Solar power, can it be done DIY?

[Sophon]

16 minutes ago, Muhendis said:

Do you have surge arrestors on you incomer from PEA?

If you do. 

Are they located immediately after the incoming power breaker/isolator?

Yes, you can see them on the picture. It goes like incoming breaker => power meter => surge arrestor. 

[Muhendis]

12 minutes ago, Sophon said:

Yes, you can see them on the picture. It goes like incoming breaker => power meter => surge arrestor. 

Is the incoming surge arrestor in good health and did the incoming breaker trip?

[Sophon]

14 minutes ago, Muhendis said:

Is the incoming surge arrestor in good health and did the incoming breaker trip?

Not sure if the incoming breaker tripped, I was concentrating on the inverter which was blowing smoke. The battery and PV panel breakers did trip. The surge arrestors looks OK, but other than visually, I don't know how to check.

Edited June 18, 2023 by Sophon

[Muhendis]

You have almost certainly had an EMP event from a nearby lightning strike. It seems your surge arrestors in the solar panel incoming circuit did not trip the DC isolator quick enough and the pulse(s) were big enough to bypass the built-in surge arrestor components inside the inverter.

The PEA meter damage also indicates a surge. Probably the same lightning EMP.

22 minutes ago, Sophon said:

I was concentrating on the inverter which was blowing smoke.

Yeah indeed as I would also. 

 

Sometimes natural events can be bigger and stronger than we can anticipate. 

The only thing I can think of to prepare for the next time is to put some high speed fuses in the solar panel feed. This should ensure that when the surge arrestor conducts, the surge current will instantly cause the fuses to blow and break the connection before damage is done. Maybe the DC MCB was a bit too slow.

Edited June 18, 2023 by Muhendis

[Muhendis]

17 minutes ago, Muhendis said:

You have almost certainly had an EMP event from a nearby lightning strike. It seems your surge arrestors in the solar panel incoming circuit did not trip the DC isolator quick enough and the pulse(s) were big enough to bypass the built-in surge arrestor components inside the inverter.

The PEA meter damage also indicates a surge. Probably the same lightning EMP.

Yeah indeed as I would also. 

 

Sometimes natural events can be bigger and stronger than we can anticipate. 

The only thing I can think of to prepare for the next time is to put some high speed fuses in the solar panel feed. This should ensure that when the surge arrestor conducts, the surge current will instantly cause the fuses to blow and break the connection before damage is done. Maybe the DC MCB was a bit too slow.

Something like this.

https://shopee.co.th/ฟิวส์พลังงานแสงอาทิตย์-PV-DC-1000V-PV-Fuses-10A-15A-30A-แรงดันสูง-ป้องกันระบบสุริยะ-ไม่ใช่ชุดเดียว-i.516543065.15598785952?sp_atk=258598d3-0d81-4e68-841a-ec4381c991a9&xptdk=258598d3-0d81-4e68-841a-ec4381c991a9

[Sophon]

40 minutes ago, Muhendis said:

You have almost certainly had an EMP event from a nearby lightning strike. It seems your surge arrestors in the solar panel incoming circuit did not trip the DC isolator quick enough and the pulse(s) were big enough to bypass the built-in surge arrestor components inside the inverter.

The PEA meter damage also indicates a surge. Probably the same lightning EMP.

Yeah indeed as I would also. 

 

Sometimes natural events can be bigger and stronger than we can anticipate. 

The only thing I can think of to prepare for the next time is to put some high speed fuses in the solar panel feed. This should ensure that when the surge arrestor conducts, the surge current will instantly cause the fuses to blow and break the connection before damage is done. Maybe the DC MCB was a bit too slow.

I do have fuses like this (only 25A) on the leads for the PV panels, and they didn't blow.

As mentioned, there was no lightning at the time, but perhaps we had a hit sometime during the night before that did damage, and that damage eventually caused the inverter to fry.

[Muhendis]

36 minutes ago, Sophon said:

I do have fuses like this (only 25A) on the leads for the PV panels, and they didn't blow.

As mentioned, there was no lightning at the time, but perhaps we had a hit sometime during the night before that did damage, and that damage eventually caused the inverter to fry.

 

Your PEA meter and that of your neighbour both became u/s at the same time so something happened on the PEA line.

What is the distance from the PEA meter to your PEA input surge protector?

What is the distance from your PV fuse to your PV surge protector?

 

[Sophon]

5 minutes ago, Muhendis said:

Your PEA meter and that of your neighbour both became u/s at the same time so something happened on the PEA line.

What is the distance from the PEA meter to your PEA input surge protector?

What is the distance from your PV fuse to your PV surge protector?

 

What is the distance from the PEA meter to your PEA input surge protector?

As the crow flies, 4 meters. Following the wires 10-12 meters.

 

What is the distance from your PV fuse to your PV surge protector?

Again approx. 4 meters as the crow flies, 6-7 meters following the wires.

[Muhendis]

33 minutes ago, Sophon said:

What is the distance from the PEA meter to your PEA input surge protector?

As the crow flies, 4 meters. Following the wires 10-12 meters.

 

What is the distance from your PV fuse to your PV surge protector?

Again approx. 4 meters as the crow flies, 6-7 meters following the wires.

Another question or two

What it the maximum open circuit voltage of the panel array?

What is the maximum solar input of the inverter?

[Sophon]

5 minutes ago, Muhendis said:

Another question or two

What it the maximum open circuit voltage of the panel array?

What is the maximum solar input of the inverter?

The panels are in two strings of 7 panels, and the panels have a Voc rating of 47.1V, so a theoretical maximum of 329.7V. The inverter allowed a maximum of 500V from the PV panels.

[Muhendis]

17 minutes ago, Sophon said:

The panels are in two strings of 7 panels, and the panels have a Voc rating of 47.1V, so a theoretical maximum of 329.7V. The inverter allowed a maximum of 500V from the PV panels.

OK so looking at the suppressors they each have a Uc (continuous working voltage) of 800v which effectively means they will only suppress voltages over 800v

I suspect that is higher than the components of your inverter would be happy with.

The suppressors need to be somewhere in the range of 329.7v minimum to 500v maximum.

It would be nice if you could find one with Uc of 450v

https://shopee.co.th/Suntree-เสิร์จกันฟ้าผ่า-SUP2H-PV-DC-SPD-500V-2P-20-40KA-กันฟ้าผ่า-อุปกรณ์ป้องกันฟ้าผ่า-Surge-Protection-ซันทรี-ธันไฟฟ้า-SSS-i.303694660.2960555499?sp_atk=0289ebcc-e17f-4047-acce-39f10d304d1b&xptdk=0289ebcc-e17f-4047-acce-39f10d304d1b

[Sophon]

Quick update.

 

After being frozen for two weeks, our PEA meter started running again today. PEA didn't change the meter, as a matter of fact I don't think they did anything as our dogs would have alerted us if they came by and started working on the meter, which is only a few meters from our land. So the meter must somehow have come unstuck on it own.

 

The neighbor's meter still isn't spinning though.

[Tubulat]

On 6/18/2023 at 1:26 PM, JBChiangRai said:

I don't see a data cable between your inverters, required to make them synchronise.

 

Also, is the cable run from each inverter to battery, the same length and size?

There is a data cable between the 2 inverters, the lenght of the cables from each inverter to the battery packs are about the same, both are 35 mm sq.

BTW did you get also a message about a new inverter from Must?

[JBChiangRai]

27 minutes ago, Tubulat said:

 

BTW did you get also a message about a new inverter from Must?

 

I get emails from them occasionally, I don't specifically remember one inverter, I tend to look at all of them.

 

I think I have 3 of the same inverters in your photo (5.5Kw Hybrid).  I couldn't get them to export any decent amount to PEA and when they were working, they were incredibly noisy so I added 3 grid-tied 6Kw MUST inverters and moved the PV onto them, now I use the Hybrid inverters purely as whole house UPS.

 

I bought direct from MUST in China, shipped Thailand Special Line so no duty/VAT payable, came out at half the price of Lazada delivered to my door.

 

Are your battery packs connected in parallel as one big pack? The inverters will fail if there is a mismatch in battery voltages, it's why they tell you to keep the cables the same length.

Edited July 17, 2023 by JBChiangRai
add info

[Tubulat]

1 minute ago, JBChiangRai said:

I get emails from them occasionally, I don't specifically remember one inverter, I tend to look at all of them.

 

I think I have 3 of the same inverters in your photo (5.5Kw Hybrid).  I couldn't get them to export any decent amount to PEA and when they were working, they were incredibly noisy so I added 3 grid-tied 6Kw MUST inverters and moved the PV onto them, now I use the Hybrid inverters purely as whole house UPS.

 

I bought direct from MUST in China, shipped Thailand Special Line so no duty/VAT payable, came out at half the price of Lazada delivered to my door.

Okay, so despite all the problems, you still chose 'Must' again.
I remember you complaining about the noise from the fans, they do that to me too but they are hang outside so it doesn't bother me.
But unlike the problems you had regarding feeding them back to the grid, which I don't want, on mine they stay connected to the grid even though the batteries are full, so each time I have to manually disconnect them from the grid.
This complaint and the other that it is impossible to get info via an app on my phone I submitted to Must after I received an email regarding the new inverter, with a lot of sorries but no answer for a solution.

 

[JBChiangRai]

15 minutes ago, Tubulat said:

Okay, so despite all the problems, you still chose 'Must' again.
I remember you complaining about the noise from the fans, they do that to me too but they are hang outside so it doesn't bother me.
But unlike the problems you had regarding feeding them back to the grid, which I don't want, on mine they stay connected to the grid even though the batteries are full, so each time I have to manually disconnect them from the grid.
This complaint and the other that it is impossible to get info via an app on my phone I submitted to Must after I received an email regarding the new inverter, with a lot of sorries but no answer for a solution.

 

MUST's after sales service is practically zero.  I have installed their grid-tied inverters before in my previous house, and they just work out the box with no configuration needed.

 

I can also live with noise from the fans, I have a small room that is permanently air conditioned that serves 3 functions, inverters/batteries, computer servers, and wine cellar.  It is opposite the maid's room so she would be the one to get the noise and I wouldn't be happy about that, she's like family.

 

I cleaned the filters on the Hybrid inverters after 18 months, they were filthy and they are only ever doing anything during a power cut.

 

Do you have the WiFi adaptors to go with the inverters?  I did have them and might be able to find a couple if you need them.

[Tubulat]

3 hours ago, JBChiangRai said:

MUST's after sales service is practically zero.  I have installed their grid-tied inverters before in my previous house, and they just work out the box with no configuration needed.

 

I can also live with noise from the fans, I have a small room that is permanently air conditioned that serves 3 functions, inverters/batteries, computer servers, and wine cellar.  It is opposite the maid's room so she would be the one to get the noise and I wouldn't be happy about that, she's like family.

 

I cleaned the filters on the Hybrid inverters after 18 months, they were filthy and they are only ever doing anything during a power cut.

 

Do you have the WiFi adaptors to go with the inverters?  I did have them and might be able to find a couple if you need them.

Thanks for your offer but I have 2 of them have tried many times, also with the help of the supplier, but yes that is a Chinese, so that does not make any progress and have long ago given up the courage.

But is is not important, everyday I take a look to the installation, check the batteries, and that's it.

Also filters check daily, and clean them when necessary.

[Sophon]

It's now been 7 months since my system went online. The last 3-4 months the weather have been terrible, many days with whole day thick cloud cover and very little solar production. Some days I only managed to produce enough to cover the day time usage, with next to nothing going into the batteries.

 

This is the monthly production since going live:

 

So despite the bad weather over the last 4 months my system has covered 81.3% of our electricity usage. It's reasonable to project the weather to be much better over the next 5 months, so over the first year I expect my system to have produced 85-90% of our usage. So with limited potential further savings, upscaling my system would make absolutely no financial sense.

 

With that being said, I have just ordered 10 more 390w panels. My primary goal when deciding to install solar panels was never about saving money, but rather not having to rely on PEA for our electricity. With my current system there are too many days when we don't have enough production to cover our needs causing the batteries run out during the night/morning. If that coincides with the PEA having a power outage then I am back where I started. I also have to plan carefully when to charge the EV, to make sure I still have enough in the house battery to tide us over until I can recharge them the next day. And on cloudy days I have to rely on PEA when charging the EV.

 

Buying more battery storage makes even less financial sense than buying more solar panels, but despite that I will probably still add another 14kWh later this year. I haven't decided yet, but I am leaning in that direction.

[Sophon]

Something I would like the forum members opinion on.

 

I live in Lamphun so in PEAs area, which I believe technically means that our supply should be 220V. In reality our supply varies between on the low end 222V and on the high end 233V, and generally it stays around 226V-228V. I can choose between 220V and 230V output in the inverter settings, and because the PEA supply is closer to 230V I have so far had the inverter set to 230V (which gives me 228V-229V at the house).

 

What would you do? Set the inverter to output 220V, which corresponds with the theoretical PEA supply voltage, or would you set it to 230V, which is closer to the actual voltage of our PEA supply?

 

 

[Crossy]

37 minutes ago, Sophon said:

What would you do? Set the inverter to output 220V, which corresponds with the theoretical PEA supply voltage, or would you set it to 230V, which is closer to the actual voltage of our PEA supply?

 

Do you have any appliances where it actually makes a visible difference?

 

Anything electronic will likely be constant-power so nothing changes.

Resistive heating will be marginally better at 230V.

 

[Sophon]

2 hours ago, Crossy said:

 

Do you have any appliances where it actually makes a visible difference?

 

Anything electronic will likely be constant-power so nothing changes.

Resistive heating will be marginally better at 230V.

 

 

No, we just have the normal stuff water pump, shower heater, kitchen appliances (rice cooker, electric pot, induction cooker). Nothing where the difference in voltage (at this scale) will make a difference. I have chosen 230V just because it's closer to our PEA supply not for any other reason, and is just curious what others would have done.

Edited November 3, 2023 by Sophon

[Sophon]

I ordered some box metal to build a ground mount for our extra solar panels. Notice the error message when Global House's system is unable to check the stock status 

[Sophon]

Finished the upgrade in January of an extra ground mount with ten 390W solar panels:

 

I also added another 14.3 kWh battery pack to our system:

 

The cells in the battery pack is rated at 280Ah, but if the test report from the seller is to believed they test out at a significantly higher capacity:

I managed to fully charge the battery packs and our EV before we hit a dreary patch of four days in a row with next to no sunshine. Before the upgrade such weather would have had us relying on PEA for power, but with the new panels we had no trouble covering our daily consumption (although i wasn't able to charge the EV again until yesterday when the sun was back).

 

[ThaiFig]

Inspiring thread, I got a number of good ideas from it that I will shamelessly copy.  I am presently collecting the final pieces for my own solar installation, an 8 kilowatt solar doghouse. If anyone is interested in seeing another work in progress, I could start a new thread to document the project as it advances.  I would welcome concrete suggestions for alternative approaches or things I'm overlooking  as I go forward, or alternative suppliers other than Shoppee and Lazada.  The goal is to eventually go to near 100% off grid, to avoid erratic power surges, short electricity flow interruptions, and future price increases in energy costs, in addition to being able to run the aircon 24/7 without breaking the bank. 

[ThaiFig]

On 2/1/2024 at 11:54 AM, Sophon said:

Finished the upgrade in January of an extra ground mount with ten 390W solar panels:

 

I also added another 14.3 kWh battery pack to our system:

 

The cells in the battery pack is rated at 280Ah, but if the test report from the seller is to believed they test out at a significantly higher capacity:

I managed to fully charge the battery packs and our EV before we hit a dreary patch of four days in a row with next to no sunshine. Before the upgrade such weather would have had us relying on PEA for power, but with the new panels we had no trouble covering our daily consumption (although i wasn't able to charge the EV again until yesterday when the sun was back).

 

48 volt lifepo4 pack?  How much does it cost? Where did you get it? What's the model and brand?  Enquiring minds want to know 😀 I'm looking into storage options myself.

 

[Crossy]

23 minutes ago, ThaiFig said:

Inspiring thread, I got a number of good ideas from it that I will shamelessly copy.  I am presently collecting the final pieces for my own solar installation, an 8 kilowatt solar doghouse. If anyone is interested in seeing another work in progress, I could start a new thread to document the project as it advances.  I would welcome concrete suggestions for alternative approaches or things I'm overlooking  as I go forward, or alternative suppliers other than Shoppee and Lazada.  The goal is to eventually go to near 100% off grid, to avoid erratic power surges, short electricity flow interruptions, and future price increases in energy costs, in addition to being able to run the aircon 24/7 without breaking the bank. 

 

Please do start a construction thread, the more up to date detail we have the better.

 

[Sophon]

1 hour ago, ThaiFig said:

48 volt lifepo4 pack?  How much does it cost? Where did you get it? What's the model and brand?  Enquiring minds want to know 😀 I'm looking into storage options myself.

 

 

Total was USD 2,738 all included, but the price has probably gone down somewhat since then
https://www.alibaba.com/product-detail/14KW-48V-51-2V-280AH-Pre_1600894719244.html?spm=a2756.order-detail-ta-ta-b.0.0.7ec62fc2NeuxSJ

[ThaiFig]

6 minutes ago, Sophon said:

 

Total was USD 2,738 all included, but the price has probably gone down somewhat since then
https://www.alibaba.com/product-detail/14KW-48V-51-2V-280AH-Pre_1600894719244.html?spm=a2756.order-detail-ta-ta-b.0.0.7ec62fc2NeuxSJ

Thanks 😊

[Muhendis]

3 hours ago, ThaiFig said:

I'm looking into storage options myself.

LiFePO4's are not the only storage solution.

Have a look at lead carbon batteries. 

They have similar lifespan to LiFePO4

They are significantly cheaper.

They are more robust and don't need any special electronics to keep them safe.

 

The following might help to understand better how they work.

https://www.kijo-battery.com/lead-carbon-battery.html#:~:text=Lead-carbon battery is a,advantages of lead-acid batteries.

 

I have 12 x 250Ah gel type lead carbon batteries and I am very pleased with them.

I got mine from a Chinese company not the one in the link

Edited March 5 by Muhendis

[ThaiFig]

Interesting. Victron apparently has some as well.  Here's what they had to say about them: