FAQ
TL;DR: A carefully matched 10 kW inverter can turn 8.4 kW of panels into roughly 33 kWh per sunny day (≈3.9 kWh/kWp) [Elektroda, Nowicjusz17, post #18235924] "It works ;)" [Elektroda, reaven22, post #18236272] Choose models with NC RfG compliance to avoid 0.7 grid derating [Elektroda, noja102, post #18233851] Used SMA or Fronius units still reach 97 % efficiency at €1 000-1 500 (Fronius Symo Datasheet).
Why it matters: Selecting the right inverter protects yield, warranty, and grid approval for years.
Quick Facts
• NC RfG certification is mandatory for ≥10 kWp systems in Poland/EU [Elektroda, StanislawKar66, post #18843734]
• Typical Euro-efficiency for quality 10 kW units: 97 – 98 % (*Fronius Symo Datasheet*).
• New budget 10 kW inverter prices: €1 600 – 2 200 (Growatt, GoodWe) [MarketWatch 2023].
• Used premium inverters: €800 – 1 500 (SMA STP-10 000TL, Fronius Symo) [eBay Sales Data 2024].
• Common grid-fault cutoff band: 195-253 V single phase / 340-440 V three phase (*EN50438*).
Which 10 kW inverters are both affordable and proven?
Forum users praise Growatt, Afore, Sofar, GoodWe, Solax, SMA, Fronius and Huawei; Chint Power and Lumel offer Polish support [Elektroda, noja102, post #18233851] Prices start near €1 600 new and €900 used.
Why must my inverter have NC RfG certification?
Grid operators may derate non-compliant systems by 30 % (0.7 factor) when capacity exceeds 10 kWp [Elektroda, noja102, post #18233851] NC RfG ensures legal connection and remote control capability.
Are used inverters a safe choice?
Used SMA, Fronius, ABB and Huawei units get strong repair and parts support [Elektroda, noja102, post #18243008] Check hours run, warranty transfer, and DC insulation test before buying.
How many MPPT inputs do I need for two 15-panel strings?
Two MPPTs match two strings and prevent mismatch losses; Danfoss TLX Pro+ 15 kW offers three MPPTs for future expansion [Elektroda, Tech132, post #18233601]
Expected daily yield from 8.4 kW south-facing array?
Real user logged 33 kWh on a clear day, equating to 3.9 kWh/kWp [Elektroda, Nowicjusz17, post #18235924] Seasonal averages fall to 1.2 kWh/kWp in winter (PVGIS).
What causes the GridVOutofLim error on Chint?
The inverter trips when phase voltage exceeds its 340-440 V three-phase window; forum values at 398-410 V approach the high limit [Elektroda, Bakalo, post #18242685] Tight utility voltage or wrong country code also trigger it.
Does Chint Power include Wi-Fi monitoring?
Early 4.4 – 4.6 kW units shipped without Wi-Fi; data logging via Ethernet works fine [Elektroda, 3301, post #18236220] Newer 10 kW models bundle a Wi-Fi stick according to the supplier (Chint Datasheet).
Is a fanless inverter better?
Fanless design means silent operation and no dust ingress; users note zero overheating on Chint Power [Elektroda, Jur-ex, post #18236109] Heat sinks must be kept unobstructed.
How to set EN50438 parameters on a Chint inverter?
- Enter installer menu with code 001.
- Select Grid-Code → EN50438.
- Save and reboot.
The unit now respects EU voltage/frequency limits (Chint User Manual).
Can I expand from 8.4 kW to 10 kW on the same inverter?
Yes, choose models with 15 % overload capacity or ≥11.5 kW DC rating; Danfoss FLX17 kW gives ample headroom [Elektroda, Tech132, post #18233601]
How do I keep my inverter from overheating?
Mount in shade, allow 15 cm clearance, and avoid garages that trap heat; an Elnix ran hot indoors [Elektroda, Nowicjusz17, post #18235997]
Edge case: what if my inverter squeaks?
Continuous audible squeal often signals coil vibration or undersized filter; one Elnix did this from new at PLN 3 800 [Elektroda, Nowicjusz17, post #18235997] Warranty replacement or damping compound fixes it.
Typical warranty length for 10 kW inverters?
Budget brands give 5 years; premium models offer 10 years extendable to 20 for ~€350 (Fronius Warranty Guide).
What efficiency should I look for?
Aim for Euro-efficiency ≥97 %; SMA STP10-000TL hits 97.3 % (SMA Datasheet). Lower than 95 % erodes yield.
Where can I buy discounted stock?
Users found new-old-stock Chint units on OLX for PLN 1 399 [Elektroda, Jur-ex, post #18236617] Check local classifieds and installers clearing warehouses.