Off Grid Hybrid System

[Silencer]

I just started a new house build and am considering whether I should go big and "go solar", even though the budget may not allow it. Since I only have estimates on my power usage (from a member here) vs actual usage data, that is what I used when I contacted a local solar company. The only change would be to go from an electric hob to a gas hob to reduce electrical needs, but the quote below included an electric hob in use. Also, I really don't anticipate high A/C usage at all which could further influence the sizing calculations. But best to go worse case and have everything that exists in the house being used on occasion. My knowledge of solar panels/cells/installation is limited to seeing panels on roofs, so zilch. I have not been tracking pricing as well although I know costs for products have been going up the last few years. Given all that, I would be very interested in comments from knowledgeable members on the following quote I received to put in a full solar hybrid system, anything that looks amiss, or anything I should add, and ofcourse any comments on costs based on a non DIY install. Btw, the company would also include a special breaker box that would prioritize certain systems (and disconnect others) during a power outage. 

 

Subject: 10 KW Solar Hybrid System with Batteries

1 pcs Deye Sun- 10 KW Hybrid , Inverter 135,000.00 THB

24 pcs 550 Watt Monocrystalline half cells Solar Panel 13.2 KW System 204,000.00 THB

incl. grounding

1 pcs Breaker Box including ATS (Automatic Transfer Switch) 25,000.00 THB

1 pcs Mounting for Panels 36,000.00 THB

1 pcs All Cables including DC Cable 4mm² 25,000.00 THB

1 pcs Installation 40,000.00 THB

4 pcs 5,0KW Lithium LiFePo4 batteries 48V 100ah (90% useable) 20 KW all together 280,000.00 THB

1 pcs Grounding 5,000.00 THB

 

If you do the math that comes out to 750,000 baht. More than I was hoping for but maybe that is close to reality.  When I don't even have an electric bill in hand, it is impossible to calculate my actual cost savings and thus ROI.  I'm of the mind that maybe I should wait until I have actual use/cost information before making this type of commitment. If nothing else, this can be a data point for others who are considering such a system. 

[Bandersnatch]

@Silencer

Solar PV should cost about ฿9/W

My 5kW hybrid off-grid inverters cost ฿36,000 each

9kWh LiFePO4 Batteries ฿68,000 each
 

Fitting plus extra components required is extra 

 

If you are building your house now spend some money on increasing insulation to lower electricity demand. My aircons are only 8,500 BTU 
 

My PEA bill last month:

 

 

 

Edited May 2, 2023 by Bandersnatch

[Jotnar]

I'd say overpriced ... here's a thread that may interest:

https://aseannow.com/topic/1268214-solar-8kw-hybrid-inverter-w10kwh-upgraded-to-20kwh-in-sept-2022-essbattery-not-diy/

 

[Crossy]

The inverter is 98k on Lazada so your installer is marking up nearly 40% on an already close to retail price. https://www.lazada.co.th/products/solar-hybrid-inverter-deye-sun-10k-sg04lp3-euau-i4546733675-s18499916427.html

 

I would certainly be getting other quotes.

 

I agree, before doing anything else do an energy audit. You don't actually need to have bills but knowing just what you want to run is the starting point. A/C how many / how big?

 

Are you really wanting to be off-grid totally, or are you looking at some form of grid-assist (so you use the grid when the solar is off due to no sun and drained batteries)?

 

Soooo, many questions before diving in with a significant investment.

 

As a quick and dirty guesstimate. 

Your system should generate about 47kWh per day = 1,400kWh per month.

 

At 4.5B/kWh that's 6,300 Baht's worth of juice each month meaning a simple ROI would be 119 months (10 years). Energy prices will go up no doubt and reduce that.

 

Do you plan to have an EV at some point?

 

For a non-DIY system I suppose that's not too bad.

 

 

 

 

[Crossy]

Addendum:- 

 

I note that the inverter is 3-phase, do you need 3-phase? That's only 3.3kW per phase!

 

https://www.deyeinverter.com/product/hybrid-inverter-1/sun5-6-8-10-12ksg04lp3.html

 

Two 5kW single-phase units running in parallel would be about the same cost and would allow the full 10kW on a single phase. An added advantage would be that if one unit fails you still have the other available.

 

[driver52]

14 hours ago, Silencer said:

 

If you do the math that comes out to 750,000 baht.

nobody on here is young enough to get a return on that sort of investment

the price is OIL is 'crashing', what does that tell us? a recession is coming........solar panels are dirt cheap now and they'll probably get cheaper in a recession...along with the other hardware....dunno where you get 750k from but isn't a 335w panel like less than 4k baht now.....the inverters are pretty cheap too

[BritManToo]

2 hours ago, driver52 said:

solar panels are dirt cheap now and they'll probably get cheaper in a recession..

Solar panels (340W) were 2,600bht in 2020, today 2023 they cost 3,600bht.

So getting 35% more expensive.

[BritManToo]

17 hours ago, Silencer said:

Subject: 10 KW Solar Hybrid System with Batteries

1 pcs Deye Sun- 10 KW Hybrid , Inverter 135,000.00 THB

24 pcs 550 Watt Monocrystalline half cells Solar Panel 13.2 KW System 204,000.00 THB

incl. grounding

1 pcs Breaker Box including ATS (Automatic Transfer Switch) 25,000.00 THB

1 pcs Mounting for Panels 36,000.00 THB

1 pcs All Cables including DC Cable 4mm² 25,000.00 THB

1 pcs Installation 40,000.00 THB

4 pcs 5,0KW Lithium LiFePo4 batteries 48V 100ah (90% useable) 20 KW all together 280,000.00 THB

1 pcs Grounding 5,000.00 THB

That pricing seems way over the top,

A 5k5 hybrid inverter can be had for 13,000bht.

No need for ATS, the inverters switch themselves, I use a breaker/fuse box that cost under 1,000bht.

Mountings can be made with little effort from 2x1 box steel (400bht for 6m)

Cables can be made from household 2.4mm twin, one 25m reel should do at about 1,500bht.

20kWhr batteries, (2 x 12kWhr NMC) @ 50,000bht each = 100,000bht.

Use your existing home grounding.

 

No need to have every electrical item in your house running from solar, pick and choose.

My home is 80% solar from 1x 5K5 hybrid inverter, 9x 340W panels, and a 50,000bjt LifePo battery.

Total cost was under 100,000bht.

Aircon/shower heaters and electric cooker powered direct from grid.

Rest of house runs from the Inverter, which switches to grid if batteries/sun run out.

Edited May 3, 2023 by BritManToo

[Crossy]

This spreadsheet may be of use for your energy audit.

 

https://diysolarforum.com/resources/system-energy-audit-and-sizing-spread-sheet.12/

 

 

[BritManToo]

50 minutes ago, BritManToo said:

Cables can be made from household 2.4mm twin, one 25m reel should do at about 1,500bht.

Pricing error, 50m x2.5mm twin = 900bht (HomePro).

[driver52]

1 hour ago, BritManToo said:

Solar panels (340W) were 2,600bht in 2020, today 2023 they cost 3,600bht.

So getting 35% more expensive.

still significantly cheaper than 5-20 years ago.....the reason inflation has gone crazy recently is they used convid as an excuse to print trillions, just look at the central bank balance sheets and those of the rich ????

Edited May 3, 2023 by driver52

[Crossy]

Yeah, I should have bought more panels in November 2021, 340W @ 2,890 Baht.

 

 

[Jenkins9039]

On 5/3/2023 at 8:50 AM, driver52 said:

nobody on here is young enough to get a return on that sort of investment

the price is OIL is 'crashing', what does that tell us? a recession is coming........solar panels are dirt cheap now and they'll probably get cheaper in a recession...along with the other hardware....dunno where you get 750k from but isn't a 335w panel like less than 4k baht now.....the inverters are pretty cheap too

Oil will crash yes, but it will also rise.

[Jenkins9039]

On 5/3/2023 at 6:14 PM, Crossy said:

Yeah, I should have bought more panels in November 2021, 340W @ 2,890 Baht.

 

 

Just moved my solar panels, adding 2 additional panels also.

 

Pre-install new panels getting rough 3,400w's constant day time.

[KhunLA]

@Silencer

750k is way overpriced, and why 3 phase

 

If considering, you need to think about your roof design now.  Our panels face S & W, which means we miss about 2hr of better production if a few were facing E.   Not really needed, but would be nice.

 

We have 8kW hybrid (Deye) & 20kWh ESS (2 X 10kWh)

As suggested, you should consider 2 - 5kW inverters.

 

We use gas hob, and have 1 induction unit (which doesn't get much use), only  because I prefer gas.   But have convention ovens, microwave, , coffee machine, 2 frigs, & slow cooker, get used quite a bit.  I bake bread every other day, of late.

 

Excess solar goes to EVs.  

 

Our usage since having (Aug 2022), <500kWh a month, when being conservative during rainy season to 1000kWh being AC abusive during dry season.  Last month was brutal, and still didn't hit 1000kWh.   House is 106m² of area, constantly cooled.

https://aseannow.com/topic/1268214-solar-8kw-hybrid-inverter-w10kwh-upgraded-to-20kwh-in-sept-2022-essbattery-not-diy/

 

Current list ????

https://www.v-e.io/wp-content/uploads/2022/06/PEA-Inverter-list-ครั้งที่-5-2565.pdf

 

Edited May 5, 2023 by KhunLA

[motdaeng]

On 5/3/2023 at 7:37 AM, Crossy said:

I note that the inverter is 3-phase, do you need 3-phase? That's only 3.3kW per phase!

eg.

if your solar panels (10 kwp) provide 9 kw of power at lunchtime, and the phase 1 uses 6kw, the phase 2 uses 2kw, phase 3 uses 1kw.

does the inventor or BMS regulate the various uses of the 3 phases? or are all 3 phases limited to 3.3kw?

 

having solar and only 1 phases seems to be easier and better, not just for financial reasons ... (?)

Edited May 5, 2023 by motdaeng

[Crossy]

From the Deye manual.

 

 

Note the AC Rated current (per-phase) of the 10kW unit is 15.2A => 3,344W @ 220V with a max of 16.7A => 3,674W.

 

The unit does seem to be able to handle a degree of imbalance but I'm not entirely sure what's meant by "Three-phase unbalanced output current", I don't think I'd want to go over about 3kW per phase.

 

[driver52]

2 hours ago, motdaeng said:

9 kw of power at lunchtime

holy moly batman, u running a sauna club and hot spa business on the side??? ????

[KhunLA]

1 hour ago, driver52 said:

holy moly batman, u running a sauna club and hot spa business on the side??? ????

It doesn't take much to rack up the kWh's.

EV ... 2.3kWh

oven ... 1.2-2.2kWh (1 unit)

shower ... 3.5kWh & up

 

Possibly running in background:

ACs

Frig (s)

Water Pump

Rice / slow cooker

Iron, washing machine ... anything with heating element or motor.

Our house, sewing machine.

 

People need to pay attention first month having, along with production.   Rainy season and production can be low or nil part of day.  10 or 20 kWh of ESS won't last long if more than a few appliances are on.

 

 

Edited May 5, 2023 by KhunLA

[Silencer]

Thank you all for your comments and information. I have a lot more leg work (computer time) and home analysis to do before making the commitment to solar. I DO NOT need to be off grid. Getting a "good" solar system (at a fair price) that addresses a significant percentage of my energy bill will be good enough, as many of you have done. I'll keep researching and get other options from the current company quote and others.

 

As for roof directions, not ideal, but maybe ok due to size. 3 roofs single sloped @ +/- 18degrees.  170 sqm facing Northeast, 105sqm facing Southeast, and 60sqm facing NW. Can add car parking area roof sloped to south as well. After 9-10AM, property in full sun at the moment.

[Crossy]

If you can get all your panels on the parking structure it would help with maintenance / cleaning and eliminate the possibility of leaks in your house roof.

 

[Silencer]

3 minutes ago, Crossy said:

If you can get all your panels on the parking structure it would help with maintenance / cleaning and eliminate the possibility of leaks in your house roof.

 

Wow! Did not think of that benefit. Maybe not all but with a reduced capacity system, I will look into that. One less worry about the roof.

[Crossy]

If you've not already have a look at this thread https://aseannow.com/topic/1120934-how-about-a-solar-car-port-on-a-budget/

 

It's expanded "somewhat" since we started and now has space for 4 cars (not that we own 4 cars).

 

 

[007 RED]

I would endorse @Crossy comments above regarding using you 'parking structure' for mounting your PVs etc if that is possible/practical.  

 

I have a small scale grid tied system comprising 4 x 415W half cut mono panels connected in series to a 2kW GTI.  The panels are mounted on our carport roof which just happens to face almost due South, with a 15^o slope (approximately), which is almost an ideal setup.

 

 

The GTI is located under the carport roof, as shown in the photos below.

 

 

FYI.... The cost of the hardware for my system (DIY installation) was 28,000 THB, give or take a few THB.

 

As will be seen from the photos above, there is enough space on the carport roof to hold far more PVs.  I estimate that it could hold 12.  That said, when I designed the system (some 2 years ago), I set a target of reducing our electric bills by 75% per month.  OK, my wife and I are not heavy electric users and we only run our ACs (living room and bedroom) when the humidity exceeds 70% - they've been running 'overtime' recently due to high heat and humidity but the system is still on target.

 

During the past 19 months our small scale system has achieved our bill reduction objective, and all being well it will have paid for itself in just under 2.5 years.

 

Good luck with your proposed project.

[Silencer]

On 5/3/2023 at 7:19 AM, Crossy said:

The inverter is 98k on Lazada so your installer is marking up nearly 40% on an already close to retail price. https://www.lazada.co.th/products/solar-hybrid-inverter-deye-sun-10k-sg04lp3-euau-i4546733675-s18499916427.html

 

I would certainly be getting other quotes.

 

I agree, before doing anything else do an energy audit. You don't actually need to have bills but knowing just what you want to run is the starting point. A/C how many / how big?

 

Are you really wanting to be off-grid totally, or are you looking at some form of grid-assist (so you use the grid when the solar is off due to no sun and drained batteries)?

 

Soooo, many questions before diving in with a significant investment.

 

As a quick and dirty guesstimate. 

Your system should generate about 47kWh per day = 1,400kWh per month.

 

At 4.5B/kWh that's 6,300 Baht's worth of juice each month meaning a simple ROI would be 119 months (10 years). Energy prices will go up no doubt and reduce that.

 

Do you plan to have an EV at some point?

 

For a non-DIY system I suppose that's not too bad.

 

 

 

 

Hi Crossy. I know you like to run the numbers (and we all appreciate that!) so I thought it would be worthwhile passing along to you the company's numbers for the system described.  Generation:  1584 units/month average, equating to 11,088 baht/month or 133,056 baht/year (at 7 baht unit price).

Edited May 5, 2023 by Silencer

[Crossy]

23 minutes ago, Silencer said:

Hi Crossy. I know you like to run the numbers (and we all appreciate that!) so I thought it would be worthwhile passing along to you the company's numbers for the system described.  Generation:  1584 units/month average, equating to 11,088 baht/month or 133,056 baht/year (at 7 baht unit price).

OK

 

13.2kWp is realistically going to provide 13.2*.8*4.5 kWh per day = 47.52 => 1,425kWh in a 30 day month. So, they are a little optimistic, but not too bad.

 

Energy prices are definitely on the up, but I really don't see 7 Baht a unit any time soon. But ...

 

If we say a "fairly realistic" 5 Baht a unit then that's 7,128 Baht per month!  85,536 Baht a year.

 

For real-world numbers - Our 10.6kWp system generated 11,225 kWh in the year to May 2023 (935kWh per month)

 

[motdaeng]

33 minutes ago, Silencer said:

 Generation:  1584 units/month average, equating to 11,088 baht/month or 133,056 baht/year (at 7 baht unit price).

to get that numbers, you have to use every single produced kWh everyday all year!

i think that would be only possible if you are using much more than 1584 units/months or (like some do)  feeding the excess back to the grid!

 

luckily we are not yet at 7 Baht per unit ...

[h90]

On 5/3/2023 at 11:46 AM, BritManToo said:

Solar panels (340W) were 2,600bht in 2020, today 2023 they cost 3,600bht.

So getting 35% more expensive.

yes because Europe buying a lot, but I assume they'll drop again in price

[KhunLA]

I'm not seeing ฿7 / unit coming anytime soon.   Took 20+ yrs to go from ฿3.5 ish to not even ฿5 yet.

@Silencer

What's your PEA/MEA usage now per month, as with a proper built house, and inverter ACs, it's a good chance it will remain about the same, if using a bit more (ACs) or bit a blt less or more than present bills.

[Silencer]

4 minutes ago, KhunLA said:

I'm not seeing ฿7 / unit coming anytime soon.   Took 20+ yrs to go from ฿3.5 ish to not even ฿5 yet.

@Silencer

What's your PEA/MEA usage now per month, as with a proper built house, and inverter ACs, it's a good chance it will remain about the same, if using a bit more (ACs) or bit a blt less or more than present bills.

Unfortunately, I don't have a "bill/usage" figure to go by as I'm just starting the build now on Samui. 70% of concrete work done. I have estimates for kW usage and amp loads though, although I will switch to gas hob to remove 6kW from that previous estimate and now will go with more extensive water collection/retention and filtration system. I will be using aac block and SCG green roof insulation (and other tips read on the forum), trying to do what I can to minimize a/c, fridge, workloads. Solar was a luxury "afterthought", which I'm assessing now. I like the idea of initially starting with 2  5kW inverters and a dedicated carport roof for the panels. Ultimately I might add this system AFTER the house is built as I don't see any great advantage in designing the system into the existing build schedule.