DELTA Pro Ultra Solar Setup: How to Build Series Strings and Which Panels Work

To set up solar on an EcoFlow DELTA Pro Ultra, wire matching MC4-lead panels in series: 5 to 12 x 160W or 220W NextGen, or 3 to 10 x 400W rigid on the High-PV input (80-450V, 15A, 4000W), or 2 to 6 x 160W/220W, or 1 to 3 x 400W rigid on the Low-PV input (30-150V, 15A, 1600W). Series wiring keeps the current under the 15A limit and lifts the voltage above each input’s minimum.

The three checks every string must pass

EcoFlow’s manual gives each input a voltage range and a 15A limit. We check every string against three rules:

1. Total open-circuit voltage (Voc) stays under the maximum, with a 5% margin: 427.5V on High-PV, 142.5V on Low-PV.
2. Total operating voltage (Vmp) is above the minimum: 80V on High-PV, 30V on Low-PV. Below this, the input won’t charge properly.
3. Current stays within 15A. In series, current doesn’t add up, so one panel’s short-circuit current is the string’s current.

In series, add the voltages. Here are the per-panel figures:

Worked examples

220W on High-PV:

• 4 in series: Vmp 4 x 18.4 = 73.6V. That’s under 80V, so it fails.
• 5 in series: Vmp 92V, Voc 107.5V. Works (1,100W).
• 12 in series: Voc 258V, still far under 427.5V. Works (2,640W). We stop at 12 panels per string.

400W rigid on High-PV:

• 2 in series: Vmp 62V. Fails.
• 3 in series: Vmp 93V. Works (1,200W).
• 10 in series: Voc 371V, under 427.5V, and 4,000W fills the input. Works. An 11th panel adds nothing.

On Low-PV, the 150V ceiling is the limit: 6 x 220W is 129V (works), 7 is 150.5V (fails). Three 400W rigid panels are 111.3V (works); four are 148.4V (fails).

Full range by input

The manual says you can use either input, or both. It doesn’t state a combined maximum, so don’t count on the two totals adding up exactly.

Cold weather: the manual advises against 6, 8 or 10 of the 220W or 400W panels in series at low temperatures (below 0°C). That rarely applies in the Philippines, but in a cold mountain location choose 7 or 9 instead.

Which panels don’t work (or aren’t verified)

• 125W Bifacial and 400W Lightweight: XT60 leads. No official EcoFlow source we found confirms an adapter path to either DELTA Pro Ultra input.
• 45W: DC5521 output, same issue.
• 60W: EcoFlow’s own spec figures for it disagree, so we leave it out.
• Parallel wiring: EcoFlow doesn’t recommend it. Two 220W panels in parallel would be 24.8A, well over 15A. (The spec table also lists 23A short-circuit current, but the manual’s guidance is to stay within 15A.)

Use one panel model per string. Our checks only cover matching panels.

Step-by-step

1. Pick your input and panel count from the table above.
2. Lay out the panels in full sun, with no shade.
3. Join them in series: male MC4 of one panel into female MC4 of the next. Use EcoFlow Solar Extension Cables if leads don’t reach.
4. High-PV: plug the string’s free MC4 leads straight into the High-PV input.
5. Low-PV: connect the string to the Solar to Low-PV Port Charging Cable that comes with the unit, then plug it in.
6. Check the input watts on the screen.

You won’t need the MC4-to-XT60i cable that ships with the 160W and 220W panels.

Safety

Long strings carry high DC voltage: 10 rigid panels are about 371V open-circuit. Fixed rigid arrays, roof mounting and any connection to your house wiring need a licensed electrician and an LGU electrical permit. Foldable panels on the ground are plug-and-play following the manuals, but keep connectors dry and never handle them in the rain.

What to buy

• EcoFlow DELTA Pro Ultra on Lazada or on Shopee
• 5 to 12 x EcoFlow 220W on Lazada, or
• 5 to 12 x EcoFlow 160W on Lazada or on Shopee, or
• 2 to 5 packs of the EcoFlow 400W Rigid on Lazada (2 panels per pack)

Check today’s prices. For ready-made setups and charge times, see the best solar panels for the DELTA Pro Ultra and our DELTA Pro Ultra buyer’s guide.

Bottom line

Count your panels, add up the voltages, and check the minimum. Five foldables or three rigid panels is the smallest High-PV string; twelve foldables or ten rigid panels is the most.