Energy Audit

[Begginer7]

Hi everybody, thanks for all your valuable advices for pv systems, I am living in Cyprus in the EU, we have 6h sunhine in the worst winter conditions and average 9h per year. So I am involved in an offgrid project and as you say I started doing the energy audit, got a sort of kill a watt and measured my appliances, this are the results:


So hardest conditions are on winter because of the 1.5 days of autonomy and lower energy, accordning to the sheet I need one battery of 1200, panels of 300 charge controler of 30a, inverter of 300 continuous and 600 surge. I think this values are a bit low, could anyone please tell me if they look ok? Is using 1.5 autonomy days reasonable?

Instead of using hours of sunshine I used energy produced by the sun in my location per squere meter for pv 4.09, as its available in in the solar hand book website

I think correcly I am using the lower value for December, how ever I am confused about one thing this value is for 1sqr meter but panels come at all sort of sizes for example:


This Jinkha 410w panel is 2sqr met big so I am not sure how the 4.09 value applies in this case, could some one clear this out please? Am I using the value correctly?
Is this value allready including the 20% energy loss or I have to add that?

Thanks in advance
Begginer7

 

[MichaelK]

I'm sorry, but your spreadsheet appears to be an incomprehensible jumble of information that I can't understand. This needs to be formatted better.

Let's look at one data item, your refrigerator. Looking at the 651.7 value in cell H5, is that the summer watt consumption per day? Looking at the corresponding winter value, 977.6, in H13, that number does not make sense to me. I'd expect your winter refrigerator consumption to be lower, not higher? So, please present your numbers in a better format. And, you don't need to post watts to 7 significant digits.

When you say you get 6h of sun in winter, I think you are not meaning 6 sunhours, are you? I am at the same latitude as you in California, and would say the winter value for 35 degrees north is closer to 3-4 sunhours.

Since you are mentioning the same kinds of loads as at my own place, I step out on the ledge and say you need a minimum of about 3.0kWh of power per day, which is about what I use.

If you got four of the Jinkho panels that would put you at 1640W, and you could expect them to make 1640W X 3sh = 4.9kWh of power in December. I have my panels on rotating mounts, so tracking from East to West, I can almost double those numbers on a clear sunny day.

Let's say you want 4.0kWh of power per day, and need three days of power for when a storm blows through. Assume you don't want to deplete your battery less than 50%. The math would then be 4000Wh X 3days X 2fold batttery = 24,000Wh battery. At 48V that would be 24,000wh/48V =500Ah battery. For two days, that would be 333Ah. There are several good choices of batteries in that amphour range.

Those panels appear to be putting out about 42Vmp, or maybe about 50Voc. We need real specs to make a final decision, but I would say you could wire 4 panels as two parallel strings of 2 panels each. That's written as 2S2P. If the Voc is around 50, then you will need at least a 150V charge controller. For charging a 48V battery, at 50V, that would work out to be 1640W/50V charging ~ 33A. Take a look at Epever's 5415AN controller. If you scaled up to say six panels, wired 3S2P, you would need a 200V controller.

Finally, the inverter. No, 300W is not going to cut it, not with a standard refrigerator. Plan on getting at least a 1000W unit, and 1500-2000W is more likely to work well for you. Focus on pure sine-wave inverters only to power your refrigerator and electronics.

 

[Begginer7]

Hi MichaelK

Thanks for your reply, sorry for the shabby presentation, let me try to present the info better, just the energy consumption first:



If the refrigator seems low its one without freezer, this is the energy label:



There is a petrol power generator on site that I want to use sometimes on winter to fill the batteries so I need an inverter that can do that, I found this option with integrated charger from MPP solar their PIP3024MSXE with 3kw.24V.60 A PWM, its MPPT and pure sine at 700 Eur, it has an idle consuption of 25 W, I have to leave this on 24 7.

SPEC: http://www.mppsolar.com/v3/catalogs/PIP-HSE_MSE(PF1.0).pdf

Manual: http://www.mppsolar.com/manual/PIP-HSE,MSE_HSE1,MSE1/PIP-HSE_MSE manual (PF1.0) -20190717.pdf

And I want to get the lithioum SOK 24 V 100 ah battery at 1300 Eur. Is this battery equivalent to 8 acid 225ah 6 v batteries?

Plus 3 panels 410 W Jinko Cheetah at 640 Eur total.

Sok battery meter 45 Eur.

Wires 450 Eur.

So total I have 3135 Eur.

I believe this system will take me for 3 or 2.5 days of storm, the only thing is that I could reduce the autonomy because I have a profesional massive generator on site:



Am I on the right track?

 

[MisterSandals]

And I want to get the lithioum SOK 24 V 100 ah battery at 1300 Eur. Is this battery equivalent to 8 acid 225ah 6 v batteries?

SOK 25.6V x 100Ah = 2560Wh

8 x (225Ah/2 (505 usable)) x 6.4V = 5760Wh