FOSSiBOT SP420 420W Foldable Portable Solar Panel

10th of 46 we've scored in Portable Solar Panels

10th of 46 in Portable Panels

FOSSiBOT SP420 420W Foldable Portable Solar Panel

400 W or more panel
1-year warranty

SVT Score, Upper

Usability5.1/10Social5.7/10The SVT Score is placed on its category's range

Versus

SVT SCORESRead review

A 420 W four-section ETFE folding panel with four kickstands, an IP67 sunlit side and a cord pocket, weighing 30.79 lb, for FOSSiBOT and other MC4 power stations.

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SKU: USSP420 Category: Portable Solar Panels Brand: FOSSiBOT

Usability

5.1 out of 10

Capacity10420 W rated, on the 400 W and up rung for portable panels

Electrical: 32 V and 13.1 A at maximum power, 38.4 V open circuit and 15.7 A short circuit
Build: four 105 W sections of 182 mm monocrystalline cells, per a retailer copy of the spec sheet

Efficiency1018.2 percent computed from 2231 x 1036 mm, on the 18 percent and up rung

Marketed: cell efficiency of up to 23.4 percent, against the computed module figure

Lifespan1No power-output warranty on the product page or in the warranty policy

Better on lifespanRenogy 400W Solar SuitcaseRenogy's December 2025 warranty schedule gives 5 years to 95 percent. $495.99Scores 5.0

Features6IP67 sunlit side, ETFE front and four kickstands; no adapter cable listed, no diode count

Weather: FOSSiBOT calls the rating splash resistance and says not to leave the panel in rain

Verification2no directory record for the SP420; the store lists FCC, CE and RoHS only.

Searched: Intertek UL CEC LabTest TÜV SÜD Certipedia

Better on verificationAnker SOLIX PS400 Bifacial$699.99Scores 4.0

Warranty & Support112 months on the US product page, the shorter of FOSSiBOT's two US terms

Policy: FOSSiBOT's US warranty policy lists all solar panels at 2 years

Better on warranty & supportJackery SolarSaga 500 X Bifacial Portable Solar PanelThe product page. $799Scores 6.0

Price

List: $499.00 at us.fossibot.com
Kit: F2400 with 1 x SP420 $1,078.00 and F1800 with 1 x SP420 $878.00 at us.fossibot.com

Summary

Big efficient panel, conflicting short warranty

What it is: a 420 W four-section ETFE folding panel with four kickstands and a cord pocket
The trade-off: high output and efficiency for a folding panel, but heavy, with no output guarantee and conflicting warranty terms
Not checked: the temperature coefficient and bypass diodes; FOSSiBOT publishes neither for this panel
Look elsewhere for: an output guarantee, a clear multi-year warranty or a lighter panel

Strengths

High output from one folding panel
High module efficiency for a folding panel
Four kickstands for a steady stand
Scratch-resistant ETFE front
Zip pocket stores the cords

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Drawbacks

Warranty pages disagreeand the shorter term counts
No power-output warranty
Heavy to carry alone
No station adapter cable listed
No temperature coefficient published
US spec table misprints the current at maximum power

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Social score

5.7 out of 10

RedditNot scored

The Reddit pool is blank: no Reddit thread by an owner of a FOSSiBOT SP200 or SP420 panel turned up in search (October 2026).

GoogleBrand-level6 out of 10

Best Batteries, an Amazon-affiliate review site: the SP200 gave up to 160 W (80 percent of rating) under clear high-summer sun, 78 W in low winter sun and about 25 W under dense cloud, rated 3.9 of 5 (September 2026)
Caveat: the site earns from Amazon links and gives its figures as reported cases, not its own bench test, and flags the SP200's weight and short warranty (September 2026)

YouTube6 out of 10

Liked

Pulled 288 W in low late-afternoon sun (tester)

Read the full summary

A Florida tester's F1800 and 420W solar test: read 288 W from the SP420 at about 3 pm with the sun low, and refilled an F1800 from 50 to 85 percent in about an hour (October 2026)
Tie: FOSSiBOT sent the unit for review, unpaid, and the description carries store links and discount codes, so it is not independent (October 2026)

AmazonBrand-level5 out of 10

Amazon US: the SP200 listing holds 2 ratings averaging 3.8 and the SP420 listing 1 rating at 5.0, both sold by FOSSiBOTDirect Store (October 2026)
Complaint: a verified SP200 buyer cut his review to 2 stars after a few months, saying the cloth kickstand hinges tore and output fell over time (September 2023)

User reviewsNot scored

The retailer pool is blank: Walmart's listing of the 200 W panel holds 1 review, and no Home Depot, Lowe's, Best Buy or REI listing of either panel was found (October 2026).

Trustpilot

Trustpilot rates Us Fossibot (us.fossibot.com) 3.8 from 10 reviews on a claimed page with only one review labelled Verified, 20 percent five-star and none one-star (October 2026).

Track record

No BBB listing for FOSSiBOT or its US store turned up in a BBB search (October 2026).
No CPSC or Health Canada recall names any FOSSiBOT product, its SP200 and SP420 solar panels included, searched in October 2026.

Not countedExcluded

Not counted in any pool: us.fossibot.com's own reviews and entries reposted from it, FOSSiBOT's Facebook Community group, its YouTube channels and its staff posts, all first-party.
Also not counted: FOSSiBOT's affiliate program and creator discount codes, reviews flagged Incentivized at Walmart, and anything gathered in FOSSiBOT promotions.
The retailer pool is blank: no Walmart, Home Depot, Lowe's, Best Buy or REI listing of the SP420 was found (October 2026).

Summary

Brand-level

3.8 on Trustpilot, no BBB rating

Specs

CapacityNot applicable
AC OutputNot applicable
System VoltageNot applicable
Panel Power400 W or more
Charge CurrentNot applicable
Safety ListingNone verifiable
Low-Temp ChargingNot applicable
Warranty1 Year
MonitoringNot applicable
Weight30.8 lb

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Not published by FOSSiBOT: cell type.

At a glance

21.65 x 40.79 in folded
38.4 V open-circuit voltage
Zippered cord pocket

Company

The FOSSIBOT trademark in the US belongs to Shenzhen Qichang Network Technology Co., Ltd. of Shenzhen, China.

Where it sells

FOSSiBOT sells FOSSiBOT in the US from us.fossibot.com, whose terms name the operator only as FOSSiBOT, and its Trustpilot page gives an address in Kwun Tong, Hong Kong.
FOSSiBOT sells its 200 W and 420 W ETFE folding panels with a cart at us.fossibot.com and on Amazon US through its own store, sold by FOSSiBOTDirect Store.
FOSSiBOT also sells on Walmart as its own marketplace seller, FOSSiBOT Official, which lists the 200 W panel.

Description

The FOSSiBOT SP420 (model SP420 on its spec table) is a four-section folding panel of monocrystalline cells under a multi-layer ETFE laminate, with four kickstands and a zippered pocket that holds the cords and covers the output port.

It is rated 420 W, with 32 V and 13.1 A at maximum power, 38.4 V open-circuit and 15.7 A short-circuit, and FOSSiBOT markets cell efficiency of up to 23.4%. Unfolded it measures 87.83 x 40.79 in (2231 x 1036 mm), folded 21.65 x 40.79 in (550 x 1036 mm), and it weighs 30.79 lb (13.97 kg).

Its sunlit side is rated IP67 against splashes, though FOSSiBOT says not to leave it in rain, and it is rated to work from −10 to 65 °C (14 to 149 °F). It ends in standard MC4 connectors, and FOSSiBOT says it charges stations whose MC4 input accepts its output; no station adapter cable is listed with it.

FOSSiBOT's US warranty policy gives its solar panels 2 years, but the SP420's own US page lists 12 months. It sells at $499.00 on us.fossibot.com, and the same store sells it in an F2400 kit at $1,078.00 and an F1800 kit at $878.00.