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Solar power, can it be done DIY?


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Lots to unpack @Sophon but a few points to start with:

 

I purchased the panels locally and imported the inverters and batteries so I wasn't gouged with a big mark up. I then got a local team I had used before to do the install. 

 

I have a friend who wanted to do all the install except fitting the panels and my guy gave him a reasonable price for that.

 

Regarding the EV I would recommend going for the free wall box that comes with most EVs in Thailand as that will give you a 7kW charging speed. It will mean a 10kW or 2x5kW inverters but it does mean that you will be able to dump your maximum solar production into the car in the middle of the day and avoid curtailment.

 

1029401124_SolarCurtailment.thumb.jpg.fccde4c05f0cfb09af920e2a6c0b9b98.jpg

 

 

 

 

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1 hour ago, Bandersnatch said:

Lots to unpack @Sophon but a few points to start with:

 

I purchased the panels locally and imported the inverters and batteries so I wasn't gouged with a big mark up. I then got a local team I had used before to do the install. 

 

I have a friend who wanted to do all the install except fitting the panels and my guy gave him a reasonable price for that.

 

Regarding the EV I would recommend going for the free wall box that comes with most EVs in Thailand as that will give you a 7kW charging speed. It will mean a 10kW or 2x5kW inverters but it does mean that you will be able to dump your maximum solar production into the car in the middle of the day and avoid curtailment.

 

1029401124_SolarCurtailment.thumb.jpg.fccde4c05f0cfb09af920e2a6c0b9b98.jpg

 

 

 

 

I will definitely take the free wall box that comes with my EV, but I have read your posts (and seen the MG podcast) so suspect that the installer will refuse to install it. We only have a 15/45A meter, and our 16 sq.mm. copper cables won't support an upgrade to a 30/100A meter. And I definitely do not want to change the existing 50 m of buried cable, or get a second meter which would then require a second set of cables to be buried. In reality my existing meter should be able to cope with the wall box, but the installer won't see it that way. I will insist on getting the wall box for future install, or to sell with the car if I decide to change it in the future.

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4 hours ago, Sophon said:

and we only go above 1,000 W if the water pump or one of the kitchen appliances (rice cooker, electric kettle) is on.

How often is that?

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14 minutes ago, KannikaP said:

How often is that?

The water pump goes on whenever we use water, so many times a day but only for a short while. Rice cooker is on twice a day for half an hour or so, and the kettle once or twice for 5 minutes.

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12 hours ago, Sophon said:

Thank you for your encouragement. 

 

If I decide to do this, and at the moment I am strongly leaning towards giving it a try, I will at least initially not export to the grid. I will start out seeing how much I end up relying on the grid, and then decide if I should do some unauthorized export or not. Sooner or later we will lose that option anyway when the PEA changes our meter to a smart meter. I don't think that will be soon though, as our PEA people don't move quickly. I have for more than five years unsuccessfully tried to get them to come out and put a cover on our meter to prevent people from getting electrocuted.

DSCF0427.thumb.JPG.68bcdb8367fdbe4e322bf3b9a39aeb06.JPG

 

I read your story about "commandeering" the crane to have your solar panels lifted onto your roof.  I will not put ours on the roof, primarily because I don't really want to have them up there but also because our house have a roof construction with very limited roof space pointing in the right direction (south).

DSCF0198.thumb.JPG.580b363ba978e929b526d721fbc19a08.JPG

 

Putting the solar panels would also make installation, cabling and later cleaning and maintenance much more difficult.

 

In our case the best place for the panels is about 50 m from our house where the PEA supply goes to a pole on our land before going underground to the house. At this point the cables from PEA is spliced onto the NYY cable going to the house, so "unsplicing" the cables and connecting the inverter would be easy. It's also one of the least shaded part of our land with no shade at all between approximately 7 in the morning and 5 in the afternoon. I plan to put the panels on something like this (only smaller):

IMG_20220623_093617.thumb.jpg.895dc70324a2a835c961b53b4d7c0f66.jpg

 

I have taken the photo near our house down by Tha river, where they have just (after I took the picture) put up 84 solar panels. Not completely sure what the project is, but I suspect power for some kind of pumping station.

 

Thank you again for your info.

I totally agree with your comment about not wanting panels on your roof and that you're considering ground mounting them as per the photo.

 

Once installed they shouldn't need any serious maintenance other than periodic cleaning, but in my case that presents a 'slight' problem in so far as having to climb up onto the car port roof which is constructed with cement sheet tiles and the potential risk of one breaking when l'm standing on it and dropping 4 meters onto the concrete floor.   At 75 that's not going to have a 'happy ending'.

 

If l had more land, with hindsight, l would have my panels ground mounted.

 

Good luck with your prposed project and please keep us updated on progress.

 

 

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When looking at illustrations such as this one of a solar installation in it's simplest form it all seems fairly simple and straight forward:

1781795675_Screenshot2022-08-01122710.jpg.9d62f25222cf89d660d80c38a7dee1b2.jpg

 

Everything is connected to the on-grid hydrid inverter, and the inverter then acts as the command center deciding where to take energy from (solar panels, batteries or grid), and where to route that energy (house load, batteries or back to the grid). 

 

The illustration posted above by Tubulat..
Solar..png

 

basically shows the same, but just adds more details.

 

But when I then see other illustrations like this one from Crossy's pinned topic about types of solar installations, I start to question if my understanding is correct or if there is something I am missing.

1042308740_SolarOn-GridHybrid.jpg.cfb7e5a12e08128efe143b10a4a33af1.jpg

 

Here it seems not everything is controlled by the inverter, instead there is a MPPT charge controller, a mains charger and control electronics (in addition to the inverter) connected to the battery and it's not clear to me exactly how these elements are connected.

 

Mains charger:

What's the point of the mains charger? Is it just a fail safe addition to make sure that the battery pack is always charged, even when the solar panels do not produce enough power to both cover the house load and keeping the batteries charged? If that is the case, then I can kind of see the logic in an officially sanctioned installation, when the panels don't produce enough power the batteries are kept topped up from the mains, and when there is excess power from the panels energy is then routed back to the grid. But even so, it doesn't seem optimal given the low feed back tariffs.

 

In a non-sanctioned solar installation where you are not allowed to feed energy back to the grid, using a mains charger seems counter-intuitive. I would want to keep such feed-back to a minimum, so topping up batteries from the grid would mean, that you have nowhere to feed the energy to when your panels produces excess energy. You would either waste the energy or have to feed it (illegally) back to the grid. The one situation where I can see it making sense, is if you have a highly unreliable grid.

 

But maybe I have completely misunderstood the point of the mains charger.

 

MPPT charge controller:

As far as I understand, the charge controller regulates the charging of the batteries, which will prolong the battery life. But doesn't most solar battery packs come with some form of battery management system built in? So can the MPPT and the BMS live together, and how

much better off are you with a charge controller?

 

Control electronics:

What are the "control electronics" controlling? Are they helping out of the charge controller/mains charger?

 

House load:

The illustration shows two connections from the inverter to the house load and one directly from the grid to the house. Again, it's not clear from the illustration how you would go about connecting this, which maybe makes it seem more complicated than it really is?

 

Is the direct connection from grid to load some kind of bypass in case the solar system develops a fault? If not, then what is the purpose of this direct link?

 

One of the connections between the inverter and the house load is marked "Essential Power", so presumably this is items such as refrigerators, a few lights, fans etc. that you find essential to have on in case the grid is down and your panels are not producing enough power. The unmarked connections is then the rest, i.e. of the "non-essential" items?

 

The only way I can think of that would make this work, is if your house circuits are separated into essential and non-essential circuits. In my case that would mean a rewiring of the house, something I definitely would not want to do. Normally our power cuts only lasts about an hour, and if one occurs while there is little/no sun and the batteries almost drained I will just make sure to manually turn off everything I don't find essential. It would be helpful though, if it were possible to set up some kind of alarm system in case of power cuts, as we would no longer necessarily be aware of the power being out until the batteries run out. I guess I could ask the neighbour to call us.

 

In reality it wouldn't be a big deal, as even in the worst case scenario (grid down, no sun and batteries empty) we would still be no worse off than we are today. Most of our power cuts happen late afternoon when the thunderstorms roll in, so even on a cloudy day the batteries would typically have some power. 

 

So are Mains charger, Charge Controller and Control electronics really essential/necessary/helpful elements? I just want a simple system without unnecessary complications. Of course, if there is a strong argument for including something I am willing to do so, but it should be something that gives me real benefits.

 

I have no doubt got a lot wrong above, so please correct my misunderstandings.

 

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No-one has yet commented on my cost estimate and guesswork about what equipment I will need from my opening post. Does that mean that I am reasonably close, or is everyone just lost for words at my level of ignorance😉

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lots of info above
i will state the obvious
as far as calculating costs go
it is impossible to predict the cost of electricity in 5-10 years time
fiat currencies are losing value quicker than ever
it may be better to spend money now rather than later
if you buy Ni-Fe batteries
you will save even more as they last 50 years

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19 minutes ago, Sophon said:

No-one has yet commented on my cost estimate and guesswork about what equipment I will need from my opening post. Does that mean that I am reasonably close, or is everyone just lost for words at my level of ignorance😉

Really depends on what components, brand, version of, and from where purchased being used.  

 

China ... cheaper, should be, maybe

LAZ ... less than local, maybe

Global (chain stores) ?

From Installer ... probably a bit higher, but warranty better...maybe, if still around in 5+ yrs.

 

Prices fluctuate greatly, with options; wifi, pure sine, microinverters on panels, programmability, UPS protection/built in vs add on

Edited by KhunLA
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Posted (edited)
14 minutes ago, patman30 said:

lots of info above
i will state the obvious
as far as calculating costs go
it is impossible to predict the cost of electricity in 5-10 years time
fiat currencies are losing value quicker than ever
it may be better to spend money now rather than later
if you buy Ni-Fe batteries
you will save even more as they last 50 years

 

11 minutes ago, KhunLA said:

Really depends on what components, brand, version of, and from where purchased being use.

 

Prices fluctuate greatly, with options; wifi, pure sine, microinverters on panels, programmability, UPS protection/built in vs add on

I realize that it's kind of a "how long is a piece of string" questions, but I am just looking for an idea of whether it can realistically be done for around the quoted figure THB 150k (not including building the structure for the panels). I have based my estimate on equipment other people have linked to on Shopee, Lazada:
5 kW on-grid hybrid inverter THB 25,000-50,000

10-12 solar panels 340W THB 40,000-45,000

10 kWh battery storage THB 50,000-80,000

Bits and bobs THB ?

 

I can go higher than that, but if my estimate is completely unrealistic and the minimum cost would be say THB 300k then the project would no longer make sense.

Edited by Sophon
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1 minute ago, Sophon said:

 

I realize that it's kind of a "how long is a piece of string" questions, but I am just looking for an idea of whether it can realistically be done for around the quoted figure THB 150k (not including building the structure for the panels). I have based my estimate on equipment other people have linked to on Shopee, Lazada:
5 kW on-grid hybrid inverter THB 25,000-50,000

10-12 solar panels 340W THB 40,000-45,000

10 kWh battery storage THB 50,000-80,000

Bits and bobs THB ?

 

I can go higher than that, but if my estimate is completely unrealistic and the minimum cost would be say THB 300k then the project would no longer make sense.

Inverter & panels in the ballpark.

ESS/battery will be on the upper end of that

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2 hours ago, Sophon said:

 

I realize that it's kind of a "how long is a piece of string" questions, but I am just looking for an idea of whether it can realistically be done for around the quoted figure THB 150k (not including building the structure for the panels). I have based my estimate on equipment other people have linked to on Shopee, Lazada:
5 kW on-grid hybrid inverter THB 25,000-50,000

10-12 solar panels 340W THB 40,000-45,000

10 kWh battery storage THB 50,000-80,000

Bits and bobs THB ?

 

I can go higher than that, but if my estimate is completely unrealistic and the minimum cost would be say THB 300k then the project would no longer make sense.

i just bought 3 x 48v Growatt inverters at 32k baht each
also paid just over $5k for 3 x 15kwh batteries (48v x 300ah) from China

the selection of batteries currently here is very limited so had to order direct from China
cost is about 2/3 of the price buying local, if you can find
finding the batteries was the headache part TBH
not bought panels yet

Ni-Fe batteries cost a bit more but save you in the long run, not sold locally afaik
your estimates are about right
although you can get 5kwh inverters from 15k baht
seeing as you are going on grid
have you considered no batteries ?
or a small battery just to tie you over till 10pm, and for morning before sun comes up
(10pm to 9am is off peak hours, half price)
all depends what time you use power the most

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3 hours ago, BritManToo said:

As i understand it, in order to have the ability to export to the grid, it has to be a hybrid on-grid inverter. I can get a no brand on-grid inverter similar to the one you bought for about THB 8k more than yours:

image.png.30fed296ac65a3bf18fe00d78c3e8f0b.png 

 

link

 

Occasional export after a few days of little sunlight (and therefore relying more on the grid) could quickly recoup that extra investment. Anyway, it's always nice to have the option.

 

It sounds like you say it should be possible to achieve my goal for somewhere in the THB 150k region. I assume that other bits and bobs like cabling, breakers plugs etc. will not be a major expense (i.e. less than THB 10k)? I am only talking about the DC items, I have 16 sq.mm. NYY cable left over to make the necessary changes to the main supply.

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40 minutes ago, patman30 said:

i just bought 3 x 48v Growatt inverters at 32k baht each
also paid just over $5k for 3 x 15kwh batteries (48v x 300ah) from China

the selection of batteries currently here is very limited so had to order direct from China
cost is about 2/3 of the price buying local, if you can find
finding the batteries was the headache part TBH
not bought panels yet

Ni-Fe batteries cost a bit more but save you in the long run, not sold locally afaik
your estimates are about right
although you can get 5kwh inverters from 15k baht
seeing as you are going on grid
have you considered no batteries ?
or a small battery just to tie you over till 10pm, and for morning before sun comes up
(10pm to 9am is off peak hours, half price)
all depends what time you use power the most

Almost two thirds of our consumption is when the solar panels would produce no or little energy, so the savings would be minimal. Sure, I could export (unauthorized) to the grid, but who knows how long that would last. Besides, if I am going to do this I want to go all in and get all the benefits and flexibility of having power even when the grid is down. Even if it from a purely financial point of view would make more sense to use the grid for energy storage.

 

Would you be willing to share the contact information for your battery supplier in China/

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10 minutes ago, Sophon said:

As i understand it, in order to have the ability to export to the grid, it has to be a hybrid on-grid inverter. I can get a no brand on-grid inverter similar to the one you bought for about THB 8k more than yours:

link

 

Occasional export after a few days of little sunlight (and therefore relying more on the grid) could quickly recoup that extra investment. Anyway, it's always nice to have the option.

 

It sounds like you say it should be possible to achieve my goal for somewhere in the THB 150k region. I assume that other bits and bobs like cabling, breakers plugs etc. will not be a major expense (i.e. less than THB 10k)? I am only talking about the DC items, I have 16 sq.mm. NYY cable left over to make the necessary changes to the main supply.

 

Be very careful with these low-cost hybrids, I'll pretty much guarantee that this unit does NOT do export.

 

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28 minutes ago, Sophon said:

Occasional export after a few days of little sunlight (and therefore relying more on the grid) could quickly recoup that extra investment. Anyway, it's always nice to have the option.

Waste of money IMHO for the ability to illegally export. 

Edited by BritManToo
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Posted (edited)
28 minutes ago, Crossy said:

 

Be very careful with these low-cost hybrids, I'll pretty much guarantee that this unit does NOT do export.

 

You are probably correct, there is one negative review that suggests as much.

 

What about this Must inverter:
image.png.f3d021a6e46548dc54e035cf564cb25a.png

link

 

I am very confused by the pricing for this unit, though. The 5.5 kW with wi-fi plug is priced at THB 41.279 while the 5 kW with wi-fi is priced at THB 44.888. Seems strange. Without wi-fi the 5 kW version is cheaper than the 5.5 kW version, and it is also the exact same price as the 5.5 kW version with wi-fi. So maybe they just entered the wrong price in the system for the latter. 

 

I haven't completely decided on whether to go for the on-grid or off-grid hybrid. What matters most to me is that the inverter is able to "top up" from the net, is my consumption exceeds what it can supply from panels plus battery.

Edited by Sophon
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6 minutes ago, Sophon said:

What about this Must inverter:

 

MUST inverters DO do export - but IIRC there's a thread somewhere on problems with the beast, including poor export performance 😞 

 

Of course YMMV!

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7 minutes ago, Sophon said:

I am very confused by the pricing for this unit, though. The 5.5 kW with wi-fi plug is priced at THB 41.279 while the 5 kW with wi-fi is priced at THB 44.888. Seems strange. Without wi-fi the 5 kW version is cheaper than the 5.5 kW version, and it is also the exact same price as the 5.5 kW version with wi-fi. So maybe they just entered the wrong price in the system for the latter. 

Very brave to buy from China, no brand, no warrenty, no previous customers according to the blurb. 

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20 minutes ago, BritManToo said:

Waste of money IMHO for the ability to illegally export. 

You could be right. Buying an off-brand can be a risk, maybe it works well and lasts, and maybe it doesn't. But then again, the same can probably be said about brand items.

 

Does your unit have the wifi function, and if so how well does it work.

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