FOSSiBOT SP400 Pro Bifacial Solar Panel

A 400 W folding TOPCon solar panel that collects light on both faces. It reaches up to 25 % efficiency, is rated IP67, and has a built-in 35° kickstand so you just unfold and stand it.

~~$499.29~~

4%$479.29

Price with code · Geekbuying · as of 2026-10-09

Code 26BTS01 · 6% off

max $20 · orders over $50 · until 2026-10-31

Copy code & shop Geekbuying

~~$499.29~~4%$479.29Copy code & shop Geekbuying

110–15 % more from the back

The rear face catches light reflected off the ground, adding 10–15 % in real use. On highly reflective surfaces such as mirrors the store quotes up to 24.85 %.

2Folds to carry

It weighs 9 kg and folds to 691 × 790 mm, with a rigid aluminium frame and thick corner guards. It works from -10 to 70 °C.

3MC4 standard, XT60 cable included

Standard MC4 connectors and an included MC4-to-XT60 cable fit most mainstream power stations. Two panels in series reach up to 800 W.

Key specs

Peak power: 400 W
Cells & efficiency: TOPCon monocrystalline · up to 25 %
Open-circuit voltage: 39.1 V
Water resistance: IP67
Weight: 9 kg
Size: Open 2765 × 790 mm · folded 691 × 790 mm

Good pick if

You want to charge a power station by sun
You spend long stretches off-grid or in an RV

Think twice if

You want something light for a backpack

FAQ

Is there a promo code?

Yes. Enter 26BTS01 at Geekbuying checkout when buying the FOSSiBOT SP400 Pro Bifacial Solar Panel for 6% off. Conditions: max $20 · orders over $50 · until 2026-10-31.

Will it fit my power station?

MC4 and XT60 cover most mainstream stations. Its open-circuit voltage is 39.1 V, so check that it falls within your station’s solar input range.

What’s in the box?

The panel, an MC4-to-XT60 solar charging cable, a carry bag and a manual.