Solar Power

[sfokevin]

Since you have no background in this I would suggest you start out with a basic system to learn and then scale up from there...

 

Look a a grid tied inverter like this...

https://www.lazada.co.th/products/2000-grid-tie-inverter-dc-45-90-v-pv-ac190v-260v-300w-6-1-i317922520-s600542057.html?spm=a2o4m.searchlist.list.8.71932772HWnTFW&search=1

 

Buy yourself 6 330w panels @ ~4K baht a piece...

 

With wiring and mounts and such your into it for under 50k...

 

https://youtu.be/utkH0S-6Da0

Edited August 17, 2019 by sfokevin

[sfokevin]

On 8/16/2019 at 5:03 PM, KhaoYai said:

The house will almost certainly be much the same as my current property and therefore have much the same power requirements

KhaoYai... What is your lowest and highest monthly PEA electric kw usage in a year?

 

You might look into a solar water preheater

Edited August 17, 2019 by sfokevin

[KhaoYai]

2 hours ago, sfokevin said:

KhaoYai... What is your lowest and highest monthly PEA electric kw usage in a year

Those figures could not really be used as at the moment I only visit for 2 weeks at a time. The water heater has a 200l tank and the initial heating of that will skew any power consumption figures I give - not that I can give them, I'm in the UK at the moment and the bills are at Khao Yai. All I can quote from here the billing amounts from my bank account which show that when I'm not there my bills are around 40-60 baht per month (2 fridges on) and when I am there for 2 weeks, the bill after that is between 800 and 1000 baht.

[tjo o tjim]

9 hours ago, sfokevin said:

You might look into a solar water preheater

Very smart move, and easy to do here.  Will likely give you 90% of the heat you need, and go for small instant units for the boost when you feel for it.

[Crossy]

7 hours ago, KhaoYai said:

and when I am there for 2 weeks, the bill after that is between 800 and 1000 baht.

 

A very quick and dirty calculation:-

 

2 weeks use = 1000 Baht = 71 Baht per day = about 18 units per day.

 

To cover that with a solar system you need to generate 18 units in about 5 hours of maxumim output = 3.6 units per hour.

 

So you're looking at about 4kW of solar.

 

Amorn Solar have a 3.6kW grid tie system for 77k Baht. Pretty sure this does NOT include installation or anciliary items so I would expect maybe 50% on top. Also I have no idea how up to date their site is.

 

https://www.amornsolar.com/product-page/set-on-grid-3-6k-solar-cell-kit-s-phase

 

 

[sfokevin]

Will a standard meter from PEA run backwards?

Does PEA allow it?

[Crossy]

4 minutes ago, sfokevin said:

Will a standard meter from PEA run backwards?

Does PEA allow it?

 

Yes

Sometimes

 

The official policy seems to vary from region to region, you are supposed to get permission from PEA for any grid-tie system and use their approved equipment but some areas just say no!

 

Best to ask your local office what paperwork is needed. You may need to use an approved contractor anyway ????

 

[sometimewoodworker]

45 minutes ago, Crossy said:

 

Yes

Sometimes

 

The official policy seems to vary from region to region, you are supposed to get permission from PEA for any grid-tie system and use their approved equipment but some areas just say no!

 

Best to ask your local office what paperwork is needed. You may need to use an approved contractor anyway ????

 

And doing it the legal way through the PEA is likely to add roughly 100% on to the system + installation charge as well as several months.

[sometimewoodworker]

55 minutes ago, sfokevin said:

Will a standard meter from PEA run backwards?

Does PEA allow it?

As crossy said 

 

But better to quietly link and make sure you never run the meter so far back as to give a negative reading.

[Crossy]

1 minute ago, sometimewoodworker said:

And doing it the legal way through the PEA is likely to add roughly 100% on to the system + installation charge as well as several months.

 

The experience of at least one poster seems to be that you install (get installed) the system and then get permission.

 

Seems arse-backwards to me. 

 

[Crossy]

4 minutes ago, sometimewoodworker said:

But better to quietly link and make sure you never run the meter so far back as to give a negative reading.

 

Yeah, I'm sorely tempted to just install a small system and hope the meter reader doesn't notice the disc going backwards.

[eisfeld]

51 minutes ago, Crossy said:

 

The experience of at least one poster seems to be that you install (get installed) the system and then get permission.

 

Seems arse-backwards to me. 

 

I can confirm that PEA in Chumpae told me this is how it works with the PEA solar rooftop program. I agree it's backwards. What if PEA says no? Tough luck.

[eisfeld]

1 hour ago, Crossy said:

The official policy seems to vary from region to region, you are supposed to get permission from PEA for any grid-tie system and use their approved equipment but some areas just say no!

Hm you can get permission from PEA to just spin the meter backwards? Did I understand you right? First time I hear this. I thought the only way is to apply for their rooftop program where they change the meter to one that counts two ways and then pays 1.8 THB per unit you fed in. But I haven't spoken to anyone who actually takes part in this program to know what meter they use and how it exactly works. The last thing I have red about the program was that there was not much demand and they missed their target by as much as 90% or some such ????

[eisfeld]

51 minutes ago, Crossy said:

 

Yeah, I'm sorely tempted to just install a small system and hope the meter reader doesn't notice the disc going backwards.

Or turn off the system during the two or three days that you know he comes. Depending on usage and generation that's a good idea anyways to make sure it doesn't read negative compared to the previous reading.

[Crossy]

You can (or at least could) indeed use net-metering (meter goes backwards when exporting) if you were not part of the My Solar Roof program.

 

The problem with the program seems to be the contract that one is expected to sign.

 

With net metering there's no contract (and of course no export rate). 

[eisfeld]

3 hours ago, Crossy said:

 

A very quick and dirty calculation:-

 

2 weeks use = 1000 Baht = 71 Baht per day = about 18 units per day.

 

To cover that with a solar system you need to generate 18 units in about 5 hours of maxumim output = 3.6 units per hour.

 

So you're looking at about 4kW of solar.

 

Amorn Solar have a 3.6kW grid tie system for 77k Baht. Pretty sure this does NOT include installation or anciliary items so I would expect maybe 50% on top. Also I have no idea how up to date their site is.

 

https://www.amornsolar.com/product-page/set-on-grid-3-6k-solar-cell-kit-s-phase

 

 

I agree with your calculation. Another way: 2 weeks is 1000 THB so 1 month a bit over 2k THB or about 500 units. One kWp will generate roughly 120 units a month so 500 / 120 = 4.17. 4kW system size and 3.6kW is close enough (we don't want to oversize as it'll be wasted).

 

That package from Amorn is overpriced by about 10k THB. Amorn in general is a bit expensive. I'm sure one can find those 330W poly panels for less than 4k THB and that Growatt inverter (exactly same as I have) can be found for say 27k THB from reseller from a quick google search I did (maybe cheaper from Growatt in BKK directly). So 10 x 4k + 27k = 67k. And as I said panels can be found cheaper. But on the other hand Amorn has many shops around the country and probably will honor warranty claims so there's that.

[sfokevin]

3 hours ago, eisfeld said:

I'm sure one can find those 330W poly panels for less than 4k THB

Amon has a special price and I’ve seen the same price at Global house...

 

https://www.amornsolar.com/product-page/%E0%B9%81%E0%B8%9C%E0%B8%87%E0%B9%82%E0%B8%8B%E0%B8%A5%E0%B8%B2%E0%B8%A3-%E0%B9%80%E0%B8%8B%E0%B8%A5%E0%B8%A5-330-watt-24v-poly-crystalline

 

Here is a recent thread where someone is doing a mini system...

https://forum.thaivisa.com/topic/1114966-solar-cells-330w-or-165w-for-sale-in-chiang-mai/#comments

 

Edited August 18, 2019 by sfokevin

[sfokevin]

4 hours ago, Crossy said:

Yeah, I'm sorely tempted to just install a small system and hope the meter reader doesn't notice the disc going backwards.

These charge controller have a built in power usage sensor that clips on the power line in and limiting system that you can set so it never produces more electricity than the house would consume (no flow out to grid)...

https://www.lazada.co.th/products/made-in-italy-1000w2000w-solar-power-grid-tie-inverter-with-limiter-110220v-eu-plug-i302782729-s522062224.html?

Edited August 18, 2019 by sfokevin

[Crossy]

Yeah, the hybrid inverter I linked to earlier has an export-limit function, excess solar can be diverted to the batteries and used as needed or at night (you could even export from the batteries at night).

 

EDIT I could actually adapt the Arduino based mains monitor I made a while back to do that as it understands negative power. Brain is now going into overdrive ????

 

[KhaoYai]

On the subject of meters running backwards, I can understand how that works.  I remember years ago going to a house in the UK where the old style disc meter had been taken off its mountings and was hanging horizontally. When I asked why this was, I was told that the meter had initially been broken off its mounting board accidentally and they'd discovered that it stopped moving.  I found that a little hard to believe until I cranked over and looked. There was clearly load being used as several appliances in the house were switched on yet the wheel inside the meter was stationary. I guess they are driven by some form of magnetic field?

 

Surely at some point Thailand will move on to digital meters - I doubt they will run backwards. If that's the case, assumimg they do change to digital, what's likely to happen? Blow the meter?

Edited August 18, 2019 by KhaoYai

[BritManToo]

4 minutes ago, KhaoYai said:

but surely at some point Thailand will move on to digital meters - I doubt they will run backwards. If that's the case, assumimg they do change to digital, what's likely to happen? Blow the meter?

Quite a lot of 'old style' meters have a clutch inside.

The wheel can turn backwards, but the counter doesn't.

Other electronic meters don't count back either, but are happy to accept your electricity free.

Some digital meters in the USA count forwards no matter what direction the current is flowing.

You can buy GTIs that have a current detector for the incoming mains that won't feed back no matter what.

Edited August 18, 2019 by BritManToo

[Crossy]

2 minutes ago, KhaoYai said:

Surely at some point Thailand will move on to digital meters - I doubt they will run backwards.

 

Digital meters are quite capable of running backwards, but of course they have a software switch to allow or disallow export.

 

Even if they don't run backwards, the only effect on solar users is that they won't get credied for the power the now "give" to the supply authority.

 

[KhaoYai]

6 hours ago, sometimewoodworker said:

And doing it the legal way through the PEA is likely to add roughly 100% on to the system + installation charge as well as several months.

This was one of my concerns without knowing any of this - I'd wondered if the PEA would insist that an 'appoved' system is used or maybe that they did the work - either way the price would be +++.  Its a bit like taking your car to a main dealer for service/repairs - you are not assured of better service but you are assured of a bigger bill (ex mechanic so I'm biased ????)

 

What I'd hoped to do was to fit the panels etc. myself but use an electrician or the supplier to do the electrical part.

 

The system that Crossy mentioned from Amorn sounds interesting - I think I have enough information for now. I won't be starting until well in to next year so there's plenty of time.  At the moment I just need to understand the basics so that when I design the house, I do so with solar power in mind.  I think the next step is to talk to the PEA and see what their views are.

Edited August 18, 2019 by KhaoYai

[ArranP]

Take your electric bill and divide it by 5 ( 5 baht per kwh ) this will tell you how many kw you use per month. I just finished installing mine, I sourced the components myself and got a local buider to put up the panels, I am off-grid.

 

INVERTER - 1x EASUN POWER 5000W Solar Inverter 5Kva 450Vdc PV 80A MPPT Parallel Inverter 48V 230V 80A Battery Charger - $780 includes import tax and door to door

 

Can link 9 together in parallel to make 45000W

https://www.aliexpress.com/item/32899640591.html

 

PANEL - 10x Bluesun mono solar panel 96 cells 450w - $1350 ( excludes shipping & import tax )

 

Panels have to come via ship to import tax and domestic courier were hefty so can add another 50% onto this price.

 

Currently the best deal is Amorn solar 330W panels 4,000 baht each ( my system would need 14x 330W panels )

https://www.amornsolar.com/product-page/แผงโซลาร-เซลล-330-watt-24v-poly-crystalline

 

BATTERY - Prismatic - 48v200ah BMS ( 100A ) included. - $1860 ( including door to door, just bought so waiting for import tax bill )

 

https://l.facebook.com/l.php?u=https%3A%2F%2Fwww.alibaba.com%2Fproduct-detail%2FCustomized-Solar-System-Battery-10KW-LiFePO4_62213076487.html%3Ffbclid%3DIwAR0MKXuUUkyspe-y6zHgvGe2482jqmOCtXE4ITI6rHBWpSF-AQ4k0HkPl_0&h=AT3oERFKZUk_NrqMczWqtai7evpDgDKzZ6fFGud6LKvRV3bHEX6fbqYMzJHbemLfdaW_6THfpanYhdNI_1397zL5OH7D11nLmBsZx6sFdoto1nFFGb4PrJsMe2g9t_zePCKoXhEajsHW8TWM-I9gdX3UhZuQwBf-yw

 

I will buy another battery later to connect in parallel si 48vx400ah ( 19200 watts )

 

here goes for yours....

 

• 2 x TV's  120 watts x 6 hours = 720 watts
• 3 x Aircon units  3000 watts x 12 hours = .36000 watts
• 1 x Electric oven  2000 watts x 30 minutes =  6000 watts
• 1 x Microwave 800 watts x 10 minutes = 14 watts
• 4 x Ceiling Fans 150 watts x 18 hours = 1800 watts
• Low energy LED lighting throughout  = 20 lights x 3 watts x 6 hours = 360 watts

 

total 44,894 watts per day or 1,350 kwatts per month, x 5 baht = 6750 baht per month bill 

 

no fridge ? 

 

your system without battery should cost about 90,000 baht so the pay off is 2 to 3 years I guess.. 

 

If your electric grid is reliable you can forgoe the battery and buy a grid tie invert instead. I think you sell to the grid at 1 baht per kwh and you buy at 5 baht per kwh.

 

Edited August 19, 2019 by ArranP

[eisfeld]

ArranP: In general I agree but a few corrections:

 

1. The PEA residential price per unit currently is not close to 5THB but more around 4.2THB (it's tiered). Assume your usage calculation fits the OP then he would be paying on avg 4.25THB per unit for a total of 5.7k. Here the link to the tariffs: https://www.pea.co.th/Portals/1/demand_response/Electricity Tariffs Nov61.pdf?ver=2018-11-21-145427-433

 

2. The daily/monthly consumption unit is Watt-hours (Wh, kWh) not Watts. Watts is the "speed" at which consumption/generation occurs.

 

3. I have never ever seen a break-even of 2-3 years with solar for residential or commercial installs. A good system will take around 5 years.

 

4. The current rooftop solar program from PEA pays 1.8THB per kWh but I believe (not 100% sure) that the way it's counted means you never "spin backwards", so if you use 5 kWh, then generate 3kWh, you end up with a bill of 5*4.2-3*1.8 = 15.6THB vs if it would count also backwards it would be 5*4.2-3*4.2 = 2*4.2 = 8.4THB. So depending on usage and generation patterns it can be more economical to just spin backwards to get close to 0 instead of applying for the feed-in tariff.

 

 

BTW in general I would advise to use an inverter that is approved by PEA just in case things go south later you at least wont have to buy another inverter. There are plenty to choose from. I am attaching the list to this post.

 

 

PEA_Inverter_list_14-May-19.pdf

[ArranP]

photo of my system if anyone interested.

 

inverter and wiring...  in this picture only one string of panels is connected, still waiting on the fuses to arrive for the second string.

 

 

I used this photo of a combiner box to figure out the wiring and components needed...

 

Note : The photo below shows a combiner box with wiring or an inverter with a transformer, if you use a transformerless inverter the neutral feed from the pv array should also be fused ( as in mine above ).

 

 

for a 5KW system with no battery you should be paying approx 80,000 to 100,000 baht if you do it yourself, just get a builder to put the panels on the roof, can make the roof mounts from sinualloy steel instead of buying expensive aluminium manufactured mounts.

 

 

Edited August 19, 2019 by ArranP

[BritManToo]

5 hours ago, ArranP said:

Currently the best deal is Amorn solar 330W panels 4,000 baht each ( my system would need 14x 330W panels )

https://www.amornsolar.com/product-page/แผงโซลาร-เซลล-330-watt-24v-poly-crystalline

Best current deal is through Shopee, 3,700bht for 330w PolyCrys inc delivery.

https://shopee.co.th/product/53019024/2055214342

Delivered in about 5 days.

Edited August 19, 2019 by BritManToo

[tjo o tjim]

On 8/18/2019 at 3:45 PM, Crossy said:

Yeah, the hybrid inverter I linked to earlier has an export-limit function, excess solar can be diverted to the batteries and used as needed or at night (you could even export from the batteries at night).

 

EDIT I could actually adapt the Arduino based mains monitor I made a while back to do that as it understands negative power. Brain is now going into overdrive ????

 

Looking at the manual for the unit, how would you do it?  Is there a modbus register for the export value that you would change dynamically via the Arduino?  (Does it have a modbus register list?)  Or, is there some way to change dynamically via serial?  

 

Or, is all power actually going through the hybrid  inverter, which would make it pretty trivial...

[KhaoYai]

7 hours ago, ArranP said:

Take your electric bill and divide it by 5 ( 5 baht per kwh ) this will tell you how many kw you use per month.........................................

Thanks for your post, good to hear from someone who's currently installing. Obviously nobody's electric usage is the same and I've never lived at the house longer than a month with all the items that consume power that I have now. Even so, I would hope my bill is less than 6750 per month.

 

Still, what you have posted give a lot to think about.

 

The PEA get a good deal don't they - they sell to me at 5 baht but only pay me 1 baht? ????

 

If I can install a system for 100,000 or even 150,000 that's fine.  As for payback - well it would be nice but I'm not installing solar power to save money - that is hopefully a byproduct.

Edited August 19, 2019 by KhaoYai

[Crossy]

The hybrid unit (or one of its stablemates) allows you to set priorities for solar, battery and grid, so it ought to do the job out of the box.

 

The Arduino idea was to use a number of the 300W micro-inverters and simply disconnect them one at a time based upon export power being non-zero. 300W steps are pretty coarse but it's do able.