Solar PV System: String Inverter vs Microinverters

In my previous post "How To Choose A Rooftop Solar PV System", I mentioned that the orientation of solar panels might significantly affect the power output of the whole solar PV system with a centralized string inverter.

Besides, solar panels facing west seem to produce more energy compared to solar panels facing south, which contradicts the fact that south-facing is the best orientation for an area located north of the equator.

Anyway, I'm not an expert in this field. I'll just share my layman observation here.

Firstly, even though my house is facing south, it's not 100% south, it's actually about 10-20 degrees to the south west direction. 

The west facing roof is thus slightly tilted toward the northwest direction.

I guesstimate that the roof angle is about 45 degrees which is almost the same for all directions.

I installed 10 solar panels with 3 microinverters:

• 4 panels with 1 microinverter facing south
• 3 panels with 1 microinverter facing west
• 3 panels with 1 microinverter facing west

There are fewer panels facing south because of space limitation on the south-facing roof.

There is a DTU (Data Transfer Unit) that transfers the data from the inverters to the app in my phone. From here I can check the energy & power output of each solar panels and the overall electricity generated in a day.

The DTU is connected to Wi-Fi and turned on 24/7.

How To Choose A Rooftop Solar PV System?

 

Previously I knew almost nothing about home solar PV system, and I thought installing it will cost a bomb.

However, because of significant drop in the price of solar panels & more intense competition among local solar companies, it is getting more affordable.

As it was my friend who first ignited my interest in installing the solar panels under NEM 3.0, initially I decided to appoint the same solar company as he chose.

I got a quotation but then I felt that I should do some research on this matter before I made my decision. It's not a small investment to me.

Luckily I did that.

My Portfolio Sep25

Summary of September 2025

Portfolio @ End of Sep25

 

In Sep25, my portfolio rose 4.9%, which is easily its best performance YTD.

YTD portfolio loss has been narrowed to 6.1% which is the "best" level since Feb25.

KLCI continues its advance in Sep25 with a handsome 2.3% gain. 

I didn't make any transaction this month, and my portfolio was mainly lifted by Eupe, MFCB & Scientex which made more than 10% gain in a month.

Solar PV System (NEM 3.0) under New Electricity Tariff

 

From 1st of Jul 2025 onward, TNB has introduced new electricity tariff which divides the charges into 3 categories:

• Generation charges: Energy Charge, Automatic Fuel Adjustment (AFA) and Capacity Charge
• Network charge: cost of delivering electricity
• Retail charge: cost of billing & customer service

This new structure will be unfair to households with solar PV system under NEM if the solar electricity only can offset the energy charge, as the capacity and network charges are relatively high.

Nevertheless, in the end, fortunately all those charges can be offset one to one.