EcoFlow’s RIVER 3 Max Plus is not a new power station so much as a pairing: the 286Wh RIVER 3 Plus stacked on a 572Wh Extra Battery 600 for 858Wh in total. EcoFlow’s US store lists the bundle under the name “RIVER 3 Max Plus (RIVER 3 Plus + Extra Battery 600),” with the same 600W inverter, 1,200W X-Boost, sub-10 ms UPS switchover and 220W solar input as the base unit. What changes is runtime, weight and how long it takes to refill.
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This review sets out what the bundle includes, the specs that matter, realistic runtimes and the kinds of owner it suits. All specifications come from EcoFlow’s regional product pages and manuals. Runtime and charge figures I calculate myself are labelled as estimates.
What is in the box
You get two pieces that lock together without cables:
- RIVER 3 Plus: the power station itself, with the inverter, all outlets, the solar input and a built-in light. 286Wh, about 10.4 lb.
- Extra Battery 600 (EB600): a 572Wh LiFePO4 pack that sits underneath and connects through contacts on the base. EcoFlow also sells a smaller EB300 at 286Wh.
EcoFlow says the RIVER 3 Plus can take either battery, and stacking the EB600 gives the 858Wh maximum. You can unclip the top unit and carry just 286Wh on a day trip, then reattach it at camp or at home.
Key specifications
| Spec | RIVER 3 Max Plus (RIVER 3 Plus + EB600) |
|---|---|
| Total capacity | 858Wh LiFePO4 (286Wh + 572Wh) |
| Cycle rating | 3,000 cycles to 80%+ |
| AC output | 3 outlets, 600W total, 1,200W surge, 1,200W X-Boost |
| USB-C | 100W (some regional bundles list an added 140W port) |
| USB-A | 2 × 12W |
| Car outlet | 12.6V, 10A, 126W |
| Solar input | 11–55V, 13A, 220W max |
| Car input | 11–55V, 8A, 220W max |
| UPS switchover | <10 ms |
| Noise | <30 dB in quiet use |
| Stacked dimensions | About 234 × 232 × 286 mm (9.2 × 9.1 × 11.3 in) |
| Stacked weight | About 10.8 kg (23.8 lb), per EcoFlow AU |
| App | Wi-Fi and Bluetooth |
| Warranty | 5 years |
Sources: EcoFlow US, AU and Ireland product pages; RIVER 3 Plus user manual. Regional listings vary slightly, so confirm the US spec sheet for your exact bundle.
Runtime: where 858Wh makes the difference
EcoFlow’s own examples for the 858Wh setup are a 3W Wi-Fi router for up to 86.9 hours and a 600W computer for at least 60 minutes. For your own loads, the quick formula is capacity × efficiency ÷ watts. I use 85% for AC loads and about 90% for 12V loads in the estimates below.
| Load | RIVER 3 Plus alone (286Wh) | RIVER 3 Max Plus (858Wh) |
|---|---|---|
| 12V compressor fridge, ~20W avg (12V outlet) | ~13 hours | ~39 hours |
| CPAP, ~40W (AC) | ~6 hours | ~18 hours |
| Starlink Mini, ~30W (AC adapter) | ~8 hours | ~24 hours |
| TV and streaming box, ~100W (AC) | ~2.4 hours | ~7.3 hours |
| Home-office desk, ~150W (AC) | ~1.6 hours | ~4.9 hours |
All figures are estimates. Fridges and CPAP machines vary widely by model and setting, so measure with a plug-in watt meter where you can.
Charging the full stack
The base RIVER 3 Plus refills in about an hour on AC, according to EcoFlow. With the EB600 attached there is three times the energy to replace, and EcoFlow’s regional pages quote about 1.8 to 2.3 hours on AC for the 858Wh setup, depending on the market and charging mode.
Solar is capped at 220W whether or not the extra battery is attached. EcoFlow AU quotes about 4.8 hours at the full 220W for the stack.
Worked example: solar on a camping trip (estimate)
Two 100W panels in series typically deliver around 140W in good sun once heat and angle losses are counted. At 140W, refilling 858Wh takes roughly 6 hours of strong sun (858 ÷ 140). If a 12V fridge uses about 480Wh a day, that same pair of panels can replace a day’s fridge use in about 3.5 hours of good sun, which is realistic on most summer days.
The car input also tops out at 220W, but a standard 12V socket delivers far less, usually around 100–120W. Plan on most of a day’s driving to refill the stack from a car socket (estimate).
Using it as a UPS
EcoFlow rates the switchover at under 10 ms, which keeps most computers, routers and NAS boxes running through a blackout. With 858Wh behind it, the RIVER 3 Max Plus moves from “time to save your work” territory into “ride out a short outage” territory. A 25W modem and router pair could run for roughly 29 hours on the stack (858 × 0.85 ÷ 25, estimate).
Use the app’s charge limits if it lives on the wall full-time. Holding a LiFePO4 pack below 100% is a common practice for long standby use, and the EcoFlow app lets you set an upper charge limit.
Strengths
- Modular. Carry 286Wh or 858Wh depending on the day.
- Wire-free stacking. No cables between the battery and the station.
- Wide solar window. 11–55V accepts two typical 12V-class panels in series.
- Three AC outlets and a built-in light.
- Five-year warranty and LiFePO4 cells rated for 3,000 cycles.
Things to plan around
- The 600W inverter limit stays the same. More capacity does not mean bigger appliances. X-Boost helps heating loads, not motors.
- Solar tops out at 220W. Refilling 858Wh from solar takes most of a sunny day.
- Weight roughly doubles when stacked, to about 10.8 kg.
Who it is for
Good fit: weekend campers with a 12V fridge, van owners who want a compact second battery, home-office users who want hours of UPS rather than minutes, and anyone who wants to start small and grow without buying a second power station.
Look elsewhere: if you need to run a microwave, a hair dryer at full heat or a large tool. For that, a 1,800W-plus class unit makes more sense.
Where to buy
EcoFlow sells the bundle as RIVER 3 Max Plus (RIVER 3 Plus + Extra Battery 600) on its US store.
Related reading
FAQ
What is the difference between RIVER 3 Plus and RIVER 3 Max Plus?
The Max Plus is the RIVER 3 Plus with EcoFlow’s 572Wh Extra Battery 600 attached, for 858Wh in total. Output, ports and solar input are the same.
How much does the RIVER 3 Max Plus weigh?
About 10.8 kg (23.8 lb) stacked, per EcoFlow AU. The RIVER 3 Plus alone is about 10.4 lb.
Can it run a 12V fridge overnight?
Yes. At a 20W average draw, 858Wh covers well over a day before solar (estimate).
Does the extra battery increase output power?
No. Output stays at 600W continuous with 1,200W X-Boost.
How fast does it charge from solar?
Up to 220W. EcoFlow AU quotes about 4.8 hours for the full stack at that input.