Solar Panels

[Noris]

Hi all, the cost of solar panels in Thailand 250w Mono and Pure sine wave inverters to 220v

 

Cheers

[Crossy]

What size (Watts) inverter, are you looking for grid-tie, off-grid or hybrid?

 

250W panels are pretty small these days, you get better value with the larger panels.

 

Prices are a bit high at present, covid etc etc, a Sunergy 410W mono is 5,190 retail at Global House. Lazada suppliers are cheaper but often are nil-stock.

 

https://globalhouse.co.th/product/detail/2012110639336

 

[Noris]

On 7/23/2022 at 10:03 AM, Crossy said:

What size (Watts) inverter, are you looking for grid-tie, off-grid or hybrid?

 

250W panels are pretty small these days, you get better value with the larger panels.

 

Prices are a bit high at present, covid etc etc, a Sunergy 410W mono is 5,190 retail at Global House. Lazada suppliers are cheaper but often are nil-stock.

 

https://globalhouse.co.th/product/detail/2012110639336

 

Cheers

[Noris]

Just now, Noris said:

Wow not bad at the price 400w 5000B cheers

 

[Crossy]

Back in September last year I purchased 12 x 340W Jinyuan poly panels @ 2,890 Baht a pop, from Global House.

 

I should have bought more, prices are waaay up since then ???? 

[Noris]

54 minutes ago, Crossy said:

Back in September last year I purchased 12 x 340W Jinyuan poly panels @ 2,890 Baht a pop, from Global House.

 

I should have bought more, prices are waaay up since then ???? 

Wow, a good price yes the price has gone up a lot they also added a price hike in the UK mainly a tax.

[Encid]

On the subject of solar panels, I note the current prices from Global House are as follows:

 

 

 

My questions are related to the power rating (340W or 450W respectively).

 

I understand that this nameplate output wattage is under ideal (laboratory) circumstances, and does not take into account real life diminishing circumstances like dust, bird droppings, cloudy conditions, rain etc... so in sizing a system I would need to apply an efficiency rating... say an average of 2/3 output per day (say an 8 hour period).

 

Does this sound realistic?

 

What is the timeframe for the nameplate output wattage? 1 hour? 8 hours? 24 hours?

[Crossy]

For a very finger-in-the-air guesstimate (there are masses of variables):-

 

Panel rating x 0.8 x 5

(80% of panel rating over 5 hours)

 

Some days will be far better, some far worse.

[007 RED]

1 hour ago, Encid said:

My questions are related to the power rating (340W or 450W respectively).

 

I understand that this nameplate output wattage is under ideal (laboratory) circumstances, and does not take into account real life diminishing circumstances like dust, bird droppings, cloudy conditions, rain etc... so in sizing a system I would need to apply an efficiency rating... say an average of 2/3 output per day (say an 8 hour period).

 

Does this sound realistic?

 

What is the timeframe for the nameplate output wattage? 1 hour? 8 hours? 24 hours?

@Encid  You are 100% correct when you state that the output rating a solar panel (e.g. 340W or 450W) is determined under ideal (laboratory) conditions.  Basically this is a specific light source shining directly perpendicular onto a given area of photo cells within the panel.  Also, the temperature of the photo cells within the panel is maintained at a constant 25⁰C during the tests.

 

The biggest efficiency loss of solar panels is created by heat generated by the radiated light from the sun.  At mid-day, with the sun overhead, and no haze or clouds it is possible for the temperature of the panels get up to 70 or 80⁰C,.  For every 1⁰C above the laboratory test figure of 25⁰C, the efficiency of the panel will reduce by x%, where x% is the temperature co-efficient of the panel which can be between -0.2% to -0.5% depending upon type of panel and manufacturer.  Obviously the lower the the figure the better.

 

Other solar panel efficiency losses as you indicate can be caused by cloud, haze, dirt etc. which added to the loss cause by heat can be as much as 25%.  It is therefore, generally recommended to build in a potential loss of 25% when calculating the size of a system. 

 

For example, when I designed my small scale system I wanted it to produce a maximum of 7 units per day.   Based upon a 6 hour day, that means the panels need to produce 1.2 kWh.  The panels I choose were rated at 415W, so 4 x 415W should potentially give 1.660 kWh.  But because of a potential loss of 25% in reality they are more likely to produce my desired 1.2 kWh.

 

My small scale system has been running for almost a year now and the monitoring system shows an average daily production of between 6.5 and 7 kWh per day.

 

FYI.... 6 hours is normally used for sun calculations as there is very little power being generated by the panels between sun rise and mid-morning, and mid-afternoon and sun set.

 

I'm not sure what you mean by the timeframe for the nameplate output Wattage.  All I can assume is that if the panel is rated at say 450W, in theory (lab conditions) it should be capable of producing 450W with a given light source.  The 450W will only be produced so long as that specific light source is available to the photo cells of the panel. 

 

The graph below from my monitoring facility shows the output of my system during the day a few weeks ago and it clearly shows dips when the sun was obscured by heavy clouds and rain, hence loss of power.  On this particular day the system only managed to produce about 3.75 kWh.

I hope this helps.

 

[Encid]

9 minutes ago, 007 RED said:

I'm not sure what you mean by the timeframe for the nameplate output Wattage.

First of all thanks to both you and Crossy for your answers... all is clear to me now.

 

What I meant (and I should have elaborated more on it, but sometimes what is in your head doesn't quite make it to the written word) is the expected production from a fixed panel in a 24 hour period here in Thailand.

 

Both of you have given me similar answers... Crossy said panel rating x 0.8 x 5 (80% of panel rating over 5 hours),

and you said panel rating x 0.75 x 6 (75% of panel rating over 6 hours).

 

So if I plan to use 450W mono panels, on average I could expect daily production of between 1.8kW (using Crossy's formula) or 2.0kW (using your formula) per panel.

 

Correct?

 

I am also aware that there will be an approx 2% power degradation from the panels in their first year of operation, with an expected further degradation of 0.5% per year after that, so I am definitely an advocate of the "More is Better" theory.

[Crossy]

@Encid I don't think you are a million miles off there.

 

Like I said there are masses of variables, direction, angle, shading and of course the weather.

[Encid]

31 minutes ago, 007 RED said:

FYI.... 6 hours is normally used for sun calculations as there is very little power being generated by the panels between sun rise and mid-morning, and mid-afternoon and sun set.

What if one was to set up 3 strings of panels, say 30% facing east, 30% facing west, and 40% facing south.

 

Could that 6 hour production window be mitigated by such a setup?

[BritManToo]

48 minutes ago, 007 RED said:

FYI.... 6 hours is normally used for sun calculations as there is very little power being generated by the panels between sun rise and mid-morning, and mid-afternoon and sun set.

I get 1kW at 9am, rising to 2.2kW at midday.

[Crossy]

4 minutes ago, Encid said:

What if one was to set up 3 strings of panels, say 30% facing east, 30% facing west, and 40% facing south.

Could that 6 hour production window be mitigated by such a setup?

 

Sort of, spreading your panels like that will enable you to start generating earlier and finish later so extending your production day but your peak rate (around mid-day) will be lower because 60% of your panels are pointing the "wrong" way.

 

Thing is that "6 hours" doesn't mean your panels generate rated power for 6 hours it's just a way of getting an overall per day production without complex maths.

 

Our panels are producing power at 6.30AM and they finally give up at around 6PM, but sure as heck they're going nowhere near even 10% of rated power at those times. 

[007 RED]

2 hours ago, BritManToo said:

I get 1kW at 9am, rising to 2.2kW at midday.

I’m not surprised by your figures.  Sun rise is normally about 6am, so mid-morning is about 9am.  

 

If I remember correctly you have 9 x 330W panels which in theory are potentially capable of producing nearly 3kW under ideal conditions, so producing 1kW at 9am with good sunlight is fairly reasonable for a system of that size.

 

FYI....  My small scale system (4 x 415W panels =1.6kW) has also produced nearly 1kW at 9am on a few occasions when the sun has been really strong.  I’ve also seen the system peak at 1.5kW on a few occasions at mid-day.

[Encid]

I see that SolarShop in Surin are now selling 600W mono panels...

 

[Sophon]

On 8/7/2022 at 3:02 PM, Encid said:

What if one was to set up 3 strings of panels, say 30% facing east, 30% facing west, and 40% facing south.

 

Could that 6 hour production window be mitigated by such a setup?

I saw a video on YouTube from a guy who had done just that. The conclusion was that the East and West facing panels did produce a little more in the morning/evening than the south facing ones. however, because the sunlight is not strong at that time of day, the extra production early morning/late afternoon far from outweighed the reduced production from the panels during the middle portion of the day. He had better results when turning the panels from East and West to instead pointing South-East and South-West, but even so he didn't increase his total production, he just had a little more power early and late in the day (which was his goal).

 

This was a guy living somewhere in the U.S. with snowy winters, so the results could possibly be different in Thailand. but I think the overall principle stays the same. You get the best production from a stationary panel if it points due South.

[Encid]

Prices haven't changed much in the past 3 months...

 

 

 

[Encid]

On 11/4/2022 at 5:15 PM, Encid said:

Prices haven't changed much in the past 3 months...

 

 

 

 

One year later and prices have definitely changed... Global House no  longer stocks the 340W Poly model from Jinyuan, they now carry the 335W Poly model instead and it's 660 baht more expensive. 

 

I thought that prices were coming down... 

 

[SomchaiDIY]

53 minutes ago, Encid said:

One year later and prices have definitely changed... Global House no  longer stocks the 340W Poly model from Jinyuan, they now carry the 335W Poly model instead and it's 660 baht more expensive. 

 

I thought that prices were coming down... 

made collection some grade-a jinko 575watt mono type-n panel for friend

 

price 6366 baht / piece with tax 

 

11 baht / watt

 

same panel 1 year early 10.6 baht / watt

 

average for mono grade-a top brand now 11 baht / watt with tax

 

 

[KhunLA]

On 8/7/2022 at 3:02 PM, Encid said:

What if one was to set up 3 strings of panels, say 30% facing east, 30% facing west, and 40% facing south.

 

Could that 6 hour production window be mitigated by such a setup?

For our set up, we seem to have a 5ish hour peak time, I think.   Really hard to say, as we don't export any more, and only a few days during initial install that we did.

 

Which was also, krap weather, overcast & cloudy, as can see by the peaks & valleys in the graph.   BUT ... from near 1030, near  8kWh before going behind a cloud to 1530 hr, maybe, the inverter seemed to peak out at  8+ish kWh production.

 

18 panels @ 540w = 9.72kWh, minus whatever loss %.

2 strings of 9 panels each, due S & W

 

The only other day to get near those numbers, was actually last Monday, 3rd, both produced & consumed 44.8kWh, thanks to ACs & EV.

Edited April 9, 2023 by KhunLA

[TimeMachine]

I'm just about ready to purchase 6 panels. From what I can tell if you get 1 watt for 10 baht that's ok.

 

happy to use used panels too but people are asking same as new almost.

 

Looking to get this.

 

https://s.lazada.co.th/s.8Ptec

Can string the 6 panels in series. Not the most reliable brand but it's cheap. Hope to run a small inverter ac.

 

I'll wait to get to Udon thani Namsom where install location is, and see what the market is like there for solar panels.

 

 

 

 

[Muhendis]

A word of caution to all.

Check the power input rating of your inverter charge controller and, after taking into account the thermal derating factor, make sure your solar panel output does not exceed this. I differ a bit from others inasmuch I apply a derating of 10% which gives me a fair margin that I happen to be comfortable with.

 

The worst case conditions are:

1. New panels.

2. Spotlessly clean.

3. Sunlight perpendicular to the surface of the panels.

4. A goodly breeze to waft some of the heat away from the panels.

 

Another very important point is to make sure that your maximum panel string* voltage (Voc) does not  exceed the maximum permitted input voltage of the inverter charge controller. If it does, damage will occur and you will get some of @Crossy magic smoke.

 

Solar panels will loose 1%/annum of their rated output so after 20 years your output will be down to 80% of new.

There are some new techniques which improve on both the maximum output and longevity (25 years) but the regular panels are still at around 20% output which is to say that if 1kW of sunlight is shinning perpendicular to a 1 metre² panel, the panel will produce 200W of power.

 

* A string of panels is a number of panels connected in series so that their voltages are summed.

 

[TimeMachine]

39 minutes ago, Muhendis said:

A word of caution to all.

Check the power input rating of your inverter charge controller and, after taking into account the thermal derating factor, make sure your solar panel output does not exceed this. I differ a bit from others inasmuch I apply a derating of 10% which gives me a fair margin that I happen to be comfortable with.

 

The worst case conditions are:

1. New panels.

2. Spotlessly clean.

3. Sunlight perpendicular to the surface of the panels.

4. A goodly breeze to waft some of the heat away from the panels.

 

Another very important point is to make sure that your maximum panel string* voltage (Voc) does not  exceed the maximum permitted input voltage of the inverter charge controller. If it does, damage will occur and you will get some of @Crossy magic smoke.

 

Solar panels will loose 1%/annum of their rated output so after 20 years your output will be down to 80% of new.

There are some new techniques which improve on both the maximum output and longevity (25 years) but the regular panels are still at around 20% output which is to say that if 1kW of sunlight is shinning perpendicular to a 1 metre² panel, the panel will produce 200W of power.

 

* A string of panels is a number of panels connected in series so that their voltages are summed.

 

Thanks. The efficiency of stuff doesn't concern me because 20% less of zero is still zero. Sun is free..... For the moment. Taxes coming soon. They started in Oz already. 

[Crossy]

29 minutes ago, TimeMachine said:

Taxes coming soon. They started in Oz already. 

 

Are they actually taxing the sun?

 

I know the power companies are providing "free" off-grid systems to remote locations, then billing the power at normal network rates. This is because it's cheaper than maintaining the SWER lines that currently provide grid-power.

 

[Muhendis]

5 minutes ago, Crossy said:

 

Are they actually taxing the sun?

 

Probably coming to a village near you soon.

Governments and their big business pals are bad losers.

[Muhendis]

41 minutes ago, TimeMachine said:

Thanks. The efficiency of stuff doesn't concern me because 20% less of zero is still zero. Sun is free..... For the moment. Taxes coming soon. They started in Oz already. 

The efficiency has more to do with available space for mounting solar panels rather than the costs. 

You would need twice as much roof space for the same power output if the panels were only 10% 

[indyo]

4 hours ago, Muhendis said:

A word of caution to all.

Check the power input rating of your inverter charge controller and, after taking into account the thermal derating factor, make sure your solar panel output does not exceed this. I differ a bit from others inasmuch I apply a derating of 10% which gives me a fair margin that I happen to be comfortable with.

 

The worst case conditions are:

1. New panels.

2. Spotlessly clean.

3. Sunlight perpendicular to the surface of the panels.

4. A goodly breeze to waft some of the heat away from the panels.

 

Another very important point is to make sure that your maximum panel string* voltage (Voc) does not  exceed the maximum permitted input voltage of the inverter charge controller. If it does, damage will occur and you will get some of @Crossy magic smoke.

 

Solar panels will loose 1%/annum of their rated output so after 20 years your output will be down to 80% of new.

There are some new techniques which improve on both the maximum output and longevity (25 years) but the regular panels are still at around 20% output which is to say that if 1kW of sunlight is shinning perpendicular to a 1 metre² panel, the panel will produce 200W of power.

 

* A string of panels is a number of panels connected in series so that their voltages are summed.

 

too much panels in series on a metal roof doesn't look safe, how to keep the string voltage lower to be safe but enough higher to work with smaller diameter copper wire? (we are also speaking about DC voltage output from panels)

[Crossy]

1 hour ago, indyo said:

too much panels in series on a metal roof doesn't look safe, how to keep the string voltage lower to be safe but enough higher to work with smaller diameter copper wire? (we are also speaking about DC voltage output from panels)

 

Lower voltage will need THICKER wire for the same power (higher current). You need to match the string voltage to the operating point of your MPPT controller without going over the maximum.

 

Why would high voltage be unsafe on a solidly grounded (via the building steel) metal roof?

 

Solar strings tend not to be ground-referenced anyway.

 

[Pink7]

1 hour ago, Crossy said:

Why would high voltage be unsafe on a solidly grounded (via the building steel) metal roof?

 

Solar strings tend not to be ground-referenced anyway.

 

Im mounting panels on a metal roof who is build on a steel construction In top of blocks and cement poles, with DIY solar rails of steel. I then got the idea to connect the steel roof or the garage steel construction to a Ground rod, will that work?

 

Pink