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Technical guide · Bilotex
Your inverter decides the entire system
It is the brain of the install: it sets the maximum power, the compatible batteries, the optimizers and even your future expansion. We explain which to pick based on your load, phases and priorities.
The most expensive mistake: picking the wrong inverter
Panel prices fell 80% in 10 years. The inverter still drives most decisions for you — and getting it wrong locks tens of thousands of € in future upgrades.
Buy a single-phase inverter for a high-load house (>15 kWh/day) and you'll run out of margin the moment you add AC or an EV — you'll have to replace it.
Pick a closed-battery brand (Huawei, SolarEdge) and you can't pair it with cheaper Pylontech or Growatt banks.
Pick pure string with no battery input ('hybrid'), and adding storage later means a second device + more wiring. Better to decide right on day 1.
3 inverters · 3 use profiles
The 3 brands that cover 70% of Spanish residential. This is exactly the logic our calculator uses when it picks automatically:
Huawei SUN2000
For mid-size homes with Huawei batteries
€1 200-3 500
- Native hybrid — battery input + integrated MPPT optimizers
- FusionSolar app (best monitoring on the market)
- Compatible ONLY with Huawei LUNA2000 batteries (HV)
- 1-phase 3-12 kW, 3-phase 5-20 kW
- #1 residential brand in Spain 2024
Deye SUN-K-SG
For larger 3-phase houses
€1 800-5 000
- Reference hybrid 3-phase (5-50 kW)
- Open batteries: Pylontech / Growatt / Huawei (all LV!)
- UPS function — house keeps running through outages
- Great Modbus protocol for Home Assistant integrations
- Best €/kW in the professional segment
Growatt MIN/MID/MOD
For simple residential self-consumption
€900-2 800
- Huge catalog: 1-phase 3-10 kW, 3-phase 5-25 kW
- Own ARK (HV) and AXE/APX (LV) modular battery banks
- ShineWiFi-X dongle for cloud monitoring
- European pioneer with extensive service network
- Best option when budget is the top priority
Which to pick by use case?
Golden rule: match the inverter to real needs, don't buy the cheapest.
What separates a decent inverter from a mediocre one
Hybrid from factory
Built-in battery input. If you want storage later, no need to replace anything.
UPS / EPS function
On a power cut it keeps essential outlets alive from the battery. Critical in rural areas.
Open communication
Open Modbus TCP / RS485 = integration with Home Assistant, Loxone or any home automation.
Decent native app
A good app (FusionSolar, SolarMAN, ShinePhone) is the difference between enjoying or ignoring the system.
Frequently asked questions
How much inverter power do I need?+
Rule of thumb: the inverter should be ≈ 80-100% of panel peak. For 6 kWp panels a 5-6 kW inverter is ideal. Oversizing wastes money.
Hybrid or string + external battery charger?+
If you're sure you'll add a battery (now or in 1-2 years), buy hybrid. It's €200-400 more but saves you a separate charger (€1 500) and simplifies wiring.
Single-phase or three-phase?+
If your grid connection is 1Φ (<6 kW contracted), you don't need 3Φ. Above 9.2 kW of generation or with a 3Φ house, go straight to three-phase — Spanish grid code requires it for balance.
What does Bilotex recommend by default?+
Our calculator picks Huawei or Growatt for small/mid homes with battery, Deye for 3Φ or large systems, and SolarEdge only when shading is complex. The engine is Python — no commercial bias, optimized for actual compatibility.
Calculate your system with the right inverter
Tick your loads and priorities — the calculator picks the inverter that fits your phase, battery and budget in 10 seconds.
Open the free calculator