Running a radiator from a PV panel

Hi - I have a studio in my garden, it is 3.5 m x 7.5 metres. It has electricity, but I want to keep it moderately warm (i.e. above  reezing) because I have computer equipment in it (for day time use I have an oil run radiator). A friend suggested a solar panel to  keep a small radiator ticking over. I don't have a huge budget, is this something I could do at a reasonable cost? Thanks. Sam.

 

Basically, no. It would be an extremely expensive way of providing heat!

Doing a few quick calculations on our solar panel calculator: a 500W electric heater (which isn't much), on for 4 hours a day, needs 3000Wh of electricity. Even in summer you would need 600 watts of solar panels - which would set you back about £3000. In winter, when you presumably need the heat, you would need an array five times as big.

If you've got electricity there already, you're far better off using mains for the heating - if you want to make savings, spend some money on improving the insulation!

Andy
Midsummer Energy

Sizing a solar panel for lighting a stable block

I am running two Lumina 18w lights in my stables powered from one 85amp leisure battery.  I am charging from the mains when the battery needs recharging.  Can you please advise what size & type of solar panel, regulator etc I would need to keep the battery charged.  I also run an electric fence from a second 85 amp leisure battery which is situated behind the stables.  Could I put the two batteries together, use one solar panel and run both applications? Regards, Wendy

Hi Wendy,

It all depends how many hours a day you use the lights! If we assume 1 hour a day every day, that's 18 watts x 2 lights x 1 hour, or 36 watt-hours per day that you need to generate from the panels. In summer you could generate that much power from a very small panel - even a 10W panel (such as perhaps the Spectra 10W panel, with a Sunguard regulator).

In the winter, you would need something bigger - but I think a 40W panel should be sufficient even in the depths of winter. In that case you would be best going for the 40W solar panel kit, which includes a 40W Kyocera panel and a Sunguard regulator, and all the wiring you need.

If you use the lights for more than one hour a day on average, you would need a bigger panel in proportion. If less than one hour, you can go smaller with your panel.

Yes, it would make a lot of sense to put the two batteries together and run both the electric fence and the lights from the one bank. Electric fences don't use much power - I think you would be able to run both the fence and the lights from a 40W panel. Very easy to do - you just wire the two batteries in parallel, with the two positive terminals joined by a lead, and the two negative terminals joined with another lead.

best wishes, Andy, Midsummer Energy

Solar and wind power for summerhouse

I have a summerhouse at the end of my garden and would like to power it with a combination of solar panels and wind turbine, hopefully through the same controller. I might want to use computer, stereo CD/radio,two lamps, perhaps 75w soldering iron - probably not all at once but possibly several at one time. Could you give me some idea what wattage solar panel, size of wind generator, and number of batteries I would need? Many thanks - Jenny

Hi Jenny,

A lot depends on just how often you want to use the equipment there! There is a world of difference between a big desktop computer and all the peripherals being used for a few hours a day, and a small laptop used occasionally for an hour or two.

You may find our solar panel calculator useful for working out how much power you would need.

However, a suitable system might include:

• Rutland 503 wind turbine
• Kyocera KC65 solar panel
• HRSi regulator
• 100Ah leisure battery (available from any motoring store, eg Halfords)
• 2 x Labcraft Trilite 16W lights
• 500W inverter (if you would like 240V power as well as 12V)

That would be sufficient for a few hours of lighting and radio use a day; and perhaps say an hour or so a day of laptop / soldering iron use (more in summer, less in winter).

One word of warning about wind turbines - the output does depend very much on the location. If you have many trees around that cause turbulence and restrict the free flow of wind to the turbine, you might be better off going for two solar panels instead!

If the summerhouse isn't used regularly - and mainly in summer - even a single solar panel may be enough for your needs. It is easy to add further panels, batteries, or a turbine to increase the system size when you want to expand the system in the future - so you can always start small and increase as necessary.

Do hope that helps.

Andy
Midsummer Energy

Lizard heating by solar power - is it practical?

Hi - I was wondering if you could help me, I'm looking to buy solar panels for my garden shed but don't know what one would be suitable. In the shed I have a glass tank with a lizard in it and I would need the panel to power an 80w fluorescent tube that is on 12 hours a day and a 190w ceremic heater bulb which is on 24 hours a day. Can you help? Cheers Andrew

Hi Andrew,

You can use the solar panel calculator to work out how big a solar panel array you would need. But I can tell you now that running a heater all the time would require a huge array unfortunately - 190W is a very big load to be powering for 24 hours a day. In fact I usually reckon that in the depths of winter you need a solar array with a rating of 20 times the average power draw of the equipment you want to power, as on cloudy days you don't get a big return from the panels. So, for a 190W continuous load, you would need about 3800W of solar panels - which would cost over £10000 and wouldn't fit on your shed roof anyway. Sorry!

If the ceramic heater is on a thermostat and is only actually on 10% of the time, that would make a huge difference - it would drop the array size to only 380W, which might just be practical.

Expensive lizard. Even on mains electricity you are burning about 5.5 kWh per day with that light on 12 hours a day and heater on continuously; at 13p per kWh that works out at over £250 per year.

Solar panels on garden shed

I know nothing about how to set up a solar panel system.  I am wanting to get power to a garden workshop to run a light, and power a plug socket for using small electrical equipment eg. soldering iron, drill. What products would you suggest would be suitable and how would I set them up?

Hi Jennifer,

A solar panel system is extremely simple - a solar panel charges a 12 volt battery (usually through a regulator, a little circuit that prevents the panel overcharging the battery), and then you can power your appliances off the battery. Many appliances are designed to run directly off 12 volts - anything that plugs in a car cigarette lighter socket for example - but you can also use an inverter to convert the 12V from the battery into 240V to power standard household appliances.

In your case you would need:
1) a solar panel kit (which includes the regulator and wiring) such as our 40W kyocera solar panel kit.
2)  standard 'leisure' battery, available from any motoring store
3)  a 12V light to run directly from the battery (eg the Labcraft Trilite),
4) an inverter such as the 500W model, in order to run 240V appliances such as power tools. For bigger tools you might need a bigger inverter - the 1000W model would be more than adequate for most household power tools.

The 40W solar panel kit should be adequate for occasional domestic use in a shed. If you were using the system for more than an hour or so a day on average you might need a bigger panel.

Do hope that helps. I know quite a number of people who have done similar things on their garden shed - it is pretty easy to set such a system up.

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).