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AFAIK, not worth it if your TNB bill is <RM170 per month, especially if it's RM60 per month.

Eg a 7.2kW solar PV system costs about RM24k to install, and will mostly generate about RM300 worth of electricity (= about 700 kWh) per month. If your TNB bill is RM300 per month, you pay nothing to TNB = you save RM300 per month or RM3,600 per year.
....... So, the ROI is about 7 years if your TNB bill is RM300 or more per month, ie RM24,000/RM3,600 = 6.7 years = worth it.

If your TNB bill is RM60 per month (= RM720 per year), the ROI is about 33 years, ie RM24,000/RM720 = 33.3 years = not worth it.
_ _ _ _ _ _

Eg a 4kW solar PV system costs about RM16k to install, and will mostly generate about 400kWh of electricity per month = RM170 TNB bill per month = saves RM2,040 per year.
....... So, ROI is about 7.8 years, ie RM16,000/RM2,040.

If your monthly TNB bill is RM60 per month (= RM720 per year), the ROI is 22.2 years, ie RM16,000/RM720.


Seems, this is mostly a T20 problem, same like buying the more expensive EV cars (>RM100k).

- 4kW

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This post has been edited by lurkingaround: Mar 29 2024, 12:05 AM

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Fyi, beware of low-quality Chinese solar PV panels, .......

https://www.thestar.com.my/business/busines...rce-competition - 2024/04/01 - some- Chinese solar-firms- sacrifice-quality-to-cut-costs -amid-fierce-competition
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Fyi, .......

https://www.thestar.com.my/news/nation/2024...ce-safety-group - 2024/12/13 - solar-panel-generates-live-current-when-exposed-to-sunlight-says-workplace-safety-group
.... According to an alert from Singapore's Workplace Safety and Health Council, electrocution is a major concern during the installation of solar panels.

It had issued an alert in 2023 after a worker died in the island state after being electrocuted while installing solar panels. ...

On Friday (Dec 13), three workers were electrocuted while installing solar panels at the Public Works Department office in Ranau district, Sabah.

The three – identified so far as Wong, 54, Salleh, 34, and Gimbal, 25 – were killed on the spot. ...

Reminder for DIY'ers or self-installers.
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Fyi, .......
.
Protecting Solar Panel Installers from Electrocution

The Singapore Green Plan 2030 aims to deploy enough solar energy to power 350,000 households annually by 2030. To support this goal, more solar panels will be installed and workers must be kept safe while doing such works. Along with falling from height risks, electrocution is a major workplace safety and health (WSH) concern during solar panel installation and maintenance.

There are several good practices companies can adopt to protect workers from solar panel-related electrocution risks:

• Install solar panels as per design, e.g. a photovoltaic (PV) single line diagram.
• Place and secure an opaque cover over each solar panel to prevent the panel being energised while not plugged in.
• Cover all exposed electrical parts such as cables and connectors with an insulated cap to isolate the wire ends/terminals. Workers have been electrocuted even when solar panels were not plugged
in, due to exposed cables.
• Secure loose cables and connector ends away from the conducting medium (such as metal or water), e.g. by securing them under the solar panel.

• Provide workers with electrical-resistant personal protective equipment, such as arc-rated protective clothing, insulated gloves and rubber-soled shoes.
• Report any PV system breakdown or abnormality, or damaged cables/connector to the licensed electrical worker immediately.
www.tal.sg - Tripartite Alliance Limited
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More news update: .......

https://malaysia.news.yahoo.com/three-insta...-065443144.html - Three installers electrocuted putting in solar panels at JKR lot in Sabah - 13 Dec 2024
.... Ranau district deputy police chief DSP Ediansha Endal said that the four had been assigned to the installation project.

“While installing the solar panels using scaffolding at a height of nearly 7.32 meters, one of the panels came into contact with an 11kV high-voltage cable owned by Sabah Electricity Sdn Bhd,” he said. ...
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Solar street lamp also require solar PV panel, .......

https://www.jllelectrical.com.my/showproduc...on-solar-panel/ - BSLIGHT BSSLSL 500W 6000LM 6500K IP67 SIRIM SOLAR LED STREET LIGHT WITH RADAR MODE SENSOR & MONOCRYSTALLINE SILICON SOLAR PANEL

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This post has been edited by lurkingaround: Dec 13 2024, 08:06 PM

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https://www.ecdonline.com.au/content/effici...r-pv-1461855421 - death-highlights-dangers-of-extra-low-voltage-solar-pv- 1 May 2023
Queensland’s Electrical Safety Office (ESO) has investigated the electrocution of a person who was modifying the solar panels on an off-grid solar PV system in a remote area. The deceased was found with significant burns to their hands and fingers. ...
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Under NEM3.0, a 7kW roof solar panel system produces about 800kWh of electricity per month = saves about RM400 in monthly TNB bill for a home that runs 3 aircons nightly and/or charges an EV car overnight weekly, ie 800kWh X RM0.50.

Under the coming ATAP1.0 (from 1 Dec 2025), a similar home as above will save only about RM168 in monthly TNB bill, ie 800kWh X RM0.21.
....... ROI from paying for a 7kW solar system = about RM20k, will be about 10 years, ie RM20,000/RM168 X 12 = 9.9 years = not quite worth it.

Correct.?
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Most houseowners in Malaysia use most electricity at night, eg, cook dinner, wash clothes, watch TV, play computer, sleep in aircon rooms, charge EV car overnight, etc.

12kWp system = produces 1,200kWh per month = 40kWh per day but BESS/battery can only store 32kWh during daytime = about 6-7kWh would be exported to TNB during the day at RM0.21 per kWh under ATAP.

So, ROI is about 86 months or 7 years, not 75 months/6 years. Worth it.?
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This post has been edited by lurkingaround: Oct 17 2025, 09:53 PM

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My bad, you are correct. Thanks for the correction. Eg .......


= a 12.4kWp solar system produces 1,300kWh per month = 43kWh per day but the BESS/battery can only store 32kWh (usable = 30kWh.?) during daytime (for usual use at night) = about 10kWh per day exported to TNB at RM0.21 per kWh, and 3kWh self-use during daytime.

Also, the Tesla Model 3 AWD has a 75kWh battery = needs about 50kWh to charge from 10%-80% overnight but the BESS/battery has only 32kWh (usable = 30kWh.?) stored from daytime = about 20kWh or more will need to be imported from TNB at RM0.40 per kWh.
....... So, an EV car will set back the above ROI from 7 years to about 8 years. Correct.?

Under ATAP, for most households who use most of their electricity at night, the above 12.4kWp solar system with BESS that costs RM45k, can save; ...

- BESS/battery savings per month = 30kWh X 30 = 900kWh X RM0.40 = RM360 ...
- Extra solar E exported to TNB per month = 10kWh X 30 X RM0.21 = RM62 ....
- 3kWh self-use during daytime per month = 3kWh X 30 X RM0.40 = RM36

... can save a total of about RM458 from their monthly TNB bill.

ROI = RM45,000/RM458/12 = about 8.2 years. Correct.?
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This post has been edited by lurkingaround: Oct 18 2025, 01:47 PM

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After NEM contract expires (eg in 2030 for early adopters of NEM 3.0), likely can move to ATAP, esp if you add a BESS/battery.

For most households, ...
NEM = saves more money from your monthly TNB bill.
ATAP with BESS = will save less money from your monthly TNB bill, about 30% less.

Eg for a 12.4kWp Solar system = produces 1,300kWh per month, ...
under NEM 3.0 = can save about RM650 from monthly TNB bill, but ....
under ATAP with BESS/battery = can only save about RM458 from monthly TNB bill.
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This post has been edited by lurkingaround: Oct 19 2025, 02:10 PM

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Most households use most of their electricity at night. The Solar company needs to provide a bigger BESS/battery, eg 48kWh (usable = 40kWh) instead of 32kWh, bc a 12.4kWp system produces about 40kWh-50kWh during daytime or 1,300kWh per month.
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Why need to kasi chan to TNB who made RM4.69 billion net profit in 2024 when consumers are the one who will be forking out RM45k-51k for their 12.4kWp Solar system with BESS/battery under ATAP.?

Also, ATAP ada gomen rebate.?
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Do most households have elders at home.? Do most households use AC during the day.? Do most households have more days during weekday or weekend.?
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AFAIK, a 32kWh BESS/battery only has a normal usable 26kWh for night-time use = similar to charging our smartphones and your EV car from 10%-90% during normal use.

26kWh out of 43kWh is 60% of battery backup/storage during day-time, not 80%, ie 43kWh produced per day by a 12.4kWp Solar system = 1,300kWh produced per month during day-time. .......

https://www.tls-containers.com/tls-blog/max...timal-soc-range - MAXIMIZING BESS PERFORMANCE: THE IMPORTANCE OF AN OPTIMAL SOC RANGE
2/28/2025
.... ​Although a battery can theoretically cycle from 0% to 100% SOC, best practices dictate operating within a narrower range—such as 10%–90% or 20%–80% to minimize stress and extend system life. This operational strategy pays dividends in enhanced reliability, improved safety, and long-term cost savings. By understanding and adhering to these guidelines, BESS operators can maximize the performance and longevity of their energy storage systems, ensuring stable power delivery and reduced maintenance costs over time. ...

Pipul need to know-it-all and be smartest as much as possible before spending about RM50k to pay Solar companies to install a Roof Solar system under ATAP with BESS. Correct.?

Shouldn't battery backup be more than less, eg shouldn't powerbanks for smartphones be more or less power storage.?
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This post has been edited by lurkingaround: Oct 19 2025, 03:51 PM

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How can consumers/solar adopters kill off TNB when it is a GLC because governments are much more powerful than consumers/solar adopters.?

My main point is that consumers/solar adopters should know-it-all and be smartest as much as possible before spending about RM50k to pay Solar companies to install a 12.4kWp Roof Solar system under ATAP with BESS.
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You are recommending pipul to not follow best practice wrt BESS that use LFP batteries. .......

https://www.batterytechonline.com/ev-batter...charging-habits - New Study Raises Questions About LFP Battery Charging Habits
Charging LFP batteries to 100% might not be as harmless as once thought, according to a new study that challenges conventional EV wisdom.
- 26 Aug 2024

https://www.bstess.com/news/should-you-char...onsumers-guide/ - Should You Charge LFP Battery to 100% Daily? A Consumer’s Guide
Lithium iron phosphate (LFP) batteries, often used in electric vehicles (EVs), solar energy storage systems, and other high-capacity applications, have garnered significant attention due to their safety, durability, and environmentally friendly properties. But when it comes to charging these batteries, one common question arises: Should you charge your LFP battery to 100% every day? ...

.... LFP batteries, like all rechargeable batteries, degrade over time. However, the rate of degradation can be influenced by several factors, including how you charge and discharge the battery. The following factors will help you understand how to extend the lifespan of your LFP battery.

1. Frequency of Full Charges

Charging your LFP battery to 100% occasionally is fine, but doing so regularly can result in a higher rate of degradation. By limiting full charges to only when necessary (e.g., for long trips in an EV), you can slow down this process. In general, the fewer times you charge a battery to 100%, the better for its long-term health.

2. Avoid Deep Discharges

While it may seem intuitive to let your battery drain to 0% to “get more use out of it,” deep discharges can also harm the battery. For optimal lifespan, try to keep the charge level above 20%. Charging between 20% and 80% (or 90%) is often considered the sweet spot for most battery chemistries, including LFP. ...
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So, why you recommend pipul follow harmful or not best practices.? Eg your recommendation will result in pipul spending more money to pay Solar companies to replace their BESS/LFP batteries sooner.
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This post has been edited by lurkingaround: Oct 19 2025, 04:50 PM

In that case, ROI will be >10 years under ATAP with BESS.
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So, I recommend pipul to follow best practices and wait until prices of solar PV panels and BESS batteries drop by at least 30% before adopting it for their homes if under ATAP with BESS.
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Fyi, .......

From Hoymile BESS/battery Warranty pdf, .......

Hoymiles
https://www.hoymiles.com › downloads › hoymi...
PDF
The effective warranty period starts from the earlier of: (1) 4 months from the date the products are shipped from Hoymiles;. (2) the installation date of the ...

1.2 Standard Performance Warranty

Hoymiles warrants that the battery system retains either Seventy Percent (70%) of Designed Energy for Ten (10) years, or for
a Minimum Through Output Energy which is calculated from the
Warranty Effective Date
The Minimum Through Output Energy means the total output energy of the product recorded in the control module of the
product.
The Usable Energy and Minimum Through output Energy for each product model are set out in the table below:

Model No.	Designed Energy (kWh)	Usable Energy (kWh)	Minimum Through Output Energy (MWh)
HB-(10-23)S-G2	11.52/15.36/19.2/23.04	10.05/13.4/16.76/20.11	33.21/44.28/55.35/66.42

1: 90% DoD with 97% Round Trip Efficiency. Usable Energy (kWh) is measured using the testing conditions and methods in
Appendix A
2: In ten years, the total yield energy calculated based on Usable Energy. This number is calculated based on condition @
T=25 deg C, 0.5C/0.5C charging and discharging at roughly 1 cycle per day.

= the Hoymiles BESS/battery's BMS auto-regulates the battery to 90% DoD or Depth of Discharge = usable energy is 90% of rated battery, eg a 32kWh BESS battery has a usable energy of 28.8kWh.
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This post has been edited by lurkingaround: Oct 19 2025, 06:30 PM

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"Sikit sikit, lama lama jadi bukit." = that can be how TNB earned a net profit of RM4.69 billion in 2024. Anyway, .......

https://forum.lowyat.net/topic/5543400 - CATL salt battery 19usd per kilo(watthour) threaten others - today = better specs, similar energy density as LFP battery but 50% cheaper = commercial production by CATL will start in Dec 2025.
= better for consumers/solar adopters to wait for prices to drop before applying for ATAP with BESS/battery.
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This post has been edited by lurkingaround: Oct 19 2025, 07:30 PM