1 hour ago, BritManToo said:

Disagree,

You calculate your installation to cover average loading then use the grid to top up.

Don't even need a battery, use the grid as your battery (slightly naughty but cost effective), as long as you don't show negative on meter reading day (or the meter spinning backwards). I just plug in my EV on meter reading day, so the reader only ever sees the meter running in the right direction.

500bht bill last month for a 3 bed house (one aircon), electric car (1,000Km), and my electric MTB (450Km).

On a 20kbht DIY solar install. Breakeven time around 18 months.

This will be an unpopular post but your setup is probably the only type of setup that will see a ROI. Some good and knowledgeably posters on this forum have calculated ROI using math that isn't even close to reality.

The math is simple. How much you consume each month and if 100% of that is produced by Solar and ESS, multiply by PEA's rate. Regardless if you have an EV or whatever. That number is what it would cost using PEA without solar. It is a pipe dream for most to think they will ever get a return on investment.

Throw in time value of money at 5% and depreciation and the calcs even look more ridiculous.

I use more power than most ( not saying the most or even close) because of an EV and have been averaging about 900 kWh the last few months. 900x4.5 =4050 baht savings. I might get a return on my investment because of my inexpensive install but I'm not holding my breath or really care.

Solar is fun and so are EVs. That is enough for me ;)

9 minutes ago, Packer said:

Yes.

Professionally installed system that obviously meets all the requirements already, as it was installed by professionals using certified approved systems, officially registered, and requires no additional expansions or adjustments within the next 10 years.

Service cost of the official check inc. 7% Vat (in Kw) : 972

Contract duration: 10 years (triple digits in months)

Time to supply 972Kw to the grid: A single digit in months.

🙂

still waiting. Size of the system and cost. You embarrassed? I bet you can't even produce 5 kWh above what use. Show us your numbers.

7 minutes ago, atpeace said:

The math is simple. How much you consume each month and if 100% of that is produced by Solar and ESS, multiply by PEA's rate. Regardless if you have an EV or whatever. That number is what it would cost using PEA without solar. It is a pipe dream for most to think they will ever get a return on investment.

I'm aiming for the 3bht a unit rate for users consuming under 200 units a month.

Thought it was starting in June (125 units), but were still charging me 4bht ...........

Edited July 4Jul 4 by BritManToo

15 minutes ago, atpeace said:

This will be an unpopular post but your setup is probably the only type of setup that will see a ROI. Some good and knowledgeably posters on this forum have calculated ROI using math that isn't even close to reality.

Forumsoftware solutions

The math is simple. How much you consume each month and if 100% of that is produced by Solar and ESS, multiply by PEA's rate. Regardless if you have an EV or whatever. That number is what it would cost using PEA without solar. It is a pipe dream for most to think they will ever get a return on investment.

Throw in time value of money at 5% and depreciation and the calcs even look more ridiculous.

I use more power than most ( not saying the most or even close) because of an EV and have been averaging about 900 kWh the last few months. 900x4.5 =4050 baht savings. I might get a return on my investment because of my inexpensive install but I'm not holding my breath or really care.

Solar is fun and so are EVs. That is enough for me ;)

Even more unpopular my claim is

This is not only about ROI or freedom to change your own system.

It is also about the difference between a legal solar system approved for grid connection, and an unapproved system that does not meet PEA criteria while still being connected to the grid.

If your system can feed power into the public grid, then PEA has every reason to demand approved equipment, inspection, and documentation. That is not only bureaucracy. It is about safety, responsibility, and protecting the grid.

Off-grid is one thing. But once your system is connected to the grid, it is no longer only your private system.

3 minutes ago, Hummin said:

It is also about the difference between a legal solar system approved for grid connection, and an unapproved system that does not meet PEA criteria while still being connected to the grid.

If your system can feed power into the public grid, then PEA has every reason to demand approved equipment, inspection, and documentation. That is not only bureaucracy. It is about safety, responsibility, and protecting the grid.

Off-grid is one thing. But once your system is connected to the grid, it is no longer only your private system.

You're absolutely correct .

I got a lot of information and advice from web boards etc. ASEAN Now included.

It was clear that the way forward was to do it correctly and professionally.

Everything fully registered, fully certified, and fully approved.

It's clear from this discussion which web board members didn't do theirs properly. 🙂

6 minutes ago, Hummin said:

Even more unpopular my claim is

This is not only about ROI or freedom to change your own system.

It is also about the difference between a legal solar system approved for grid connection, and an unapproved system that does not meet PEA criteria while still being connected to the grid.

If your system can feed power into the public grid, then PEA has every reason to demand approved equipment, inspection, and documentation. That is not only bureaucracy. It is about safety, responsibility, and protecting the grid.

Off-grid is one thing. But once your system is connected to the grid, it is no longer only your private system.

If you update your system, per the contract, you need a new inspection. Basically everyone updates their system. If they start enforcing the laws which I doubt but maybe, you always can just go off grid. I would buy a backup inverter and be good to go. I would rather not but an easy fix. Alternatively I could also go buy an approved inverter and go through the steps to get certified.

Too many easy fixes and I agree with you - PEA has every right to manage how we use their grid. My inverter like almost all new inverters have anti-islanding so it will shut down exports if the grid shuts down. Still agree that PEA has the right to inspect of you are on the grid.

13 minutes ago, Packer said:

You're absolutely correct .

I got a lot of information and advice from web boards etc. ASEAN Now included.

It was clear that the way forward was to do it correctly and professionally.

Everything fully registered, fully certified, and fully approved.

It's clear from this discussion which web board members didn't do theirs properly. 🙂

Again - you obviously won't share your info and most if not all the nice people that helped you don't have approved PEA systems.

Come on. Brag and show us your system specs and cost :) I think I know why you won't. Maybe you posted in another thread...

6 minutes ago, atpeace said:

Again - you obviously won't share your info and most if not all the nice people that helped you don't have approved PEA systems.

Come on. Brag and show us your system specs and cost :) I think I know why you won't. Maybe you posted in another thread...

He probably paid 400kbht for a 100kbht install.

You can't fix stupid!

7 minutes ago, atpeace said:

most if not all the nice people that helped you don't have approved PEA systems.

"Learning what not to do, from other's mistakes, is as important as learning what to do, from other's successes."

Packer.

did i got this one wrong?

to be part of the program of 2026, only a max 5 kwp on-grid solar system without a battery is allowed per residential electricity meter ... ?

Edited July 4Jul 4 by motdaeng

2 minutes ago, BritManToo said:

He probably paid 400kbht for a 100kbht install.

You can't fix stupid!

He is pompous fool. He knows very well without completely making up numbers that his system will never pay for itself. He does have his PEA certification that I bet he hangs at eye level across from the toilet.

15 minutes ago, atpeace said:

If you update your system, per the contract, you need a new inspection. Basically everyone updates their system. If they start enforcing the laws which I doubt but maybe, you always can just go off grid. I would buy a backup inverter and be good to go. I would rather not but an easy fix. Alternatively I could also go buy an approved inverter and go through the steps to get certified.

Too many easy fixes and I agree with you - PEA has every right to manage how we use their grid. My inverter like almost all new inverters have anti-islanding so it will shut down exports if the grid shuts down. Still agree that PEA has the right to inspect of you are on the grid.

Another valid point is Home Property insurance, where you need receipts and a properly documented installation.

5 minutes ago, Packer said:

"Learning what not to do, from other's mistakes, is as important as learning what to do, from other's successes."

Packer.

So now you are stating that the nice people that helped you and who have functioning solar system ( they have all supplied data about their systems) are not as intelligent as yourself. Interesting but your manner of communication and avoidance of supplying data tells a different story.

Here is what I think. You are leading a pathetic life here as you did back home. You were grouch back home and you are a sad lonely grouch here.

3 minutes ago, Hummin said:

Another valid point is Home Property insurance, where you need receipts and a properly documented installation.

I didn't know that. I love my home but if it was destroyed I would just build another without prop insurance :) I get where you are coming from though and I do like the pics of your home. Beautiful views and big windows - very cool!

8 minutes ago, atpeace said:

He is pompous fool.

3 minutes ago, atpeace said:

You are leading a pathetic life here as you did back home. You were grouch back home and you are a sad lonely grouch here.

Sell the Kw your anger produces at 2.2 thb and you could afford at proper, certified system. 🙂

9 minutes ago, BritManToo said:

He probably paid 400kbht for a 100kbht install.

You can't fix stupid!

Using a proper company with engineer design, you cannot call that stupid, BritMan. I have personally seen homemade systems, and for some reason they often keep changing components, rebuilding, and adjusting things. I have seen your updates with the same.

Brand names matter, factory warranty matters, sustainability and lifespan matter, and documentation matters too.

2 minutes ago, Packer said:

Sell the Kw your anger produces at 2.2 thb and you could afford at proper, certified system. 🙂

2 minutes ago, Packer said:

Sell the Kw your anger produces at 2.2 thb and you could afford at proper, certified system. 🙂

Please kindly provide your system specs. It would be much appreciated and I apologize for upsetting you :) Cheers

7 minutes ago, atpeace said:

I didn't know that. I love my home but if it was destroyed I would just build another without prop insurance :) I get where you are coming from though and I do like the pics of your home. Beautiful views and big windows - very cool!

Still, it is a home built by local farmers and insured within a 3 million baht plan, including the solar system. So it is no farang mansion. My gym, solar system, inventory AC etc, comes close to half of the total cost actually.

2 minutes ago, Hummin said:

Using a proper company with engineer design, you cannot call that stupid, BritMan. I have personally seen homemade systems, and for some reason they often keep changing components, rebuilding, and adjusting things. I have seen your updates with the same.

Brand names matter, factory warranty matters, sustainability and lifespan matter, and documentation matters too.

That would also go for the most expensive professional systems as can be verified through reading through some of the popular threads. The costs to fix are astronomical in many cases. Some people on these forums have had fixes that cost as much as their original system when it was professionally installed. Large sections of panels not working, replacement of expensive ESS, inverters, complete replacement of all panels....

I think there is a middle ground where you can still expect a ROI but even then luck is needed :) IMO, just have fun with it and don't blow your budget. Some have loads of money so they have different perspectives.

2 hours ago, BritManToo said:

have a degree in Electrical and Electronic engineering,

I got the same from Sheffield University in 1968/9.

The idea of getting electricity from the sun shining down on my rrof, and going into my car was not thought of.

Computers were still experimenting with glass-encased reed switches!

Edited July 4Jul 4 by wil iam not

2 minutes ago, Hummin said:

Still, it is a home built by local farmers and insured within a 3 million baht plan, including the solar system. So it is no farang mansion. My gym, solar system, inventory AC etc, comes close to half of the total cost actually.

That is nice and amazing what you can do here for 3m. My home is only a little over 1m and it has everything I need. My last home was over 4m and also wasn't a mansion.

I have a really nice view and the Mekong is across the street but I miss having more expansive views like you have that I had prior to moving here.

4 minutes ago, atpeace said:

That would also go for the most expensive professional systems as can be verified through reading through some of the popular threads. The costs to fix are astronomical in many cases. Some people on these forums have had fixes that cost as much as their original system when it was professionally installed. Large sections of panels not working, replacement of expensive ESS, inverters, complete replacement of all panels....

I think there is a middle ground where you can still expect a ROI but even then luck is needed :) IMO, just have fun with it and don't blow your budget. Some have loads of money so they have different perspectives.

I know we could have paid half the amount, maybe even less, if we had used certain installers we would never see again after installation.

With our installer, who has a great reputation for after-service and follow-up, we know they will not just run away. And the factory warranty is valid, with or without their company.

Panels have a lifespan of around 30 years with 12 years warranty. The batteries are rated up to 10,000 cycles, and Sigenergy gives 10 years warranty on the battery and inverter/controller.

Brand names and choice of installer matter, but I agree, it is hard to know for sure. That is what I actually paid for: a competent installer and a brand with a good reputation, proper documentation, warranty, after-service, and the newest technology.

29 minutes ago, motdaeng said:

did i got this one wrong?

to be part of the program of 2026, only a max 5 kwp on-grid solar system without a battery is allowed per residential electricity meter ... ?

That is at any given moment. It is to protect the grid from too much power being exported.

Most homes with solar probably are using 3-4kWh during the day (home and charge ESS) so if they have 10KWh of panels like I do they export 2-7kWh a day. Yep - not worth it. If you upgrade your system and other have added solar in your neighborhood you need a new contract and might even lose the ability to export. Messy.....

5 minutes ago, Hummin said:

I know we could have paid half the amount, maybe even less, if we had used certain installers we would never see again after installation.

With our installer, who has a great reputation for after-service and follow-up, we know they will not just run away. And the factory warranty is valid, with or without their company.

Panels have a lifespan of around 30 years with 12 years warranty. The batteries are rated up to 10,000 cycles, and Sigenergy gives 10 years warranty on the battery and inverter/controller.

Brand names and choice of installer matter, but I agree, it is hard to know for sure. That is what I actually paid for: a competent installer and a brand with a good reputation, proper documentation, warranty, after-service, and the newest technology.

Your plan is good. I'm different. I like to tinker and save money and I usually don't know as much as i should about what I'm tinkering with. As you mentioned in an earlier post, that in the end can be more expensive! I have made this error countless times over the years :) In the end, I have loads of time and enough money so whatever :)

56 minutes ago, atpeace said:

Maybe you posted in another thread...

36 minutes ago, atpeace said:

Please kindly provide your system specs.

The obsessive stalking search was unproductive eh. 🙂

24 minutes ago, wil iam not said:

I got the same from Sheffield University in 1968/9.

The idea of getting electricity from the sun shining down on my rrof, and going into my car was not thought of.

Computers were still experimenting with glass-encased reed switches!

Completely true. 🙂

2 minutes ago, Packer said:

The obsessive stalking search was unproductive eh. 🙂

Do you think I would waste my time with someone as inconsequential as yourself. You really think you are important - amazing...

At this point, it is more than obvious that you overpaid for your system and now are desperately grasping at solutions to recoup a portion of your investment. Just put your tail between your legs and scurry away. It is OK, you have your PEA certification and you can frame it up or wipe your butt with it. Up to you :)

Edited July 4Jul 4 by atpeace

2 minutes ago, atpeace said:

you have your PEA certification

Of course. 🙂

1 hour ago, Packer said:

Service cost of the official check inc. 7% Vat (in Kw) : 972

...

Time to supply 972Kw to the grid: A single digit in months.

could you please explain your numbers? they don't make any sense to me ...

4 hours ago, atpeace said:

Most people upgrading their systems mid-stream are doing it purely for self-consumption—adding a larger hybrid inverter and battery storage to cut their own bill. If you run a high-quality system with a smart zero-export limiter, you keep total control over your hardware choices and avoid the PEA inspection loop entirely.

You answered the question that was forming as I read your post.

2 hours ago, Packer said:

Yes.

Professionally installed system that obviously meets all the requirements already, as it was installed by professionals using certified approved systems, officially registered, and requires no additional expansions or adjustments within the next 10 years.

Service cost of the official check inc. 7% Vat (in Kw) : 972

Contract duration: 10 years (triple digits in months)

Time to supply 972Kw to the grid: A single digit in months.

🙂

I don't understand your 972 kW figure. You're paid for the quantity of energy delivered (usually measured in kWh). 972 kW means 972,000 joules per second. This is an energy rate, not a quantity. How many kWh do you export to the grid per month?