Sophon

I don't really care whether the panels are blue or black, to be honest the lack of symmetry if having 9 panels mounted in two rows would bother me more. Following your link, I can not find all your panels at your quoted prices. However, I did find this additional 340 w panel on sale: link. I think Crossy have previously bought that panel. I assume your 410 w panel is this one. link The only 450 w panel I could find is this one, but the price is lower than you quoted link The slight problem with the higher rated panels is, that they are slightly bigger and heavier. The metal for my structure comes in lengths of 6 m, so with the 340 w panels being 99 cm x 196 cm they fit neatly with two rows of 6 panels. The 450 w panels are 104 cm x 210 cm, so would not fit as neatly. But that's just a slight niggle, it will not be the deciding factor. I have seen Crossy say several times that if there is no limitations on mounting space, he would go for the most watt per Baht. With the 340 w JinYuan panels on sale, that would at this time make them the best value for money at THB 41,880 for 12. I really appreciate you taking the time to dig up and post information for me.

No, I am not sure that 12 panels is enough but I believe they probably will be. If it turns out it's not enough I can always add more later. With your own estimates of 75% efficiency and 6 hours of sunlight per day and 12 pcs 340 W panels, I make it a production of 340*12*.75*6 = 18 kWh on an average day. Our consumption over the last several years have been between 11-12 kWh per day, so well below the average expected 18 kWh output from the panels. When we get our new EV, our consumption will probably increase by about 3 kWh per day, so still below the 18 kWh/day. I appreciate that averages are just that - averages. There will be days when we use more than our normal 11-12 kWh, and there will be days when the panels produce less than the average 18 kWh. Most days the panels should be able to cover our consumption, and on days where they are not, well that's what PEA is there for. Please don't apologize for giving information I may already be aware of. As I am a new to this there is a good chance the information you give is something I don't already know. And even if I did know something already, it's always good to have information reinforced and it could also be of benefit to other people.

Because the inverter will be located 50 m from the house, so it would require a second buried cable as well as a major rewiring of the house. As I mentioned before, I wouldn't generally charge from the mains as that would be counterproductive, but maintaining a small charge to give UPS functionality could possibly be helpful. I am just in information gathering mode at the moment, trying to ascertain what is possible and what is not. Then a few months down the line when i am ready to go, I will be better equipped to decide how to design the system.

I obviously don't want to have the power go out, an important part of the project is to avoid that. A 5 kW inverter would easily supply my whole house, the only thing I would have to avoid is charging the EV, especially if I in the future install a 7 kW home wall box.. What I would like to achieve is: When PEA power is on, I want to supply the whole house and also have the ability to go above the 5 kW inverter limit (when charging the EV). When PEA power is off, I still want to supply the whole house, but will manually take care not to use the most power hungry utilities (i.e. EV charging) to avoid exceeding the inverter limit. But how would I connect the house load to the inverter. I assume that there must always be power going to the essential output port, but that it is limited to 5 kW. The non essential output port can go above the inverter limit, but will have no power when the grid is out, is that correct? So would I need to connect both ports to a changeover switch like this one (and would that work)?: default would be keeping the switch to take input from the essential load port limiting me to 5 kW power, and switching it over to take input from the general power load port when I need more than 5 kW and know that the grid is active. Would that work, and is there a more elegant solution? What would happen if both output ports were connected to the house load at the same time, without a changeover switch, would something go poof?

That sounds good. I don't foresee a situation where I would exceed 5 kW anyway, but I guess that it would be possible for the grid to be out when there is no sun and I have also run out of battery charge.

OK, so what I call an inverter is actually all the elements within the dotted line, of which the actual DC to AC inverter is just one element. So I "just" have to set up the unit in a way that suits my needs. I did say, that I had probably misunderstood something. I realize that this may work differently between different models, but can the "inverter" be set up so that it only charges from the mains if the battery falls below a certain level of charge? With regards to the essential load, can I connect the whole house to both the normal load port and to the essential load port. I assume (I know, dangerous) that the essential port is limited to the maximum power of the inverter, so I won't be able to just connect the whole house to the essential port? I don't want to split my circuits into two groups. Thank you for your explanation.

Something I have been wondering. In a hybrid on/off grid system, what happens if the grid is off and the house load exceeds the capacity of the inverter? Will the voltage drop, or how will the lack of power manifest itself?

I will keep that in mind. I guess that even a fairly weak signal will probably be OK, as the amount of data being exchanged must be quite small so slow speed should still work.

That's scary. and one of the opponents being a retired science teacher no less. Crossy, have you seen my questions from yesterday about the illustration in your pinned topic about different solar installation types? I would love to have your comments, when you can find the time.

The installation down by Tha river with the panels mounted (but nothing connected). They are 450 W panels, so with a total of 84 panels that's quite a bit of potential energy being produced.

Thank you for the additional info. In my case the inverter will be 50 m from our house, will that be likely to create problems setting up Wifi communication? My phone can pick up our Wifi signal from that distance, but I guess that doesn't necessarily mean that the Wifi module can.

According to Google map there is a Department of Land Transport office in Det Udom at these coordinates 14.921832510217909, 105.05977110663041

Thanks, so that would require an inverter with wifi functionality. Or can you somehow plug into the inverters communications port?

Yes, I have seen that. But if you check the different shops, more often than not they will no longer have your model in stock. Some shops still have stock of one variant, but are out of stock of others, the shop from your link no longer have the wifi models in stock. . And the supposed new model is showing up in more and more shops, again under the same labels as used on your model. If you click on the link in my post, that particular shop selling under the Anern label claims that your light blue one is a 2019 model, and they have a different looking model for 2021 and again a different one for 2022. Only the 2022 model is in stock. Maybe the changes are only cosmetic, and the innards are more or less the same. But you could be right, and the "newer" models could be different models rather than replacements.

It seems that your model (the blue one) have been replaced by a new 2022 model: link. Some shops still have the older model in stock.

Noise really won't be an issue, as the inverter will be located about 50m from our house, but the rest of the post doesn't sound to positive either.

To be honest, I don't really know what Wifi does on these inverters or how it works. I have seen that Crossy posts monthly stats about his solar production and consumption, and assume that the data comes from his inverter. I would like to be able to see such data, but have no idea how you "extract" it.

I am not going to buy any items for another few months, so at the moment I am just trying to gauge the options and pricing. When I am ready to buy, I will do due diligence on the seller but right now it's not an issue.

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.

You are probably correct, there is one negative review that suggests as much. What about this Must inverter: 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.

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/

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.

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.

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????

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: 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.. 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. 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.