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The MPPT range at operating voltage for the Growatt SPF500ES is 120VDC - 430VDC according to the datasheet I attached in my previous post. Does this look OK? Funny you should mention decreasing temperature... this morning it was a chilly 18⁰C on the farm... and on Wednesday it is forecast to go as low as 15⁰C.

Sorry, but I do not understand this. See attached datasheet - it states a maximum solar charge current of 100A. Growatt SPF 3500-5000 ES Datasheet.pdf

And later in the afternoon...

That is where I think that the east facing panels will come into play more... they won't help much in the event of a 3-5 day tropical storm, but typically during the rainy season the storms arrive in the afternoon.

Technically that is illegal, chaimai? You would not want to get caught and have your current spinning disk meter replaced by a new electronic one-way only meter.

This is the sort of thing that I am seeking advice on... with the new proposal using 60 x 340W panels (total 20.4kW). Three inverters or four? The jury is out on that one at the moment but as it was originally suggested by @Crossy I thought I'd follow suit. I have not selected inverters yet, but if I go with the Growatt SPF500ES off-grid hybrid inverters they are (each) designed for 6000W maximum PV array power with a maximum solar charge current of 100A. "Splitting each of the PV arrays into the right number of strings for each inverter" is something that I am having difficulty understanding... can you explain more please? (in layman's terms).

Sofar, Solax, and Growatt are the three main inverter manufacturers I am looking at currently... as all have integrated MPPT charge controllers, but I am open to suggestions for others. Yes... it is possible that panels 50 and 51 will be shaded by the elevated central roof section in the late afternoon, but if they are on the same string as the west facing panels, then the bypass diodes should help shouldn't they? That is exactly why I have started this topic now... before our house is even built. Who knows...? In 6-12 months time from now there may be some breakthroughs in technology that may change the specifics of the system we are discussing here. I have much to learn, and do not want to be conned into buying and installing a system that will not suit our needs.

Using the smaller (power and size) panels comes with a significant cost savings too... 40 x 540W = 21.6kW @ 228,000 baht. 60 x 340W = 20.4kW @ 197,400 baht I like it!

I've done another panel layout this time using the smaller 340W panels. This plan involves installing 60 x 340W panels (20.4 kW) as per the sketch below. Panels 1-12, 18-23, 38-49, and panels 50-55 facing South (total 36 panels). Panels 13-17, 31-37, and 56-60 facing East (total 17 panels). Panels 24-30 facing West (total 7 panels). Future additional panels could be mounted on top of the carport if required. I am yet to be convinced (but I am willing to listen to reasonably presented logic) that having panels that do not face south are either useless or a waste of money. I am of the opinion that PV solar panels are the cheapest components of any domestic solar power system, and will have a working life of 25 years+. The big money is in the inverters and the batteries, which will need to be replaced in time, as I am sure you will all agree on. I am also of the opinion that not only will the east facing panels help start my power generating day earlier, they will help to hide the south facing panels from the front of the house, thus increasing the "street appeal". And the west facing panels will help to extend my power generating day later. Don't forget... ALL of the panels will receive solar radiation during the peak production period of say 10am to 2pm. Thoughts?

And today they are pouring the concrete...

Well yesterday the workers were there with their machinery and dumpy level to prepare the land for the concrete slab that the rings will sit on.

Their online store prices have not changed for the past 5 months. See also this topic.

Thanks for that suggestion... I will do a panel layout based on say 340W panels to generate a similar 22kW feed to the 4 x 5kW inverters. The cost of the panels will decrease, but the cabling will increase.

Thanks @Bandersnatch... solar curtailment is exactly what I want to avoid by an having earlier in the day start and a later in the day finish generating window. Having nowhere to put the excess generated power in the middle of the day is something I want to avoid. First question about your video... do the panels on your ground-mounted solar water heater face west or do I have my directions confused? And second question, what is the slope of your roof on the lower level? You mention the fact that even the north facing panels receive some sun during the day. My build will have a flat roof, so the PV panel supports will need to be designed to enable a slope.

Yep... about 29kg each!

I would not consider Huawei inverters because you are locked into using their own very expensive batteries (about 4 x cost of similar sized kWh 48V batteries). The inverters are fine for an off-grid system, but their batteries make them too expensive for a hybrid system. Sofar, Solax, and Growatt are the three main inverter manufacturers I am looking at currently... but am open to suggestions for others.

I was thinking along the same lines... the LONGi Solar LR5-72HPH 540M Mono-PERC Half Cells are currently selling for around 5,700 baht each. Trina Vertex Backsheet 540W Mono Half Cut Cells are currently selling for around 6,590 baht each. Sunenergy Mono 540W Model SUN540-72M-H8 Half Cells are currently selling for around 6,500 baht each. Jinko 545W Mono Half Cut Cells are currently selling for around 6,690 baht each. POWITT 540W High Efficiency Solar M10 Mono Half Cells are currently selling for around 8,200 baht each.

I have been reading this forum with great interest for a while now, and as some of you know I am planning to build a new house (2 actually... a guest house as well as a main house) on our farm land in Isaan. Details and progress of that particular project can be found in this topic. Anyway, I recall @Crossy when asked if he would do the same again about 7 months ago in another topic responded as follows: I kinda like that line of thinking... it provides for redundancy should one of the inverters fail or die, and also gives total independence from the increasingly expensive PEA supply which would only be used to top up the batteries or "help" the solar array if the sun is feeling tired. Our new house will have plenty of roof space, so at the moment I am thinking to have 4 strings of 10 PV panels each connected in parallel to 4 x 5kW inverters supplying domestic 220vAC power and also a 27kWh ESS. And of course I have worked up a plan for locating PV solar panels on the roof of the Main House. The layout allows for plenty of access for cleaning/maintenance as well. The house location will be at 15⁰ 40' 45.1" N. I was thinking about installing 40 x 540W panels (21.6 kW) as per the sketch below. Panels 1-10 and panels 27-36 facing South (total 20 panels. Panels 11-14, 21-26, and 37-40 facing East (total 14 panels). Panels 15-20 facing West (total 6 panels). This would preserve the appearance of the U-shaped house (which faces East) and enable us to extend the working collection day of the panels by collecting more solar energy earlier in the day from the East facing panels, and again later in the day from the West facing panels, and also avoiding the midday peak in production that is associated with panels that all face South. Future additional panels could be mounted on top of the carport if required. I will be most interested in feedback/suggestions from members who have their own solar installations on this proposed arrangement. Also I would like to hear of suggested or recommended manufacturers/suppliers.

I have been looking at battery costs too... the Huawei LUNA2000 Battery Smart Kit 5 kWh costs around 150,000 baht, and the nRuit Powerport 10 Lifepo4 10kWh battery costs around 73,000 baht, so twice the capacity for half the price. If you are limited for space on your south facing roof and cannot extend it to add more south facing panels then I guess you are stuck with your existing structure. Not everyone is fortunate enough to have an existing property that is ideally orientated for optimal PV solar panels power production. But I would certainly be looking at manufacturers other than Huawei if your future plans include going hybrid. But getting back to your original question... has your consultant produced an energy calculation for you that demonstrates the effectiveness of individual panel optimizers if installed on the east and west facing panels? This would enable you to determine if the additional investment of 2,500 baht per panel would be worthwhile or not.

Also from the article... "Wyoming cares because it is an oil and gas state. Even though Wyoming is the least populated state in the nation with only a little more than half a million residents (0.17% of the US population), it is the eight-largest oil producer in the US."

This is a better photo of the land we want to reclaim... After the concrete ring retaining wall is built and the void filled, we will have an additional 216 sq.m. (or 54 talang wah) of usable land.

Long hot showers more likely... My 13 year old nephew was spending about 15 minutes in the shower (twice a day) earlier this week, until I embarrassed him by asking him in front of the whole family if it really took that long to wash his willy... This morning he only took 5 minutes...

In case you are wondering about all those concrete rings on the property... no, we are not going to build a shedload of toilets that need concrete ring soakaways! We want to reclaim some of that over-excavated land behind the 2m high concrete slat wall... caused by an over-opportunistic back-hoe operator who coaxed my naïve and grengjai FIL into doing it some months ago. Currently it is 4.6m from the wall to the top of the slope (x 60m long) and we want to get back as much as we can of that area. So the land just inside the wall will first be levelled using a small loader or bobcat, then a 5cm thick concrete base poured to match the existing height of the wall foundations, then the rings will be placed on top of each other (5 x 40cm high) on the concrete base so they will be the same height as the existing concrete slat wall. Plastic sheeting will be placed under the bottom layer of rings, then pulled up the sides to the top ring to act as a water barrier. The land will then be filled up to the rings, then the rings filled with land too. We will add slotted PVC pipe drains covered with crushed rock on the fill side of the plastic sheet to act as a French drain to take excess water away to the farm. It is a relatively inexpensive but ugly way to build a retaining wall, but in our case you won't see it because it will be hidden by the concrete slat wall. We plan to plant different coloured bougainvillea in the top of each ring, which will add a ton of colour to the top of the wall and eventually cascade over the side. Being a spiny plant it will also be a good security measure because anyone trying to climb over that wall in the future will be bleeding profusely.

Well we just got back from a couple of days visit to the farm. This time I took along a laser level and a tape measure so was able to determine elevations which I then forwarded to our architect and builder. I used a datum of the top of the middle of the concrete government road at the entrance to the farm, and used Google Earth to determine the RL (Relative Level). Results as follows: Elevation of top of government road = RL 168.000m Elevation of bottom of concrete wall = RL 168.180m Elevation of top of concrete wall = RL 170.180m Elevation of top of filled land = RL 169.540m Elevation of land at pond = RL 168.520m RL 168.200m is the highest recorded flood level in the area, so we should be pretty safe.

I just answered that one for you in the other topic.