Anker SOLIX C300 vs EcoFlow RIVER 3: the RIVER 3 costs less per watt-hour and gives more watts per dollar

Specifications checked against manufacturer pages on 2026-08-23.

The Anker SOLIX C300 (288 Wh, 300 W) and the EcoFlow RIVER 3 (245 Wh, 300 W), compared on the figures their makers publish. On the normalized ratios, the RIVER 3 costs less per watt-hour ($0.89/Wh vs $1.15/Wh).

Specifications, side by side

Numbered notes below the table give the source location or a caveat for figures that need one; check marks mark the better figure where one can be judged; “Manufacturer does not state” means absent from that maker’s page as of its check date listed under Sources. UPS switchover is how long the outlets go dark when grid power drops.

^* Calculated: rated capacity × an assumed 85–90% conversion efficiency; no maker publishes a usable figure.

Notes on the figures

1. C300, rated capacity: Rated capacity as stated in the manufacturer’s specifications table and in the product name, Anker SOLIX C300 Portable Power Station – 288Wh | 300W.
2. RIVER 3, rated capacity: Specs tab row. Also in headline bullet: “245Wh capacity, 300W rated output, X-Boost up to 600W”.
3. C300, continuous output: Continuous rated AC output shared across all three AC outlets.
4. RIVER 3, continuous output: Specs tab row. Headline bullet calls it “300W rated output”.
5. C300, surge: The 600 W figure is delivered by Anker’s SurgePad boost mode, and the manufacturer’s own comparison chart labels it ‘SurgePad 600W’. It is not a conventional motor-start surge rating and should not be read as one.
6. RIVER 3, surge: Maker lists a conventional “Surge 600W” and separately an X-Boost mode also rated 600W (“With X-Boost technology, it can power 600W heating devices”); X-Boost is a boost mode for resistive loads, not a surge rating.
7. C300, recharge: The manufacturer states only a 0-80% figure: ‘Recharge to 80% in just 50 minutes with a wall outlet.’ A full 0-100% wall recharge time is not stated.
8. RIVER 3, full recharge: Full 0-100% wall recharge. Body copy: “4 charging options, safely charge 0-100% in 1 hr” / “RIVER 3 fast-charges in 1 hour with X-Stream”.
9. C300, cell chemistry: Marketed elsewhere on the same page as LFP batteries.
10. RIVER 3, cell chemistry: Specs tab row. Body copy: “LiFePO4 cells, 10-year lifespan”.
11. C300, cycle life: Cycle count to the point where the battery still holds 80% of its original capacity.
12. C300, cycle life: Taken from the same specification entry as the cycle-life figure.
13. RIVER 3, cycle life: Specs table row ‘Battery Chemistry LiFePO4, 3000 cycles to 80% capacity’; body copy adds: “RIVER 3 has a lifespan of 3000 charging cycles.”
14. RIVER 3, cycle life: Battery Chemistry LiFePO4, 3000 cycles to 80% capacity
15. C300, UPS switchover: The comparison chart on the same page lists this as under 10 ms. Upper bound.
16. RIVER 3, UPS switchover: Upper bound (stated as “<20 ms”). Body copy: “your AC outlet will switch to the RIVER 3 supply in a barely noticeable 20 ms”.
17. C300, expandable: The specifications table shows a dash for both expansion battery quantity and expandable capacity, indicating no expansion battery option for this model.
18. C300, solar input: Maximum via the MPPT solar input, which accepts panels from 11 to 28 V at up to 8.2 A with an XT60 connector.
19. RIVER 3, solar input: Specs tab row. Body copy: “Power up RIVER 3 in as fast as 2.6 hours with 110W solar input.”
20. C300, AC input: Maximum wall (AC) charging input at 120 V.
21. RIVER 3, AC input: Specs tab row. Generator Input row is also “320W, 0-100% in 60 min”.
22. C300, AC outlets: The specifications table lists the three outlets as NEMA 6-20.
23. RIVER 3, AC outlets: Specs tab row.
24. C300, USB-C: Two of the three USB-C ports are rated 140 W each and support two-way fast charging; the third USB-C port is rated 15 W.
25. RIVER 3, USB-C: Single USB-C port, 100W max.
26. C300, app: App control works over Bluetooth or Wi-Fi via the Anker app; the specifications table also lists Mobile App: Yes.
27. C300, noise: As stated by the manufacturer, measured from 3.3 ft away.
28. RIVER 3, noise: Upper bound (stated as “<30 dB”). Body copy: “a volume of less than 30 dB at a distance of 1.5 ft”; footnote 2 says noise data is from lab tests at 89.6°F (32°C).
29. C300, warranty: Stated as a 5-year warranty.
30. RIVER 3, warranty: Not stated on the product page; EcoFlow’s official US warranty-policy page lists the RIVER 3 at 24 months.
31. C300, weight: Net weight of the unit itself.
32. RIVER 3, weight: Specs tab row (net weight). Dimensions row: “10×8.3×4.4 in”.
33. C300, price: Manufacturer’s store price for the standalone unit without a solar panel; no separate sale or strikethrough list price was displayed at the time of retrieval.
34. RIVER 3, price: Price shown for the standalone RIVER 3 option on us.ecoflow.com when checked; the option was marked “coming soon” and showed no strikethrough price, so we treat $219 as the list price.

The same specs, normalized

Ratios, so the bigger unit does not win by default.

Definitions and direction of each ratio: How we verify.

What each one runs, for how long

Calculated, not measured: hours = rated Wh × efficiency ÷ (appliance W × duty); assumptions on How we verify. “Unlikely to start”: start-up surge exceeds the stated surge rating. “Start-up not assessed” appears where the start-up draw meets or exceeds the unit’s continuous rating and the unit states no conventional motor-start surge to check it against (C300); the hours assume the motor starts.

What the differences mean

Price per watt-hour. At the list prices we checked, the RIVER 3 costs $0.89/Wh against $1.15/Wh for the C300. At list the RIVER 3 is $110.99 cheaper ($219 vs $329.99) for 245 Wh vs 288 Wh. Prices move with sales; the ratio moves with them.

Output for the money. 1.37 W/$ on the RIVER 3 against 0.91 W/$ on the C300: if what you need is to run a high-draw appliance rather than to run a small one for days, this ratio is the one to read.

Which one, and for whom

On normalized measures the RIVER 3 leads on cost per watt-hour ($0.89/Wh vs $1.15/Wh) and continuous watts per dollar (1.37 W/$ vs 0.91 W/$). The C300 does not lead on any decided measure. What decides it is the figure your outage actually tests:

• CPAP overnight. Switchover: C300 up to 10 ms, RIVER 3 under 20 ms. A 40 W CPAP runs roughly 5.8–6.3 hr on the C300 and 4.9–5.3 hr on the RIVER 3. Neither covers a full night (8 hr) without a humidifier at this capacity, so here the hours decide, not switchover.
• Keeping a refrigerator cold. Start-up comes first. The C300 states a boost figure rather than a motor-start surge rating; the RIVER 3 states a 600 W surge rating. A full-size refrigerator needs about 900 W to start.
• A multi-day outage with a generator or solar to recharge from. Full recharge: C300 0–80% in 50 min (no full-charge time stated), RIVER 3 60 min. These are not comparable: Anker SOLIX states no full-charge time for the C300.

Related reading

A 245–288 Wh battery cannot do what a gasoline generator does — neither unit’s continuous rating covers a 1,500 W space heater (see the runtime table) — but it also cannot poison a household. Our CPSC revision matrix tracks how the official count of generator carbon-monoxide deaths has changed across report editions, and this page puts every verified unit on the same refrigerator scenario.

Other comparisons with these models

• Anker SOLIX C300 vs Bluetti EB3A
• EcoFlow RIVER 3 vs EcoFlow RIVER 3 Plus

Ordering before a storm? Check the arrival date at checkout — a unit that ships tomorrow can beat a better one that ships next week. Amazon Prime includes fast delivery on eligible items and starts with a free trial; we earn a commission if you join.

Sources and method

• Anker SOLIX C300: manufacturer product page, checked 2026-08-24.
• EcoFlow RIVER 3: manufacturer product page, checked 2026-08-23.

Published specifications only; no bench tests. Method: How we verify. More: Comparisons.