Thinking about solar system for Life Style Block - 62kw is the average daily usage.

[Dukesolar]

Not really sure where to start, but I like DIY and have setup small system to run 240vac fridges etc at our caravan site.
SO I know enough to be dangerous but do have access to a couple of electricians for help.

Usage is 22,700KW per year - so that mean 62kw daily average.
Winter peak is 73kw and summer is down to 48kw.
Power in NZ is a rip off and we constantly are paying about $500 - $600+

Just thinking .... but would a 60kw system be feasible?

455w panels / 60kw = 131 panels - that is huge.... (60000w / 455 w= 131 panels - is this correct, seems to simple...
I would like to mound the panels on the ground... this is about 100m from where the inverter would be mounted.
I like batteries..... I like to solar it is such a great thing.

One of the main things I like is having this system installed and paid for in about 10yrs.... so when we retire we have a much smaller power bill.

Any advice appreciated.

 

[frasere2]

Okay, go to PVwatts and punch in your numbers, you will be astounded how much 60kw makes. If you have a 30kw system, and install it flat or 10° East/West, you will get about 38000kwh a year. That's more than you need, by far. This assumes you have some sort of net metering. If you don't, you will need batteries and an ac coupling or at least a good buy-back rate on your electricity. However, I noticed most of the good buy back rates are for 10kw and under systems. Also, if you are trying to even out your monthly production, you can change the tilt angle until you get what you need in the winter, but do account for the extra inter row spacing (if you have more than 1 row of panels) as the angle increases. Playing around, using 35° tilt and 20kw DC system, you can get about 2100 kwh/month in winter. I'd oversize it just to be sure.

 

[SparkyJJO]

FYI - kW and kWh are related but very different.
kW is power, instantaneous.
kWh is power usage over time (h for hour),or capacity of storage.
You can use 60kWh in a day from an inverter capable of 10kW for example by pulling 10kW for 6 hours.

 

[G00SE]

With rough napkin math, 12kw of panels would produce ~40kwh-60kwh per day.
12000x5hoursx0.8efficiency.

In your example, 60kw of panels/131-455w panels more like 250-300kwh per day.

A kilowatt hour of energy is a kilowatt of power sustained for one hour

 

[Dukesolar]

Ahhhh moment.... the thought of 100 panels was just to scary and the cost OMG.
The penny has dropped.... the missing link.

Thanks very much, so based on my numbers I need 12kw of panels, how much loss will the voltage drop be for 100m / 300ft - panels to inverter?
So 12kw / 455watt panels = 26 panels - lets round up to 30 panels just for fun. 30 x 455w = 13650kw x 5hrs x 0.8 = 54,600KWH per day.
2 rows of 15 panels - interesting question is the paddock is slopped.... like a gully. it will lose the evening sun early, but get the morning and all day sun. In winter we would still need to buy power as we use up to 73kw or more.... I like 30 panels idea..... so much better.

 

[G00SE]

Exactly!
Panels are getting cheaper as well. Inxeption . Com Carry’s some pallets in the 370-550w range that can be as cheap as $2k for a pallet of 31
Edit: disregard the Inxeption idea. Didn’t realize your toilets flush the opposite way of mine. Delivery may be prohibitive

 

[Danke]

Ahhhh moment.... the thought of 100 panels was just to scary and the cost OMG.
The penny has dropped.... the missing link.

Thanks very much, so based on my numbers I need 12kw of panels, how much loss will the voltage drop be for 100m / 300ft - panels to inverter?
So 12kw / 455watt panels = 26 panels - lets round up to 30 panels just for fun. 30 x 455w = 13650kw x 5hrs x 0.8 = 54,600KWH per day.
2 rows of 15 panels - interesting question is the paddock is slopped.... like a gully. it will lose the evening sun early, but get the morning and all day sun. In winter we would still need to buy power as we use up to 73kw or more.... I like 30 panels idea..... so much better.

Panels are going for around $.10/W from China now. I have no idea what the shipping cost is to Auckland. But I imagine you’re gonna average less than $.20./W for a few pallets or more when you include shipping.

So I would add as many panels as you can afford. On a really overcast day, I’ve still been getting over 10% out of my panels. I’m going to try vertical mounting where I might get even more production. I will be off grid, so I will have enough panels to operate even during cloudy weather.

As you are grid assisted, you probably don’t need many batteries like I do. Batteries are the most expensive part of my system.

 

[Dukesolar]

so there looks to be no limit with power shop. Frank Energy said - 50kw or less. What does that mean.....So my system based on 54,600KWH or total 54kw... which is a large system bigger than my proposed 13kw..

 

[Dukesolar]

Yes Grid assisted... but like the battery idea.

 

[Danke]

View attachment 193770so there looks to be no limit with power shop. Frank Energy said - 50kw or less. What does that mean.....So my system based on 54,600KWH or total 54kw... which is a large system bigger than my proposed 13kw..
View attachment 193774

You need to find out what your utility company allows for the maximum size of your system to sell back. Here in the states, it is usually based on the AC capacity. So that would be your micro inverters or string inverters. One strategy people employ is to undersize the inverters to the panels that have multiple orientations. In that way with more panels, producing throughout the day, will result in more overall power production to sell back, and still stay under the maximum utility company allowed of AC generation.

If there is no limit in the size of your system, then larger inverters relative to panel size (avoiding clipping) and optimum orientation (true north for you?) would harvest the most energy for sell back.

 

[Bop]

Waves from Australia...
You won't need those huge numbers of panels- my old system in Brisbakers ran at 32kwh a day in summer, about 27kwh a day in winter- and pretty much zero'd the electricity bill at the time (2016-2020)
It was only 22 panels, total of 6kw, with a 5kw gridtie inverter (3kw facing east, 3kw facing west)
(you still seem to be mixing up kw and kwh- my 6kw of panels system produced 32kwh a day)

3kw of panels (east wing) visible, same on the other side...


Daily output 31.8kwh

Last bill before I moved...

(that gives both the total generated by the panels and the daily consumption by the house for 3 months...)
We made 1551.3kwh from those 22 panels during that 3 months, and only used 632.7kwh of electricity from the grid... (basically thats night use- we used to leave the A/C running all day on hot days when noone was at home- just for the rather elderly cats lol- turned on at 10AM and turned off at 4PM on its timer...)

 

[Bop]

I am currently building my own 'retirement home' on a rural block here in Australia- currently living off 6x 250w panels (which give me about 7-8kwh a day in good conditions)- which pretty much would have just run the old house (2-3 people)
As it is this runs the caravan, I do all my cooking on electric, can run the welder and plasma cutter when I need them, this laptop runs 24/7...
I suspect you are seriously misreading your numbers and mixing up kwh with kw...
6 of those 7 panels run the shed and caravan...


My 'camp kitchen' in the shed (hate cooking in the caravan- it gets it hot and it uses up LPG- $$$$) lol

Run the welder or the plasma cutter...


Waves from the middle of this (40 acres of it is mine lol) (thats from a drone on the front road- the arrow is where I am sitting right now lol


I got 72x 250w exgridtie panels sitting in the shed- total of 18kw that I got from an installer for under $2000 (I took out two grand in cash, put $40 of diesel in the tilt-tray, and the rest went to him), that will make me enough to run the house, a workshop (including lathe and mill) and charge an EV all with ample to spare (that 18kw will be generating close to 100kwh a DAY...)- just got to finish building the house itself lol so I can put them on it...

That's them under the tarp above on 'moving in day'...

And thats all the rest siting in the shed waiting for me to finish building the house (could take a while- it took me over a year living at 'the camp site' to build the shed...)
The whole system (including 20kwh (16x400Ah LYP lithium cells), 12kw LF inverter, 4 60A MPPT external charge controllers, racking etc cost me a grand total of $17500... getting the mains (runs out the front) connected I was quoted $42k!!!- and would still get bills afterwards AND only have a 8kw limit on the house and shed (SWER)...
Um- yeah, but no thanks lol