Choosing between the EcoFlow River 3 and the Anker SOLIX C300 DC is a desk-size backup fork. River 3 is a 245Wh LiFePO4 station with a 300W AC inverter (X-Boost up to 600W for some resistive loads), a claimed under-20 ms UPS handoff on AC, and a built-in AC charge path. C300 DC is a 288Wh LiFePO4 DC-only brick with strong USB-C output (including two 140W bidirectional ports), a 12V car socket, no AC outlets, and no wall charger in the box. Specs and street prices below come from manufacturer sheets and current Amazon listings, not a lab shootout.
This head-to-head sits next to Best Compact UPS Units Under $150 for a Desk NAS, Mac mini M4 Plex Server Kit with a Compact UPS, and Quiet Under-Desk NAS Kit for Plex and Backups. For a quieter apartment NAS path see Quiet NAS for an Apartment Plex Setup, and for a current 4-bay box see the Synology DS925+ Review.
| Attribute | EcoFlow River 3 | Anker SOLIX C300 DC |
|---|---|---|
| Rating | 4.3 | 4.4 |
| Price | $219approx. · checked Sep 2026 | $199.99approx. · checked Sep 2026 |
| Battery | 245Wh LiFePO4 | 288Wh LiFePO4 |
| AC output | 300W (X-Boost up to 600W class) | None (DC only) |
| UPS-style AC handoff | Under 20 ms (maker claim) | N/A (no AC outlets) |
| Standout DC ports | Mixed USB alongside AC outlets | 2x 140W USB-C bidirectional + car socket |
| Total output class | 300W AC + USB | 300W DC total |
| Weight | About 7.8 lb | About 6.17 lb |
| Wall charger in box | AC charge path included | No (USB-C PD charger separate) |
| Best for | Desk AC UPS backup | USB-C laptop DC brick |
| Buy | View on Amazon | View on Amazon |
Quick verdict
Most home desks that want to keep a router, ONT, or small AC wall-wart stack alive through short outages should buy the EcoFlow River 3. The AC inverter and under-20 ms UPS claim match that job. The Anker SOLIX C300 DC is the smarter spend when the entire desk load is USB-C laptops, phones, and 12V accessories, you value the extra 43Wh and lower weight, and you accept buying or reusing a USB-C PD charger.
Capacity and runtime
Winner: C300 DC on Wh; River 3 when AC loads matter. Anker lists 288Wh. EcoFlow lists 245Wh. On paper, C300 DC stores more energy for DC devices. Runtime still depends on draw: a 30W router-class load and a 60W laptop pull very different hours. If the critical loads need AC, River 3's inverter is the enabling feature even with fewer Wh.
AC inverter and UPS behavior
Winner: River 3 (C300 DC has no AC). EcoFlow rates River 3 at 300W AC continuous with X-Boost up to 600W for some higher-draw devices, and advertises UPS-style switching in under 20 ms on the AC path. C300 DC is DC-only: USB-C, USB-A, and a 12V/10A car socket, with no AC outlets and no AC UPS mode. Amazon marketing copy that mentions UPS for C300 DC does not add wall outlets. Buy River 3 when wall plugs must stay up. Buy C300 DC when every device already charges over USB-C or 12V.
USB-C ports and desk charging
Winner: C300 DC for multi-USB-C desks. Anker lists four USB-C ports including two 140W bidirectional ports, one 100W USB-C, one 15W USB-C, two 12W USB-A ports, and a 120W car socket, for up to 300W total DC output. River 3 focuses on mixed AC plus a smaller set of USB ports for phones and laptops alongside its AC outlets. If the job is powering two USB-C laptops and accessories without an inverter, C300 DC matches better.
Size, weight, and recharge
Winner: C300 DC for packability; River 3 for plug-and-charge AC refill. Anker lists about 6.17 lb and roughly 4.9 x 4.7 x 7.9 in. EcoFlow lists about 7.8 lb with a built-in handle. River 3 supports about 1 hour AC recharge (0-100% class claim) with its X-Stream path and optional solar. C300 DC recharges over USB-C PD (wall charger not included; dual 140W input for fastest refill) or up to 100W solar via XT60. Plan on owning a capable USB-C charger if you pick Anker.
| Axis | EcoFlow River 3 | Anker SOLIX C300 DC |
|---|---|---|
| Battery | 245Wh LiFePO4 | 288Wh LiFePO4 |
| AC output | 300W (X-Boost up to 600W class) | None |
| UPS-style AC handoff | Under 20 ms (maker claim) | N/A (no AC) |
| Standout DC ports | Mixed USB + AC focus | 2x 140W USB-C bidirectional + car socket |
| Weight | About 7.8 lb | About 6.17 lb |
| Wall charger in box | AC charge path included | No (USB-C PD charger separate) |
| Typical street price | About $210 to $250 | About $200 |
| Best fit | Router/AC desk UPS backup | USB-C laptop DC brick |
Price and value
Winner: Tie on street price; pick by port mix. Recent Amazon pricing puts C300 DC near $200 (list often higher) and River 3 near $210 to $250. Neither is a bargain classic UPS. River 3 wins value when you would otherwise buy both a UPS and a USB power bank. C300 DC wins when you already have USB-C chargers and never need AC.
Who should buy which
Buy the EcoFlow River 3 if you need AC outlets, want a short UPS-style handoff for a modem/router or small wall-wart stack, and prefer AC wall recharge without hunting for a 140W USB-C brick.
Buy the Anker SOLIX C300 DC if every critical load is USB-C, USB-A, or 12V, you want more Wh in a lighter body, and you already own (or will buy) a strong USB-C PD charger.
Skip both if you need hours of runtime for a NAS, desktop PC, and monitor. Use a larger UPS or a higher-Wh power station with a real AC inverter sized for that load.
Bottom line
River 3 and C300 DC sit in the same price band but solve different desk outage problems. River 3 wins overall for most home desks that still have AC wall-warts and want UPS-style continuity. C300 DC wins for USB-C-first travel and laptop kits that never need an inverter. Specs here are from maker sheets and Amazon listings, not a lab shootout. Confirm current street pricing, then View on Amazon before you order.
For a traditional UPS shortlist aimed at a quiet NAS, see Best Compact UPS Units Under $150 for a Desk NAS. For a Mac mini Plex kit that pairs with a UPS, see Mac mini M4 Plex Server Kit with a Compact UPS.
