Solar panels + cold = A potential problem

Solar panel behavior in cold temperatures

• Multiple comments clarify that panel voltage rises as temperature drops; power electronics may see significantly higher voltage than the “nameplate” value at 25 °C (STC).
• Explanation via diode physics: each cell’s forward voltage increases slightly per °C drop; in long series strings this adds up to tens of volts.
• MPPTs normally operate panels below open‑circuit voltage; when current demand is low (e.g. battery full, dawn, cold clear morning), panel voltage can climb to the true cold‑Voc and exceed downstream limits.

EcoFlow / inverter design and protection

• Many argue the core failure is that the device’s “150 V max” rating is effectively an absolute rather than a safe working limit.
• Criticism that there’s inadequate overvoltage protection: no external fuse, crowbar, relay, or dedicated shutdown path to protect the main DC‑DC stage.
• Discussion of MOSFET/IGBT voltage ratings and usual engineering practice: you normally design with generous headroom, not right at abs‑max.
• Some suspect the marketing simply used the component abs‑max as the advertised limit, rather than a derated “recommended max”.

Responsibility: users vs manufacturer

• One camp: this is on the manufacturer. Advertising 150 V max, then blaming users who wire 4× ~37 V panels (≈148 V at STC) is seen as unreasonable for a consumer product.
• Counter‑camp: solar is not plug‑and‑play mains; installers are expected to read datasheets, apply temperature coefficients, and design margin. Running any system at 95–100% of its rating is considered poor practice.
• Several note that EcoFlow products are marketed as easy, “plug & play home backup”, so consumers will reasonably expect car‑appliance‑like simplicity rather than needing PV design training.

Specs, standards, and labeling

• Panels are standardized around STC (25 °C, 1000 W/m²) and provide Voc, Isc and temperature coefficients. Many argue this is adequate for professionals but opaque for casual buyers.
• Some suggest panel labels should include “worst‑case” Voc at a reasonable low temperature (e.g. −40 °C), or installers should be forced by code to use those calculations; others say this is already in NEC/CEC guidance.
• Debate over whether open‑circuit voltage is de‑facto treated as “maximum” by many users, even though it isn’t a hard upper bound.

Better engineering approaches

• Suggestions: crowbar+fuse, high‑voltage relays or MOSFET disconnect with analog comparators, or letting the DC‑DC stage safely short the array to clamp voltage.
• Some argue good inverters already disconnect or fault before damage; if a unit simply “lets the smoke out”, that’s a design failure.

Broader solar practice and anecdotes

• Discussion of series vs parallel strings, microinverters vs central inverters, shading behavior, and current vs voltage limits.
• Several anecdotes of blown packs and the culture of “magic smoke” in electronics.
• Meta‑point: as solar moves from niche expert domain to mainstream consumer tech, old “everyone knows this” assumptions about temperature coefficients and safety margins break down.