How to Choose your PV System
How to know what to choose when you decide to go Solar. There are many options available and even more opinions on what you need to get. Here is an informed guide that will help you with your choice. These options took into consideration the South African environment (26deg Longitude, Climate and Ave 4,3 hours of solar generation per day).
Things to know and terminology. Grid-Tie means you generate power when the sun shines, generally do not have battery back-up, you go off when grid goes off, unless you have done some smart thing with transfer switches and so on. Grid-Tie is only a viable solution for some areas in CPT that allows for grid feedback.
Off-Grid means you have a battery backup, but generally you do not feed back onto the grid, but you can still use the grid to supply your system. Off-Grid does not mean you have to be 100% self-generating since you can use the grid to supply power where your system is not big enough yet.
Hybrid means you can have a battery backup as well as connect feed into the grid if you are allowed to. It is a nice to have, however you pay a bit more for the hybrid inverter.
For South African environment, the Off-Grid solution will fit most of the client’s needs the best. Critical Load means it is supplying power to you lights, and some plug outlets and excluded your geysers, pool pumps, ovens, and other large energy hungry appliances.
Option 1: I want to start with Solar, do it smart and not break the bank.
-Budget conscious
-Low initial capital outlay
-Increase system size in future seamlessly
-Reduce electricity cost
-Survive load shedding without a glitch
Solution for option 1: You choose the pace on upgrade frequency
| Stage 1 | Stage 2 | Stage 3 | Stage 4 | Stage 5 | Stage 6 | |
| Inverter (kW) | 5 | 5 | 10 | 10 | 15 | 15 |
| Solar PV (kWp) | 2,5 | 5 | 7,5 | 10 | 12,5 | 15 |
| Battery (kWh) | 5 | 10 | 15 | 20 | 25 | 30 |
| Estimated Cost (ZAR)/stage | R 55 470,00 | R 40 970,00 | R 110 940,00 | R 81 940,00 | R 166 410,00 | R 122 910,00 |
| Installation Cost @ 15% | R 8 320,50 | R 6 145,50 | R 16 641,00 | R 12 291,00 | R 24 961,50 | R 18 436,50 |
| Total Installed Cost (ZAR)/stage | R 63 790,50 | R 47 115,50 | R 127 581,00 | R 94 231,00 | R 191 371,50 | R 141 346,50 |
| Total Capital Invested (ZAR) | R 63 790,50 | R 110 906,00 | R 238 487,00 | R 332 718,00 | R 524 089,50 | R 665 436,00 |
| Self Generation Capable/year (kWh/year) | 3924 | 7848 | 11771 | 15695 | 19619 | 23543 |
| Monetary value @ ZAR 2.17/kWh (ZAR) | R 8 514,54 | R 17 029,08 | R 25 543,61 | R 34 058,15 | R 42 572,69 | R 51 087,23 |
Option 2: I just want WiFi to work when Eskom decides to switch off the lights
-Load Shedding is jumping on your last nerve with spiked shoes
-No Budget but will spend something not to fall over the dog in the dark
-Just want the Wifi to work so you can read the post from other that is in the dark
-Keep my beer cold, make some coffee and have the lights on.
Solution for option 2: Basically you want a UPS (Uninterruptable Power Supply)
| How much trust do you have in Eskom | Some | Maybe | Nope | Eish |
| Inverter (kW) | 5 | 10 | 15 | 15 |
| Solar PV (kWp) | 0 | 0 | 0 | 0 |
| Battery (kWh) | 5 | 10 | 15 | 45 |
| Cost (ZAR) | R 42 470,00 | R 84 940,00 | R 127 410,00 | R 295 230,00 |
Option 3: Let’s get it done, I am gatvol and since I cannot go on holiday this year again, I will spend my bonus on a complete solar solution that will bring me inner peace.
-Cost is a factor since I am not a politician, thus do not bankrupt me.
-I want the best at the best price, and no issues in a few years.
-I want complete system for my needs.
Solution for option 3: Complete Systems dependent on consumption
| Option 3: | Entry | Medium | Large |
| Inverter (kW) | 5 | 10 | 15 |
| Solar PV (kWp) | 5,5 | 11 | 16,5 |
| Battery (kWh) | 15 | 30 | 45 |
| Per Day Consumption (kWh/Day) | 23,65 | 47,3 | 70,95 |
| Estimated Cost (ZAR) | R 127 010,00 | R 254 020,00 | R 381 030,00 |
| Installation Cost @ 15% | R 19 051,50 | R 38 103,00 | R 57 154,50 |
| Total Installed Cost (ZAR) | R 146 061,50 | R 292 123,00 | R 438 184,50 |
| Self Generation Capable/year (kWh/year) | 8632 | 17265 | 25897 |
| Monetary value @ ZAR 2.17/kWh (ZAR/year) | R 18 731,98 | R 37 463,97 | R 56 195,95 |