Why are you considering installing a system?

1/ because you want to go off grid?

Let’s have a look at the first option - Off grid.

From the little knowledge and experience I have gained in the past 5 years of working with these systems, it is literally impossible to go off grid, unless you live in a small room with no appliances, are prepared to spend a lot of money on a large inverter, lots of batteries and a roof full of panels.

The other option is to back up the systems using a generator; this has become a common practice.


2/ You want an uninterrupted power supply?

The second option has become a necessity in SA due to load shedding and the general lack of stable power. Some people just install an inverter and a battery, which will work if designed and setup correctly. Just be aware that if you are using FLA/gel or AGM, the battery setting and cut-out voltage is critical, get this wrong and your batteries will not survive a year. Temperature is a batteries worse enemy.

Something else you need to understand, unless you are on a time of use tariff and you setup your inverter to charge the batteries at specific times (off peak) and use the energy stored during Peak times, you will NOT save any money. I cannot understand why people are telling customer they will save money when they install an inverter and battery. I have even seen installations with solar panels, which are so badly designed that the customers lose money even with panels on the roof.

Something you need to understand, you have to charge the battery, If you decide to go with the cheaper option FLA, then the battery is gonna take a long time to charge and use a lot of electricity. The lithium will be faster depending on the battery charge rate, but still have to put the power back into the battery. While on this topic, for load shedding lithium is a better because of the charge rate. During stage 4 load shedding you want the battery to charge as fast as possible, so the C rating of the battery could become an important factor.



3/ You want to save money?

This is the difficult part, the only way to save money is to find a way to charge the battery that doesn’t cost and arm and a leg, you may think solar panels. You need to take into account the cost to buy, install and KWH production. If your electricity account is R1000 per month it will take forever to recover, then by the time you pay off the system, it might need to be replaced. Or newer better cheaper options will be available. Then there could also be tax rebates etc., which is apparently is being discussed in certain provinces.

Once again design and setup, get this wrong and you back to wasting money. Understanding the time of use is just as important as understanding the load requirements. Setup to optimise the sun hours is the key to a good long term solution. What you do with the power being produced by the sun is how you will determine the savings or losses.

It will require commitment from the entire household, shuffling the time tasks are carried out, Like the washing machine, don’t do washing at 7 am, or have your geyser timer set for 7pm to 9 pm and 3 am to 5 am. Don’t run your pool from 10 pm till 2 am. I am sure you already know this.

Someone mentioned a booster pump for their water system, if your system is designed correctly, and your gutters are catching all the water and you need to move the water to the low level tank to the tank at the top of the property, make sure you understand your load profile and program your control system to operate certain item at the correct time.

I am going to say this again, one size doesn’t suit everyone. You will only be able to optimize the system once it is installed and you have a way to view the charts and trends.