DC to AC Inverter

Changes Battery Power to Mains Electricity

Once you're getting your solar panels to charge their electricity into storage batteries, you will probably want to turn that low voltage DC power into mains power for tools and household appliances such as TV set, Hi Fi stereo set and so on. That is what a DC to AC power inverter is for.

Most solar battery storage systems are 12 volts DC, though there are systems designed to store 24 volts and even 48 volts DC current. But 12v DC systems are the most popular, because so many accessories are designed for use in automobiles with 12 volt power.

If all you need is simple, low-powered DC lighting, you may be able to get by without a DC to AC inverter, but you're likely to want one as soon as you have enough solar panels and batteries to handle more serious electrical consumption.

In that case, your system's DC electric power will need to be fed into a DC to AC inverter. This changes the 12/24 or 48 volts DC into an AC voltage. (A.C. stands for Alternating Current — that's one which oscillates between being positive, then negative, then back positive again, and does this either 50 or 60 times every second.) Ideally this fluctuation is in a sine-wave pattern, but getting a good sine-wave inverter can be expensive, and not all equipment needs that pure a wave pattern. Different model inverters vary greatly in the quality of their output, so do your research dutifully.

Once your Direct Current (DC) electricity has been changed to Alternating Current (AC) electricity at the required number of cycles per second (Hertz), the inverter feeds the power through an electric transformer which boosts the voltage up to 110 volts or 240 volts, to suit your home appliances. You cannot just feed DC through a transformer because it doesn't change DC voltage... the transformer would just heat up and burn out!

The USA and Japan use 110 volts AC, while Europe, the UK, Australia and New Zealand use 220 or 240 volts AC mains). South Korea, I recently discovered, uses both 110 and 240 volt power standards in its modern hotels. Vietnam uses mainly 220v, but with both French-style and US type plugs. I have no idea what they use in Russia or the Eastern bloc countries.

Solar panels are not cheap, and you will need a lot of them - and a large bank of storage batteries — if your home solar system is going to run many appliances other than just basic home lighting. The electricity you buy from the power company is cheap, and we are all used to being able to consume lots of it for heavy-duty household appliances such as electric ovens, hot water heaters, dishwashers, refigerators, electric freezers, air conditioners, electric heaters — to name just a few.

Most home solar systems are not capable of handling these kinds of heavy load, so you will either have to have an absolute gargantual solar system, and a Bill Gates type budget, or else you will have to reduce your electric consumption to match the capablity of your solar panels and battery bank.

You need to write down a list of the lights and appliances you plan on running, find out how much energy each one uses. Then you should use a spreadsheet or chart to calculate the load on your circuits and battery system. Without this basic homework, it is unlikely your home solar system will cope with the demands you place upon it.