Solar Panel Setup

It won't be KV, but kW or kVA.  KV is kilovolts, kW is kilowatts and kVA is kilo volt-amperes.


Start by looking at the rating plates of each appliance - usually hidden on the side or back, or in the instruction manual.  Then add up all the things you want to run simultaneously.


If you want to keep running during a power cut, then you are going to need batteries, as well as solar panels.  It isn't going to be cheap.

Actually you will need rather more panels than even that calculation suggests, as the sunshine will be on full strength for a fraction of the 24 hour day, but presumably the load is not, so during the day you need to not only supply the full load, but also to generate enough charge the batteries as well, to supply you over the night time,and perhaps when the sky is cloudy - where on the planet are you ? Here in the UK the effective solar flux is about 1/4 to 1/3  of its peak value on an typical not very sunny day.. and in the winter perhaps 100W lands on each m2 of panel compared to ten times that on a bright summers day. Note also that perhaps a fifth of what lands on the panel  turns into electricity.

Equally you may decide that for off grid days you do not need anything like the full load you first thought.

I strongly suggest you read around the subject fully  and think hard before parting with any money.

Mike.

To add to my previous post, the panels themselves will be rated in kWp - kilowatts peak.  That's the power you get on a sunny day, when the sun is shining straight onto the panels, but only if it's not too hot.


Bear in mind what mapj has said.  Don't assume that 4 kWp of panels will give you 4 kW of power all day.  It will be a lot less than that, and will only peak at one point in the day when the sun is in the right place in the sky.  Clouds make a big difference.  Even light clouds can drop the generated power to 1/10 of the nominal value.

one other thing to keep in mind is that at night you will need to be running your lights, cooker etc, and this will be off the batteries, as previously mentioned you'll need to calculate all the power required to run these systems, but also in amp-hours as this will let you know how long you can run them for as well. If your serious about going off-grid, then also look at solar water heating, (pipes on the roof). this will reduce a lot of power, and also changing your motors over in the appliances to 12/24 VDC, to avoid the need for using an inverter as this takes a lot loss in the system. also switch your lighting system over to 12 VDC LED's. It's a lot of work but can be done, if it's thought through correctly. you'll probably need a small shed outside for all the batteries :)

You don't say if you will be off-grid or just want to be carbon-neutral or cost neutral?  That's key to your way ahead because, in addition to all the other good advice other members have provided here, don't overlook the fact that you'll be generating power off of your panels when you're out that you can feed into the grid and then draw some of it back out in the evening.  You'll pay more for your grid electricity that you get when you feed it in but the ongoing cost of that is quite likely to be cheap in comparison to the current high capital cost of batteries, invertors, Etc.  You can re-address that side of it as the cost of equipment eventually falls.


When calculating your loads, take into consideration that your high-load devices (washing machines, cookers, iron, etc) are running for a relatively small duration.  Change of lifestyle can also affect the end sum, e.g. we used to put the dishwasher on overnight, now we always put it on in the morning when the sun has fully risen onto our East-facing panels.  We also reduce our max load by running other high-load devices one at a time, example, boil kettle first then turn on grill for toast (or vice versa) so that we are making the most of our self-generated power and drawing as little as possible from the grid.  Also, regarding device load plates, they will always give you the worst case load that they are designed to cope with, e.g. items with pumps or motors are only drawing their worst case load in the first few seconds (or even milliseconds) of start-up phase before the load drops considerably but ovens, etc. will be slightly different.  All of that said, the best advice given above is that you will only get a fraction of your 4kw from 4kw of panels except on a small number of exceptionally few days when you have the sun perfectly orthogonal to your panels on a clear day


Finally, look at this website which contains a wealth of useful information including the available power at your given latitude, longitude and time of year. https://ec.europa.eu/jrc/en/pvgis Something I have found very interesting is the difference in power if you have actively trackiing solar panels instead of the usual fixed roof panels - it's about 50% higher.  Is it worth the additional cost of the panel tracking system?  That's something I'm working on!!