EcoFlow Solar Input Specs: Every Model’s Max Watts & Voltage (2026)

Trying to pair solar panels with your EcoFlow station and hitting a wall of conflicting specs? You’re not alone. EcoFlow publishes the numbers, but they’re scattered across a dozen product pages. This reference puts the solar input specs of EcoFlow’s RIVER and DELTA stations in one place: max watts, voltage range, and max current.

Whether you’re shopping for a first setup, adding panels to a station you already own, or trying to figure out why charging stopped, the numbers below are what you need. Every figure comes from EcoFlow’s user manuals and US product pages, checked on October 3, 2026.

The table below covers EcoFlow’s RIVER and DELTA lineups, including recent models that are no longer sold new but are still widely used (marked with an asterisk). Each row shows the three numbers that control solar panel compatibility: max input wattage, the voltage window your panels must stay within, and the maximum current the input accepts.

RIVER Series: Solar Input Specs at a Glance

The RIVER lineup spans three voltage windows: 11–30V on the RIVER 2 and RIVER 3, 11–50V on the RIVER 2 Max and RIVER 2 Pro, and 11–55V on the RIVER 3 Plus. Every RIVER tops out at 110W or 220W of solar, so a single panel is usually the practical match.

RIVER 2 and RIVER 2 Max: Entry-Level Limits

The RIVER 2 sits at the bottom of the lineup with a 110W cap, an 11–30V window and 8A max current. One 100W panel is the practical match. A bigger panel won’t charge it faster: the controller caps the draw at 110W, and the panel still has to stay within 30V and 8A. EcoFlow now sells this model as the RIVER 2 (240), with the same solar input.

Step up to the RIVER 2 Max (512Wh) and the input doubles to 220W, with current rising to 13A and the voltage window widening to 11–50V. A single 220W panel works cleanly. Two of EcoFlow’s NextGen 220W panels in series (about 43V of open-circuit voltage) also stay within limits, though the 220W cap limits what the second panel adds. EcoFlow’s US store now sells the RIVER 2 Max 500 (499Wh), with the same solar input.

RIVER 2 Pro and RIVER 3 Plus: 220W Sweet Spot

The RIVER 2 Pro (768Wh) and RIVER 3 Plus (286Wh) both accept 220W at 13A, with an 11–50V window on the RIVER 2 Pro and 11–55V on the RIVER 3 Plus. A 220W panel in clear sky can charge the RIVER 2 Pro from flat in roughly four to five hours of strong sun, based on its 768Wh capacity and typical conversion losses. The smaller RIVER 3 Plus fills in about 1.5 to 2 hours, in line with EcoFlow’s “as fast as 1.5 hr” figure.

The RIVER 3 (245Wh) is the outlier: its solar input is 110W, with the same 11–30V / 8A limits as the RIVER 2. A single 100W panel is the practical match. EcoFlow’s US store no longer sells the base RIVER 3 on its own.

For panel recommendations that match these specs, the EcoFlow DELTA 2 solar setup guide covers compatible wattages and connection configs in detail.

DELTA 2 and DELTA 3 Series: Mid-Range Solar Capability

Moving into the DELTA lineup means a jump in both solar input and voltage headroom. Every DELTA 2 and DELTA 3 model uses an 11–60V window, which opens up two-panel series strings. Solar input ranges from 500W on single-input models to 1,600W on the two-input DELTA 3 Ultra Plus.

DELTA 2: 500W Input, 60V Voltage Window

The DELTA 2 (1,024Wh) accepts up to 500W at 11–60V with a 15A current limit. That 60V ceiling changes the wiring math. Two of EcoFlow’s NextGen 220W panels in series reach about 43V of open-circuit voltage (Voc) at 12.4A, both within limits, for up to 440W. A third panel would push the string to about 64.5V, above the limit.

Series wiring is usually the right choice on these stations: two NextGen 220W panels in parallel would add up to about 24.8A of short-circuit current, well above the 15A limit, while a two-panel series string stays within it. Higher voltage also means less current lost over long cable runs. EcoFlow no longer sells the DELTA 2 new in the US; the DELTA 3 that replaced it has the same 500W / 11–60V / 15A input.

DELTA 3 Series: 500W to 1,600W Depending on the Model

The DELTA 3 family does not share one solar spec. The DELTA 3, DELTA 3 Classic and DELTA 3 1500 have a single 500W input (11–60V, 15A). The DELTA 3 Plus adds a second input, for 1,000W in total (2 x 500W). The DELTA 3 Max has one 500W input with a lower 13A limit, while the DELTA 3 Max Plus has two 18A inputs, for 1,000W in total. At the top, the DELTA 3 Ultra takes 800W on one input and the DELTA 3 Ultra Plus takes 1,600W over two.

EcoFlow’s DELTA 3 manuals spell out the limit: the panels’ total open-circuit voltage must stay within 60V, and their total short-circuit current (Isc) within the input’s rating, 15A on most models and 13A on the DELTA 3 Max. That rules out two NextGen 220W panels in parallel on one input (24.8A of Isc). On two-input models, the simpler path is one series string per input. (EcoFlow’s manuals also list a DELTA 3 1000 Air, rated 12–60V and 15A without a published wattage, but it isn’t sold on EcoFlow’s US store.)

To estimate actual charge times based on your panel and conditions, use the solar charge time calculator. The math applies across all brands.

DELTA 2 Max and DELTA Pro: High-Input Territory

DELTA 2 Max: 1,000W Input, Two Full Arrays

The DELTA 2 Max (2,048Wh) has two solar inputs of 500W each, for 1,000W in total, with the same 11–60V window and 15A per input. The simplest full setup is one two-panel series string per input: two NextGen 220W panels in series (about 43V, 12.4A) on each input, for up to 880W.

With 2,048Wh of capacity and 1,000W of input, a charge from flat takes roughly 2.5 to 3 hours of strong sun at full input. Several newer models match or beat that input: the DELTA 3 Plus and DELTA 3 Max Plus also take 1,000W, and the DELTA 3 Ultra Plus takes 1,600W.

DELTA Pro: 1,600W and 150V Ceiling

The DELTA Pro (3,600Wh) introduces a spec that separates it from every model below: a 150V maximum voltage. That ceiling is the key difference. It makes the DELTA Pro compatible with high-voltage residential solar panels that would exceed the 60V limit of the DELTA 2 series.

With a 1,600W input cap and a 15A current limit, the DELTA Pro takes up to three of EcoFlow’s 400W portable panels in series: 3 x 48V gives 144V of open-circuit voltage, under the 150V limit, for up to 1,200W. A fourth panel would push the string to 192V. Two strings in parallel don’t work either: at 11A of Isc per panel, they would reach 22A, above the 15A limit. The 144V figure leaves only 6V of margin at 25°C (77°F), and open-circuit voltage rises as panels get colder (EcoFlow lists -0.33% per °C for its 100W rigid panel but doesn’t publish the figure for the 400W), so in freezing weather a two-panel string (96V) is the safer choice. Whether you’re stacking panels for more voltage or paralleling for more current, the series vs parallel solar panel wiring guide covers the wiring math and what each topology does to your input figures.

DELTA Pro 3 and DELTA Pro Ultra: Two Inputs, Two Voltage Ranges

The DELTA Pro 3 (4,096Wh) has two separate solar inputs. Its high-voltage input accepts 30–150V, 15A and up to 1,600W; its low-voltage input accepts 11–60V, 20A and up to 1,000W. Together they add up to 2,600W, the figure EcoFlow gives as the DELTA Pro 3’s maximum solar input.

EcoFlow’s manual adds an overvoltage margin: the high-voltage input tolerates up to 155V and the low-voltage input up to 62V. Treat those as protection, not targets, and plan your strings around 150V and 60V. See the full specs on the DELTA Pro 3 product page.

The DELTA Pro Ultra, EcoFlow’s whole-home backup system, goes further. Its inverter has a high-voltage input rated 80–450V, 15A and up to 4,000W, plus a 30–150V, 15A input rated up to 1,600W, for 5,600W in total. That’s the highest solar input in EcoFlow’s lineup, and the 80V minimum on the high-voltage input means it’s built for long strings of residential-style panels rather than a couple of portable ones.

What 2,600W Actually Takes in Practice

With EcoFlow’s 400W portable panels, the DELTA Pro 3 tops out well below 2,600W. Three in series fill the high-voltage input to 1,200W (144V, under the 150V limit), and one 400W panel on the low-voltage input adds 400W (48V; two in parallel would reach 22A of Isc, above its 20A limit). That’s 1,600W in total. Reaching the full 2,600W takes panels picked for each input’s voltage and current limits.

At 1,600W of panels, a charge from flat takes roughly 3 to 3.7 hours of strong sun, based on the 4,096Wh capacity and typical losses. At the full 2,600W, it drops to about 1.8 to 2.3 hours.

Minimum Voltage: 30V and 80V on the High-Voltage Inputs

One spec worth flagging: the DELTA Pro 3’s high-voltage input needs at least 30V to start charging, and the DELTA Pro Ultra’s needs 80V. A single 12V-class panel (around 20–22V of open-circuit voltage) won’t start them. Use the DELTA Pro 3’s low-voltage input (11–60V) for small panels, or wire enough panels in series to clear the minimum.

If solar input is one piece of the capacity puzzle, EcoFlow battery expansion options covers the other: which add-on batteries connect to which models.

Understanding the Numbers: Watts, Volts, and Amps Explained

Three numbers appear in every EcoFlow solar input spec. Each one controls a different aspect of panel compatibility. Getting all three right is what makes a setup work. Getting one wrong means either no charging or potential hardware damage.

Max Watts: The Total Panel Ceiling

Max wattage is the soft ceiling on total panel output. The MPPT charge controller (which manages the solar input on every EcoFlow station) simply caps the draw at the rated maximum. Connecting a 600W array to a 500W-rated station doesn’t damage anything, as long as the array stays within the station’s voltage and current limits: the extra 100W of panel capacity goes unused.

In practice, mild oversizing (10–20% above the station’s rated input) is a common way to make up for real-world losses. On a 60V, 15A input, though, the voltage and current limits usually cap the array first: two NextGen 220W panels in series (440W) is the largest string of EcoFlow portable panels a 500W DELTA input takes.

Voltage Range: Why It Controls Panel Wiring

The voltage range is the hard limit. Your panel array’s open-circuit voltage (Voc) must stay within the station’s published min and max at all times. Exceed the maximum and you risk damaging the charge controller. Fall below the minimum and charging simply won’t start.

This is why the voltage window matters more than wattage when selecting panels. Wiring panels in series increases voltage; wiring in parallel increases current. The voltage ceiling of your station determines how many panels you can put in series before exceeding the safe limit.

Max Amps: The Parallel Connection Limit

The maximum current rating governs how many panels can be wired in parallel, and it’s more than a speed cap. EcoFlow’s DELTA 3 manuals ask that the panels’ total short-circuit current (Isc) stay within the input’s rating, so a parallel setup that adds up to more than 15A (13A on the DELTA 3 Max) is outside spec, even if the station would only draw its rated current. Check the Isc on your panels’ label, not just their wattage.

How to Match Panels to Your EcoFlow Station

Knowing the specs is one thing. Translating them into a working panel configuration is where the numbers become useful. Here’s how the matching logic breaks down by station tier.

For RIVER Series Owners: Single 100–200W Panel Setups

On the RIVER 2 and RIVER 3 (30V), stick to a single 12V-class panel (around 20–22V of open-circuit voltage): two in series would reach about 43V. The RIVER 2 Max, RIVER 2 Pro (50V) and RIVER 3 Plus (55V) can take two of EcoFlow’s NextGen 220W panels in series (about 43V and 12.4A, within their 13A limit). A 400W panel (48V) technically fits under the 50V limit of the RIVER 2 Max and Pro, but with only 2V of margin and a 220W cap, it’s a poor match. Parallel wiring keeps voltage in range but adds current: keep the total within 8A (RIVER 2, RIVER 3) or 13A (the others).

In practical terms, a single 220W panel is the most efficient match for RIVER 2 Max, RIVER 2 Pro, and RIVER 3 Plus owners. One panel, one cable, no wiring complexity.

For DELTA 2 and DELTA 3 Owners: Dual-Panel and Beyond

The 60V ceiling is where series wiring becomes practical. Two of EcoFlow’s NextGen 220W panels in series (21.5V of Voc each, about 43V combined) fit comfortably within the limit; a third would reach 64.5V. One 400W panel (48V) also fits, but two in series would reach 96V. On two-input models (DELTA 2 Max, DELTA 3 Plus, DELTA 3 Max Plus, DELTA 3 Ultra Plus), give each input its own string rather than paralleling strings on one input.

What does that look like in practice? On a DELTA 3 Plus, two NextGen 220W panels in series on each input give up to 880W, close to its 1,000W ceiling, with every string well inside the 60V and 15A limits. On a single-input DELTA 3, the same two-panel string tops out at 440W, under the 500W cap.

For DELTA Pro and DELTA Pro 3: Multi-Array Planning

The DELTA Pro’s 150V ceiling opens up high-voltage panel strings. Three of EcoFlow’s 400W panels in series (48V of Voc each, 144V combined) fit under 150V; a fourth doesn’t. Panels sold as “400W” by other brands can have a higher Voc, so check the datasheet before you build a three-panel string, and leave margin for cold weather.

The DELTA Pro 3 gives you two separate inputs to plan around: a 30–150V, 15A string on the high-voltage input and an 11–60V, 20A setup on the low-voltage input. The DELTA Pro Ultra’s 80–450V input is meant for long strings of residential panels. Readers comparing EcoFlow’s solar charging performance against competing brands will find the full breakdown in the best solar generators of 2026 roundup.

Frequently Asked Questions

Final Thoughts

EcoFlow’s solar input specs follow a rough tiering pattern: RIVER models top out at 110–220W with 30V to 55V windows, the DELTA 2 and DELTA 3 families range from 500W to 1,600W with a 60V window, the DELTA Pro takes 1,600W at up to 150V, and the DELTA Pro 3 (2,600W) and DELTA Pro Ultra (5,600W) split their input across two voltage ranges. Capacity and solar ceiling don’t always scale together, so check both before you match panels to a station.

The voltage window is the spec most people overlook. Max wattage sets your charging speed ceiling; voltage determines which panels can be wired in series. Get both right and your EcoFlow station will charge efficiently from whatever array you connect. Get the voltage wrong and you either get no charging (below minimum) or risk controller damage (above maximum).

The EcoFlow DELTA 2 solar setup guide goes deeper on specific panel recommendations and wiring diagrams for the mid-range models. For a full comparison of EcoFlow against competing brands on solar performance, the best solar generators of 2026 roundup covers the full field.

Visit EcoFlow Knowledge Hub →

Originally published: March 31, 2026