What does pure sine wave mean on a power station?

By the Ferncharge team · Figures last checked 21 October 2026

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The short answer: it describes the shape of the mains (AC) power a power station's inverter makes. Anker says pure sine wave power "is designed to closely resemble the electricity you get from a wall outlet" (Anker SOLIX). The alternative, modified sine wave, is a rougher, stepped version. It matters most for medical devices, motors, and audio and video equipment.

Based on manufacturers' published specs and guidance. Ferncharge has not tested these products.

Pure vs modified sine wave

A power station stores energy as DC in its battery. Its inverter turns that into AC for the mains sockets.

• Pure sine wave: a smooth output, close to what a wall socket supplies.
• Modified sine wave: a stepped approximation. Anker says it can make motors run hotter, louder or less efficiently, and is more likely to cause buzzing or flicker in audio and video equipment (Anker SOLIX).

When it matters

• Medical devices: Anker says many medical devices, "including some CPAP machines and oxygen concentrators, may require pure sine wave power" (Anker SOLIX). Check with your equipment supplier. See our CPAP guide.
• Motors: fridges, freezers and fans. See our freezer guide.
• Audio and video: TVs, speakers and similar equipment. See our TV and games console guide.

For phones, laptops and other devices that charge from USB or 12 V, the waveform doesn't apply: those outputs are DC and don't go through the inverter.

How to check a power station

Look for "pure sine wave" or the inverter type in the spec sheet or manual. Of the four models in our spec table, only one stated it in what we read:

Alphabetical. "Not stated" means we didn't find it in those documents, not that the output isn't pure sine wave. Ask the maker if you need to know before buying, especially for medical equipment.

FAQs

What is a pure sine wave power station?

One whose inverter produces smooth AC power, close to a wall socket's. BLUETTI states "Inverter Type: Pure Sine Wave" for the AC180.

Do I need pure sine wave?

For medical devices such as some CPAP machines, Anker says it may be required. It also matters for motors and audio and video equipment. Check your device's manual.

Does pure sine wave matter for charging a phone?

Not if you use a USB port: USB outputs are DC and don't use the inverter.

Related: CPAP machine · What is surge power? · Spec table