Connecting solar panel into domestic electrical circuit

If I bought a solar panel to take abroad could I link it up directly to the
house electricity cables after the voltage meter?
Would this draw less power from the grid during the day?
Kindest regards, Saiduz.

Unfortunately it's not that simple! Solar panels produce DC electricity, usually at 12 volts, which is fine for battery charging. But it's not compatible with 240 volt AC mains electricity. You can use an inverter (eg the Silverline Inverters or Steca Inverters on our website)  to produce mains electricity from the battery that you have charged, but even then you can't simply plug that electricity straight into your mains circuit, as the frequencies they are running at will be slightly different and out of phase. Any equipment running off the inverter would have to be on a completely seperate circuit.

It is possible to get a type of inverter which can connect into your mains electricity. However these 'grid-connect' inverters are far more expensive, and only really suited to big arrays of solar panels.

How many solar panels to get 5kWh per day?

I am interested to find out more about calculating the amount of PV panels for my usage. It is around 1300KW a year with peaks around 5/6 a day. Is there a calculator that I could use to sort out what I would need?

Also are there any solar hot water panel and tank size calculations online?

many thanks, Tom

Hi Tom,

Have you looked at our solar panel calculator?

If you already know your energy usage you can skip the first couple of sections and go straight to part 3. If you put in 1000W of solar panels it will give you a rough idea of what you can expect from them per day: about 5000Wh (or 5kWh) in summer; 1000Wh (1kWh) in winter.

So, to get about 5 or 6 kWh in winter you would be looking at about 5000-6000 watts of panels. But it would be much easier in summer - you'd get the same return from just over 1000 W of panels.

Sorry, I don't know of a similar calculator for solar hot water systems.

Can I use a solar regulator to regulate a wind turbine?

Just having a look on your website for wind turbines and regulators etc. You suggest that you can connect up to 100W of solar panels into the wind turbine regulator in addition to the turbine itself.

Does this work the other way? ie. Can I plug a wind turbine into the solar regulator I already have?

I'm fairly sure the answer to this is no, from my memory of wind turbines they actually produce AC voltage by induction, is this still the case or do they now produce DC voltage direct?

Yours realising just how long ago it was that I last looked at electronics!!!

Neil

Hi Neil,

You're right that it's not a good idea using a solar regulator for a wind turbine - but it's for slightly more complicated reasons! Yes, turbines do produce AC by induction, although in fact it's normally rectified in the turbine itself so it's usually unsmoothed DC that comes down the wires. The problem is more to do with what happens when a regulator senses a battery is full. Most solar regulators will simply open circuit, which is fine for a solar panel. But an open-circuited wind turbine will spin freely, which is bad news in strong winds. So a turbine regulator is usually designed to short-circuit the turbine, which slows the blades down.

Also, solar regulators might not like the relatively spiky DC from the turbine compared to the very smooth DC from a solar panel.

Having said all that, you might get away with it in places that aren't too windy - but it's not really recommended by the professionals! You are likely to shorten the lifetime of your wind turbine.

Heating a garage by solar power?

I live in west wales and run on heating oil. Can you give me all the relevant info on solar for my home hot water systems and also electric systems.
Would the sticky panels work on a conservatory?
Also if I wanted to use a solar panel to give a large double garage heating would this work if the garage was in constant use?
Glynne.

Hi Glynne,

The flexible adhesive-backed panels should work on most surfaces which are big enough and flat enough - note that they are 3 metres long though, and they would probably not go over ridges very well, so it depends on the surface of your conservatory roof. To get the best results from solar panels it is important that they are angled south too, to get the most sunlight.

Note too that panels produce DC electricity, so you have two options - either use them to charge a battery, and run DC lights etc off that, or buy a grid-connect inverter, which allows you to connect the system into the national grid.

Hot water solar panels are generally used just for heating water for domestic use (washing, showers etc.) They aren't really a replacement for space heating, so no, I'm afraid you couldn't use them to heat your garage. The reason is that you get no output from your solar panels in the middle of cold dark winter nights - which is when you need the heating the most! For more information on solar hot water panels I'd recommend you try Navitron (www.navitron.org.uk).