12kW Solar System Explained Step-by-Step ⚡ MPPT, PV Strings, Wiring & Safety Guide

In this video, I explain a complete 12kW solar power system design step by step, based on a real subscriber question from Mihai in Romania.
This tutorial covers everything beginners and DIY solar learners need to know, including system design, MPPT calculations, PV string sizing, wiring, protection devices, and common mistakes to avoid.
🔧 System Overview:
12kW all-in-one hybrid inverter
20kWh battery bank
580W TOPCon solar panels
2 MPPTs (27A each)
8 panels per string
2 strings per MPPT
Total PV power: 18.56kW
📌 What You’ll Learn:
✔ How to size solar strings correctly
✔ Cold-weather voltage (Voc) calculations
✔ MPPT current limits explained
✔ Safe PV oversizing strategy
✔ DC & AC wiring step by step
✔ Cable sizing and MC4 connectors
✔ DC isolators, fuses, SPDs, breakers
✔ Battery to inverter connection
✔ Grid connection & ATS explained
✔ Grounding / earthing requirements
✔ Most common solar installation mistakes
This video is perfect for:
DIY solar learners
Homeowners planning solar
Electricians entering solar
Solar installers & engineers
⚠️ IMPORTANT SAFETY DISCLAIMER
⚠️ Disclaimer:
This video is for educational purposes only.
Solar power systems involve high DC voltage, high current, and grid-connected AC electricity, which can cause serious injury, fire, or death if handled incorrectly.
Always follow:
Local electrical codes and regulations
Utility grid rules
Manufacturer installation manuals
If you are not trained or licensed, do NOT attempt installation yourself.
Always hire a qualified solar installer or licensed electrician.
AK Electric DIY is not responsible for damage, injury, or loss caused by improper installation or misuse of this information.
🛒 AFFILIATE LINKS (SUPPORT THE CHANNEL)
(Some links may be affiliate links. Using them helps support the channel at no extra cost to you.)
🔹 Solar DC Cable (6mm² / 10mm²):
👉 https://amzn.to/3YKzGOb
🔹 Genuine MC4 Connectors & Crimp Tool:
👉 https://amzn.to/45fPSe7
🔹 DC Isolator Switch (500–1000V DC):
👉 https://amzn.to/4qT4QyU
🔹 DC & AC Surge Protection Devices (SPD Type 2):
👉 https://amzn.to/49GUfQO
🔹 Hybrid Solar Inverter 12kW Class:
👉 https://amzn.to/4sJnIlN
🔹 Lithium Battery 48V / 20kWh:
👉 https://amzn.to/4sJnIlN
💬 JOIN THE DISCUSSION
Have a different inverter model?
Comment below with:
Inverter brand & rating
Solar panel wattage
Location / country
I may design your system in a future video.
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