Normalized comparison

RIVER 3 vs 521

Green cells mark a meaningful category leader. Ties are shown as shared leaders.

Best for home backupEcoFlow RIVER 3

Capacity, output, expansion, UPS, charging and longevity. Rule score: 78/100.

Best for portabilityEcoFlow RIVER 3

Weight, energy density, charge speed, size and output. Rule score: 54/100.

Best for solarEcoFlow RIVER 3

Solar input, capacity, charging, longevity and weight. Rule score: 83/100.

SpecificationEcoFlow RIVER 3Anker 521
Capacity245 Wh256 Wh
Estimated usable208 Wh218 Wh
Continuous output300 W200 W
Surge output600 W450 W
AC outlets22
Battery chemistryLiFePO₄LiFePO₄
Cycle life3,000 cycles3,000 cycles
AC full charge1 hr4.1 hr
Solar input110 W120 W
Weight7.8 lb8.2 lb
UPS20 msNo
ExpandableNoNo
Warranty5 years5 years
MSRP reference$239—
Where to buy
Check price at manufacturer · EcoFlow USExact product listing at EcoFlow US — availability may change
Check Price on Amazon.comExact product listing at Amazon US — availability may change
Check price at manufacturer · Anker SOLIX USExact product listing at Anker SOLIX US — availability may change
Check Price on Amazon.comExact product listing at Amazon US — availability may change

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