There's always the exception to the slapped wrist: -

I am almost completely off grid with my solar system.

I can connect to PEA via my ATS when there is a need which is usually five or six times a year.

I used to have a grid connected set of three inverters in parallel which worked fine until there was a very close double lightning strike.

The first strike stressed the surge arresters and the second, which came one second later, took out two of the inverters.

This was about ten years or so ago and I'm sure lightning protection is now better understood.

Fitting an ATS and being mostly isolated from PEA suits me just fine for lightning security reasons alone.

As for running the meter backwards, I wouldn't touch it with a bargepole.

I have little interest in recouping the costs of my electric solar installation because initially and for the first seven years, I was on temporary supply at 8 Baht / unit.

It was during the first of those seven years I installed my initial solar system so from then on I had free energy.

Just some info for anyone looking at getting a solar sytem.

So i have not bought an additional battery yet. (16kw Deye battery installed)

We have just added 4 more a/c units
Now we have a total of 6 a/c
If we run them all and the pool pump we are not able to charge the 15kw battery much maybe only 30-40% charge
We now run 2-3 a/c+ pool pump and can now charge the battery to 100% by around 1pm then we can put on the other a/c's on flat out until around 4.30pm
If we get another battery i am not sure we will be able to charge it without getting more panels currently have 15k deye system
We are getting around 70-80 kw a day and using around 20 from the grid
Apart from adding more panels i am not sure getting a extra battery would be worthwhile
Bill just came 1600baht which is great as our previous house with just 2 a/c we were paying 4-4500 most months
Well worth the investment

Panels seem to be much easier to cost-justify than batteries

@kwak250 How many watts of panels do you have at present? How much room do you have for more panels?

Which inverter do you have?

You certainly need more panels before you need more battery, and panels are much more affordable.

But you may need another charge controller or even inverter to get the best out of them.

4 hours ago, Crossy said:

@kwak250 How many watts of panels do you have at present? How much room do you have for more panels?

Which inverter do you have?

You certainly need more panels before you need more battery, and panels are much more affordable.

But you may need another charge controller or even inverter to get the best out of them.

Hi crossy.

We have 22 x 705watt panels around 15500 watts

Inverter is a deye 16kw hybrid inverter

We use around 65-70 units between 8am-4.30pm

Battery only lasts to around 9pm each evening(15kwh)

20 units is used ifrom grid around

9pm-8.am

More panels would be good IF we had another battery but cant see we would need them otherwise as its only the 9pm-8am that we need 20units from

This is my understanding but might be wrong?

3 minutes ago, kwak250 said:

Hi crossy.

We have 22 x 705watt panels around 15500 watts

Inverter is a deye 16kw hybrid inverter

We use around 65-70 units between 8am-4.30pm

Battery only lasts to around 9pm each evening(15kwh)

20 units is used ifrom grid around

9pm-8.am

More panels would be good IF we had another battery but cant see we would need them otherwise as its only the 9pm-8am that we need 20units from

This is my understanding but might be wrong?

Do you have a time of Use (TOU) meter?

If not, you can likely cut you spend on night power.

19 minutes ago, Yellowtail said:

Do you have a time of Use (TOU) meter?

If not, you can likely cut you spend on night power.

Hi not that i know of its a new digital meter only just finished building the house in December last year

We can charge the 15kwh battery up quite quickly with pool pump and 2-3 ac's running (usually battery is full before 1pm)

We then put additional ac's on but if we had another battery maybe 15kwh it would probably be worth it.

Adding panels would certainly charge the battery's quicker and allow us to put all ac"s on before 1pm but having an extra battery and night would be more beneficial as the other ac's are in an area in the house we do not use much .

6 minutes ago, kwak250 said:

Hi not that i know of its a new digital meter only just finished building the house in December last year

We can charge the 15kwh battery up quite quickly with pool pump and 2-3 ac's running (usually battery is full before 1pm)

We then put additional ac's on but if we had another battery maybe 15kwh it would probably be worth it.

Adding panels would certainly charge the battery's quicker and allow us to put all ac"s on before 1pm but having an extra battery and night would be more beneficial as the other ac's are in an area in the house we do not use much .

If you have a TOU meter, your nighttime (22:00-09:00) rate is about 40% less than daytime rate, and it should show on your bill.

1 hour ago, Yellowtail said:

If you have a TOU meter, your nighttime (22:00-09:00) rate is about 40% less than daytime rate, and it should show on your bill.

I will have to check

Do.you need to apply for one of these?

11 hours ago, kwak250 said:

I will have to check

Do.you need to apply for one of these?

When you order the meter, you specify which type you want. I think there awas a B1,600 up-charge for the 3Ph TOU meter over the standard.

On 2/18/2026 at 2:08 PM, Crossy said:

OK confirmed that's a 16S pack.

There are loads on lazada that will work, some of better pedigree than others.

A mate bought one from LVtopsun recently and is most happy with the beast.

Have a look and post the one you are thinking about.

Not managed to get a battery yet as so busy with it being a new house but looks like prices have gone up?

trying to find a 32kw LVtopsun or similar but even a 16kw Deye is almost 100k?
Is this correct or am i looking in the wrong place/search
https://shopee.co.th/Deye-SE-F16-CMax-%E0%B9%81%E0%B8%9A%E0%B8%95%E0%B9%80%E0%B8%95%E0%B8%AD%E0%B8%A3%E0%B8%B5%E0%B9%88%E0%B8%A5%E0%B8%B4%E0%B9%80%E0%B8%98%E0%B8%B5%E0%B8%A2%E0%B8%A1314Ah-ESS-Solution-F16-C-Max-LiFePO4-16kWh-%E0%B9%80%E0%B8%AB%E0%B8%A1%E0%B8%B2%E0%B8%B0%E0%B8%AA%E0%B8%B3%E0%B8%AB%E0%B8%A3%E0%B8%B1%E0%B8%9A%E0%B8%A3%E0%B8%B0%E0%B8%9A%E0%B8%9A%E0%B9%82%E0%B8%8B%E0%B8%A5%E0%B8%B2%E0%B8%A3%E0%B9%8C%E0%B9%80%E0%B8%8B%E0%B8%A5%E0%B8%A5%E0%B9%8C-%E0%B8%A3%E0%B8%B1%E0%B8%9A%E0%B8%9B%E0%B8%A3%E0%B8%B0%E0%B8%81%E0%B8%B1%E0%B8%99-10-%E0%B8%9B%E0%B8%B5-i.132849870.47513778891?extraParams=%7B%22display_model_id%22%3A386189678228%2C%22model_selection_logic%22%3A3%7D

5 minutes ago, kwak250 said:

Not managed to get a battery yet as so busy with it being a new house but looks like prices have gone up?

trying to find a 32kw LVtopsun or similar but even a 16kw Deye is almost 100k?
Is this correct or am i looking in the wrong place/search
https://shopee.co.th/Deye-SE-F16-CMax-%E0%B9%81%E0%B8%9A%E0%B8%95%E0%B9%80%E0%B8%95%E0%B8%AD%E0%B8%A3%E0%B8%B5%E0%B9%88%E0%B8%A5%E0%B8%B4%E0%B9%80%E0%B8%98%E0%B8%B5%E0%B8%A2%E0%B8%A1314Ah-ESS-Solution-F16-C-Max-LiFePO4-16kWh-%E0%B9%80%E0%B8%AB%E0%B8%A1%E0%B8%B2%E0%B8%B0%E0%B8%AA%E0%B8%B3%E0%B8%AB%E0%B8%A3%E0%B8%B1%E0%B8%9A%E0%B8%A3%E0%B8%B0%E0%B8%9A%E0%B8%9A%E0%B9%82%E0%B8%8B%E0%B8%A5%E0%B8%B2%E0%B8%A3%E0%B9%8C%E0%B9%80%E0%B8%8B%E0%B8%A5%E0%B8%A5%E0%B9%8C-%E0%B8%A3%E0%B8%B1%E0%B8%9A%E0%B8%9B%E0%B8%A3%E0%B8%B0%E0%B8%81%E0%B8%B1%E0%B8%99-10-%E0%B8%9B%E0%B8%B5-i.132849870.47513778891?extraParams=%7B%22display_model_id%22%3A386189678228%2C%22model_selection_logic%22%3A3%7D

Batteries nearly doubled in price over the last year, along with solar panels.

16kwhr went from 37kbht to 50kbht

600w panels went from 1,700bht to 2,700bht.

13 minutes ago, BritManToo said:

Batteries nearly doubled in price over the last year, along with solar panels.

16kwhr went from 37kbht to 50kbht

600w panels went from 1,700bht to 2,700bht.

Ahh thanks now I see why I can't find a good deal

Might wait now and see if they drop again

On 3/26/2026 at 7:52 PM, Yellowtail said:

If you have a TOU meter, your nighttime (22:00-09:00) rate is about 40% less than daytime rate, and it should show on your bill.

My hunch is that savings aren't a real concern.

10 minutes ago, atpeace said:

My hunch is that savings aren't a real concern.

Savings are a concern

We have the TOU meter installed

A additional battery will be good but I can wait if they are crazy prices

Expect prices to continue rising, nothing gets cheaper...

Sadly, IMHO the aggressive "price-war" lows for both solar panels and LiFePO4 batteries seen globally through 2024 and 2025 have largely bottomed out, with 2026 marking a pivot toward stabilizing or increasing costs.

Solar Panels

• The Lows: Driven by massive factory overproduction and fierce competition in Asia, solar module prices plunged to historic depths over the last two years.

Prices have flattened or begun ticking upward. Manufacturers and government policies are actively working to curb unsustainable price wars, and changes to export incentives mean the era of continuously crashing spot-market panel prices has paused.

LiFePO4 (LFP) Batteries

• The Lows: Global battery pack prices hit record lows through 2025 (with stationary storage packs reaching remarkable lows near $70/kWh).

Prices have bottomed out. The market is facing upward pressure due to a rebound in critical raw material costs, surging energy storage demand from data centres and grids, and shifting tax rebate policies for exports out of China.

Second-life (OK, used) LiFePO4 (LFP) Batteries

• The market for second-life EV battery packs is expanding rapidly, with a projected compound annual growth rate (CAGR) between 25% and 42%, expected to reach a multi-billion dollar ecosystem by the mid-2030s.

The industry is pivoting from an ad-hoc DIY market into an industrial, automated supply chain.

China also cut some of the VAT rebates on solar system components, up to 15% on some. As always, it comes down to supply & demand.

11 hours ago, kwak250 said:

Savings are a concern

We have the TOU meter installed

A additional battery will be good but I can wait if they are crazy prices

Curious, if you want to share:
Total install cost (panels, current battery, inverter, misc)

PEA inspection and contract cost

TOU meter Cost

Any misc additions or maintenance costs

Do you have a screenshot of your monthly solar production?

I have contacts in town that would probably make the it easier to get approved but I can't get the numbers to make any financial sense. If I remember correctly PEA pays 2 baht per kWh and there is a daily limit. I can't find my spreadsheet where I had this info :(

I purchased a second battery in June 26. (the one on the right).

Same specs as the first one purchased in Dec 26.

LVTOPSUN 314 Ah, 51.2V, G3.

B 64950.

2 hours ago, carlyai said:

I purchased a second battery in June 26. (the one on the right).

Same specs as the first one purchased in Dec 26.

LVTOPSUN 314 Ah, 51.2V, G3.

B 64950.

That is so much cleaner than my 314 battery. Mine has been great for 2 years but it is basically an open box with 16 cells that are all in great shape and the pack always in balance. Mine cost 52k but if would have gladly paid 13k more for your battery. Have you had any issues with the battery?

3 minutes ago, atpeace said:

That is so much cleaner than my 314 battery. Mine has been great for 2 years but it is basically an open box with 16 cells that are all in great shape and the pack always in balance. Mine cost 52k but if would have gladly paid 13k more for your battery. Have you had any issues with the battery?

I had an issue with one of our 10kWh ESS (LVTOPSUN) and replaced under warranty. It was showing kWh draining, faster than being used.

Which confirmed, we really didn't need it. As it was rainy season, while the had it, when an extra ESS would come in handy. Rarely did the grid kick in overnight, and partly because we had it set to kick in @ 30% I think.

Edited August 5Aug 5 by KhunLA

2 hours ago, atpeace said:

If I remember correctly PEA pays 2 baht per kWh and there is a daily limit. I can't find my spreadsheet where I had this info :(

pea pays 2.2 bath per kWh, max 5 KW output, contract for 10 years ...

but in the small print they can reduce the max output if there is a problem with the grid ... :-(

Edited August 5Aug 5 by motdaeng

12 minutes ago, KhunLA said:

I had an issue with one of our 10kWh ESS (LVTOPSUN) and replaced under warranty. It was showing kWh draining, faster than being used.

Which confirmed, we really didn't need it. As it was rainy season, while the had it, when an extra ESS would come in handy. Rarely did the grid kick in overnight, and partly because we had it set to kick in @ 30% I think.

I had 1 day last year and 1 day so far this year when the grid kicked in. I put a barrier on the patio that hides my not so pretty set-up so I'm going to just abuse this battery for hopefully at least another 10 years. I go well below 30% half the year and always charge to 100% and float it there for a few hours.

I've bought into the LFP is extremely durable marketing! I have a battery (not the one powering my home) that is 6 years old that I use for lighting that goes to ~0% often and charged to 100% every day. I think the cells were used when I bought them on Lazada 6 years ago! It has been in the shade but in a hot area under a tin rough. It has had no issues so far.

3 minutes ago, atpeace said:

I had 1 day last year and 1 day so far this year when the grid kicked in. I put a barrier on the patio that hides my not so pretty set-up so I'm going to just abuse this battery for hopefully at least another 10 years. I go well below 30% half the year and always charge to 100% and float it there for a few hours.

I've bought into the LFP is extremely durable marketing! I have a battery (not the one powering my home) that is 6 years old that I use for lighting that goes to ~0% often and charged to 100% every day. I think the cells were used when I bought them on Lazada 6 years ago! It has been in the shade but in a hot area under a tin rough. It has had no issues so far.

We only got a 5 yr warranty, which is about the same time, we'll probably reach full ROI, so beyond that, electric will be truly free.

If one ESS craps out, and can't be fixed by me or a sparky, then I doubt if we would even replace it, as we really don't need it. Along with having 46 kWh sitting in the carport, if really needing a few kWh overnight

Edited August 5Aug 5 by KhunLA

17 minutes ago, motdaeng said:

pea pays 2.2 bath per kWh, max 5 KW output, contract for 10 years ...

but in the small print they can reduce the max output if there is a problem with the grid ... :-(

Why would anyone sign that contract???? You're tied into a tiny inverter for 10 years and in all likelihood the net export would be negative. You go through all the hoops and add at least 100k to the install only to still pay PEA monthly. It's as if PEA is telling us to bend over and take it.

Haven't been back to PEA after last time they said 20kW inverter too big, but you can limit the export to say 5kW (or 4.5kW to stop pushing over 5kW).

51 minutes ago, atpeace said:

That is so much cleaner than my 314 battery. Mine has been great for 2 years but it is basically an open box with 16 cells that are all in great shape and the pack always in balance. Mine cost 52k but if would have gladly paid 13k more for your battery. Have you had any issues with the battery?

No issues

Took a while to balance the two but I've got the inverter set to Lithium and it uses the BMS in a master slave setup, so they seem to charge and discharge at different rates.

I initially expected the batteries to show the same voltage as in parallel, but I suppose because they are under BMS control they charge and discharge how the BMS sees it. Nearly the same.

17 minutes ago, atpeace said:

Why would anyone sign that contract???? You're tied into a tiny inverter for 10 years and in all likelihood the net export would be negative. You go through all the hoops and add at least 100k to the install only to still pay PEA monthly. It's as if PEA is telling us to bend over and take it.

i looked into this carefully for myself and decided against it because of the bureaucracy, the restrictions on ground-mounted solar installations, and the small print ...

it was definitely worth considering (for our situation), because our average household electricity consumption is only around 6 kwh per day, plus roughly 200 kwh per month for our bev. we are also away from home for at least two months every year ...

a 5 kwp solar system (without a battery) would have been more than sufficient for our needs, and being able to sell the excess electricity back to the PEA at 2.2 baht per kwh would have made some financial sense (faster ROI) ...