daily Wh ÷ system voltage ÷ depth of discharge (0.5–0.7).

4. Size the solar array — array wattage ≈ daily Wh ÷ 4–5 peak sun hours × derating factor (0.8).

6. Get a Quote

Looking for a compact off grid solar inverter for a home, cabin, or small business? The SP Series offers reliable, cost-effective standalone solar power. Contact our engineering team for datasheets, model selection, and pricing tailored to your load profile.