Cutting through the BS for alternative power

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chrisc

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A very good friend is a retired marine electrical engineer and has been involved in substitute and alternative power supplies for many years.  He expressed concern at what he has been hearing from shops who purport to offer solutions to electricity blackouts, and ridiculous prices quoted for solar systems, some over R500k

He suggests the following

For the time being, while the load shedding varies between level 1 and 2, a simple inverter/charger/battery combo will be sufficient for your needs.  The size one you buy will depend on what you want to keep running, but on investigation with many households, an 800VA or 1200VA unit is more than adequate

Should the load shedding become more intense, then you can consider attaching solar panels, but the price will increment by a factor of 5 or more

Batteries are about 80% efficient.  In other words, to extract 100 a/h from a battery you have to pump in 120 a/h.  They also last between 4 and 6 years so must be considered a consumable item

A 24 volt or 48 volt battery conversion system is more efficient than a 12 volt system since the upward multiplication is a lot less.  Large power 12 volt transformers have a lot of wastage within the coils compared with a 24 or 48 volt unit.  Many inverters convert the DC straight to AC, then rely on a transformer to convert this to 220 volts.  The wasted energy will manifest itself as heat

Pure sine wave is much more desirable than modified sine wave, which can be a modified square wave or a trapezoidal wave

After much selection and consideration, he suggests components from this supplier in Somerset West

URL:  http://www.exsolar.co.za/products/

Look at Products / Inverter/chargers and True Sine wave inverters.  They have a sophisticated battery charger which will enhance the life of the battery.  One such unit was purchased in 2006 and still uses the original batteries (2 x 12 volt 40 a/h) after 9 years



There are obviously other equally good devices around, but these are recommended as being the correct device to fit the bill if you do not want to go the generator route and offer the most cost-effective way to provide alternative power at the moment





 
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