Charging a Power Station with Solar in the Rainy Season and on Cloudy Days

On cloudy and rainy days, solar still charges your power station, but slowly and unevenly. Plan on topping up from the wall whenever the power is on, and treat solar as a bonus during the habagat and typhoon months. On a sunny day, solar does far more.

What to expect under cloud

A panel’s rated watts are measured in strong, standard test light. Under cloud, much less light reaches the cells, so output falls, sometimes to a small fraction of the rating on dark, stormy days. Thin, bright cloud is far better than heavy rain cloud. Output also jumps up and down as clouds pass, which you’ll see on the station’s input reading.

EcoFlow’s own solar charge-time claims are lab or optimal-condition figures. For example, EcoFlow says RIVER 3 (UPS) charges 0-100% on 110W of solar “in as fast as 2.6 hr”, and DELTA 3 fills on 500W of solar in 130 minutes. In rainy-season weather, expect much longer.

Your station’s solar cap still applies

Each station has a maximum solar input. A bigger panel can’t push past it:

On cloudy days, a larger panel within these limits may keep input closer to the cap more of the time. One verified example: a single 220W NextGen panel on a RIVER 2 Max (usable 220W, within the 13A limit). On a DELTA 3, four 125W bifacial panels in parallel (500W usable) are a verified fit. Only use pairings that our checks show as within the limits. Mismatched panels can exceed the voltage or current limit.

Getting the most from weak light

• Aim carefully and re-aim often. Small angle gains matter more when light is scarce. See how to angle a portable panel.
• Avoid shade completely. Under cloud, a shadow from a grille or wire costs even more of a weak signal.
• Use the breaks. Set the panel out when the sun appears between showers, and bring it in when rain starts.
• Cut your load. Run fans, lights and Wi-Fi rather than high-watt appliances, so the little solar you get goes further. Check runtimes with the EcoFlow runtime calculator.

Backup charging from the wall

Wall (AC) charging is much faster than portable solar. EcoFlow lists these AC charge figures:

• RIVER 2: 360W max AC input, 0-100% in 60 minutes.
• RIVER 3 Plus: 360W max AC input, 0-100% in 1 hour.
• DELTA 3: 1500W AC input, 0-100% in 56 minutes.

During rotational brownouts, plug in as soon as power returns, so you start each outage full.

Typhoon safety

Before a typhoon, charge every station and power bank from the wall, then bring folding panels indoors. Wind can lift and throw a portable panel, and a flying panel is dangerous. Keep the station dry and off the floor if your area floods. Don’t handle panels, cables or connectors that are wet or lying in water. More detail in our typhoon prep guide.

Plug-and-play portable panels can be set up by the owner following the manual. Anything wired to the house, a breaker panel, the roof or the grid needs a licensed electrician or PEE and an LGU electrical permit.

What to buy

• RIVER 2 Max (220W solar cap): Shopee · Lazada
• EcoFlow 220W panel for it (single panel, MC4-to-XT60i cable included): Lazada
• DELTA 3 (500W solar cap): Shopee · Lazada
• EcoFlow 125W Bifacial panels (up to 4 in parallel on DELTA 3, daisy-chained with their own leads): Lazada · Shopee

Check today’s price before you buy.

Bottom line

Cloudy-day solar is slow, so lean on wall charging during the rainy season and keep solar as a top-up. Stay within your station’s solar cap and limits, aim carefully, and bring panels indoors before a typhoon.