
• Generate your own energy from the sun • Reduce your electrical bills • Renewable energy • Low Maintenance Costs • Don’t let Loadshedding keep you in the dark
What type of system do I need for my house?
There are basically three types of solar systems:
- Grid-tied
- Hybrid
- Off-grid
Because of load-shedding we can add a fourth type but technically that does not fall under solar as it’s just a battery backup system (UPS) that keeps part (or all) of your house running off batteries during load shedding.
It does not make use of solar (sun) power and recharges the batteries when Eskom/municipal power is available again.
Grid-tied:
Uses solar (sun) power to supplement or run all power requirements for your house during the day. Can fluctuate because of clouds or rain. No batteries connected and therefore no storage of excess energy.
Hybrid:
Most common type used in houses. Uses solar power to run electrical requirements of the house during the day and also charges batteries with excess energy for storage and use at night when solar (sun) is not available.
Also uses Eskom/grid power for backup during days of bad weather or cases where battery storage is too small to run the complete house during the night and batteries run out.
Equipment can also feed back into Eskom/grid during the day when excess solar power is available (batteries fully charged and house electrical requirements less than available power from pv panels).
Off-grid:
No connection to Eskom/grid. Uses solar (sun) power to run all household electrical requirements plus extra for charging batteries for storage and use at night when solar power not available.
This requires a large solar panel bank as you need to compensate for bad weather and the duration thereof, as well as a large battery bank for storage. It usually also requires a backup generator or the possibility for grid connection. This can be a very costly system.
How many panels do I need to power my house?
You need to first determine how much power you use.
The best way would be to have a data logger installed to measure usage, but more importantly peak usage during the day and during the night. Y
ou can also work off your monthly (better yearly) bill which will give an indication of average usage per day.
When going solar, it’s also good practice to reduce your dependence on electrical appliances. Electrical geysers use a lot of power as well as stoves.
If possible, replace with alternatives like gas stoves or gas geysers or solar geysers. Replacing light bulbs with led bulbs can also significantly reduce power usage.
Are there any hidden costs associated with a solar installation?
If you are planning to sell excess power back to Eskom/municipality (not supported by all municipalities) you will have to have a smart meter installed at possible extra costs.
Also, solar inverters tend to push power back into the grid even when programmed not to. This happens for very short periods (seconds) usually when a stove or pump switches off.
This can cause the municipal meter to either switch off (as it sees the reverse power as tampering) or subtract units even though it is reverse power going back into the grid.
You might then end up not saving much on your electricity bill and to solve this you also need to install a smart meter at possible extra cost.
Why are Lithium batteries recommended instead of gel or deep-cycle batteries?
Lithium batteries are more or less double the price of deep cycle/gel batteries of the same capacity, but Lithium batteries have a 10 year guarantee, whereas deep-cycle/gel batteries only have a 3 year guarantee, which means you will have to replace them much quicker at extra cost.
Lithium batteries also charge faster and can be discharged more than deep-cycle/gel batteries.
For instance, if you have a 1 kWh Lithium battery it can be discharged to 80% whereas an equivalent 1kWh deep-cycle can only be discharged to 60%. This means that on a 1 kWh deep-cycle battery you only have 0.6kWh available for use whereas on the Lithium battery you have 0.8 kWh available.
Deep-cycle/gel batteries also take longer to fully charge.
What about super-capacitors?
Super-capacitors cost more or less double the price of Lithium batteries but they have more advantages.
They charge much faster, can be discharged completely, weigh much less and have a much longer life expectancy than Lithium batteries – (for instance 15 years compared to 10 years but expected to last easily 3 times longer).
