• What is an Inverter – in Layman’s terms

    To so many people, this is still a budding question. I’m certain that the majority of the population in South Africa are almost ashamed to admit that they do not know or understand what an Inverter is or what purpose it serves – hence, the fear of purchasing sets in.

    I will try to outline in a brief and understandable way what this device does and why it is so critical to own in this day and age. With Load shedding as real as it could be in our daily lives, an Inverter stands between you and your life being on hold for 2-3hrs at a time.

    First question I generally receive – Do I need a battery when I just want to buy an Inverter? Answer, Yes! Unfortunately the Inverter does not have the internal capacity to store power, that is what the batteries are used for. If you had to imagine the following layout: Power Outlet – Inverter – Battery. This is the simplest concept of having this solution installed into your household or office. During normal operations where ESKOM provides utility power, this sequence will ensure that your batteries are being charged (assuming that your Inverter has a built-in charger – not all of them do).

    Once Load shedding is implemented, the reverse effect will take place. Now your batteries will push power through the Inverter and a conversion from DC to AC power takes place. This basically means that the power stored in the battery now becomes safe to use for any appliance or electronic device.

    This can all be complicated a little further by adding solar panels to also charge your batteries, but we will get to that next time!!! I hope this has cleared up the question – What is an Inverter.

Want to go Solar without breaking the b­ank?

So, you’ve heard that “going solar” is going to cost you an arm and a leg?! 

Because of this, you have decided to let the idea go…

WAIT… STOP… You don’t have to go all Elon Musk on your first attempt.  There are more practical and achievable ways as well as a scalable approach to doing this, that could work out much more cost effective.

Let’s be real about this, not everyone can decide to go off the grid and NIKE it (Just do it 😊).  The key is to find a person or a company that will invest in you, as much as you will trust in them.  The initial step is to do your power consumption analysis.  From there you can start building on your plan and why not manage it as a project, by breaking it off into phases.  I would suggest that you do your planning based on financial budget and most urgent requirement.

For example – You can decide to make a large-scale investment every year around wintertime, when you receive your Tax return.  Year one, you potentially look at purchasing a 5kW Inverter (which is more than sufficient for an average household).  In addition to this, you purchase 4x 200Ah Deep Cycle Batteries.  So, this will carry you through load shedding, which will cover your lights, TV, WiFi, and even your fridge. Don’t worry, these few items will not mean you are at full capacity of what your Inverter can handle.  Dependant on a few factors, the above-mentioned items may put you anywhere between 30 – 45% of your Inverter’s capacity.

So now you are happy – No load shedding impact, but it doesn’t stop there.  In year two, you can now decide to add some solar panels (potentially enough to charge the batteries you already own).  Keeping in mind, this is all hypothetical at this stage (but close enough to be very indicative).  So now you purchase 12x 330w Solar Panels to carry some of the load of charging your batteries.  Please note, there is no exact science, as you need to take into consideration the number of hours direct sunlight your panels will get, cloudy days, the quality of the installation – were all the right gradients considered, etc.

One very important factor, that I probably should have mentioned earlier – please ensure that you make use of a certified electrician and/or an authorised installer for your solar panels.  You would require a CoC (Certificate of Conformance), due to the changes made to your home’s electrical wiring.

In year three and possibly year four, you can continue to expand on your battery bank as well as your solar panels to become more independent from the power grid.  With a combination between solar power and gas installations, you can save long term on your utility bill and become self-sustainable.

There would also be another alternative for homeowners, whereby you could take a loan against your existing home loan to assist with financing your off-grid solar project.  A rough cost estimation, as done in April 2020 would be as follows:

Phase 1 – R45k to R50k, dependant on the complexity of installation

Phase 2 – R35k to R40k, dependant on lay-out of solar panels and any additional installation requirements

Phase 3 & Phase 4 – Dependant on how you plan to expand ±R25k to R40k

**Costs indicative only

What is what when it comes to batteries?

What a good question…

Dependant on most Inverter’s Brand, Model and Size (rating), there are generally 2 options of batteries available.  It should either be a 12V or 48V battery, however certain inverters accept 24V output (what does this mean then?).

If you connect 4x 12V batteries in Series, they will remain at a 12V rating.  For example:

4x 12V 100Ah Batteries in Series, will still give you 12V output, but with 400Ah of battery backup (which means you get an extended runtime out of your batteries)

If you connect those same batteries in parallel, you could change them to a 48V configuration.  For example:

4x 12V 100Ah Batteries in Parallel, will give you 48V output, but still with only 100Ah of battery backup.

Then you can you also do both – WAIT, WHAT????

This means that you can add two batteries in parallel and add another two batteries to those in serial and you will have a 24V configuration.  For example:

2x 12V 100Ah Batteries in Parallel, will give you 24V output with 100Ah of battery backup.  Now take this existing configuration and add another two of the same batteries, but in series.  This will in effect give you the following:

2x 24V 200Ah Battery backup

Now I know this probably does not make sense to everyone, so we revert to pictures –

Both the Parallel and Series configuration
Battery in Series Configuration

So, carrying on from this, I go back to my previous statement, whereby you generally get two ratings of batteries – 12V and 48V.  Even though I have just explained to you how to achieve the 48V rating, there is also an alternative.  Most Lithium-Ion Batteries have a standard rating of 48V and then vary in size (rating), so, on your larger Inverter applications, generally from 5kW and upwards, the Lithium-Ion Battery is already compatible with the Inverter, with a single battery.  There are some suppliers that have 12V Lithium-Ion options available, but this becomes very expensive on smaller installations.

Getting back to the 12V batteries, which are the most used and known.  Yes, you can compare it you your car battery, but it is not exactly the same.  The Batteries used to store backup power are referred to as “Deep Cycle” or AGM batteries. 

The batteries used for cars are commonly referred to as “Starter Batteries”.  These batteries deliver a large burst of power for a short time as needed for normal engine starting. The battery is then recharged by the alternator. Unlike a deep-cycle battery, starting batteries are not designed to withstand multiple discharge/recharge cycles, and draining it can significantly shorten its life.

Deep Cycle batteries are designed to provide a steady amount of current over a long period of time. Deep-cycle batteries can be repeatedly discharged and recharged without causing damage or shortening their life. They are well suited to powering numerous electronics and plug-in accessories, or other applications that place high demands on them.

Starter Batteries would generally have a 3-5 year design life, which means that is the period you could expect it to last, before getting stuck one day.  There are external contributing factors when considering the life of a battery, for example: How you drive your car, The heat and weather conditions that you live in and how often you use your car, to name but a few.

The same goes for Deep Cycle batteries, there are generally two options available, either a 3-5 year design life or a 7-10 year design life.  Again, external factors come into play, mainly the ambient temperature in which the batteries operate, but the biggest factor would be how many cycles the battery is intended for.  Now you can think of a cycle as charging a completely dead battery to 100% then draining it to zero again.

Moving on to some battery terminology, how they confuse you and what they actually mean.  One of the most common battery naming conventions you will come across are VRLA batteries, simply put – Valve Regulated Lead Acid Battery.  From there we move on to Sealed Lead Acid (SLA) Battery, Absorbed Glass Matt (AGM) Batteries and we come to VRLA Gel Batteries.  The AGM and Gel batteries refer to an internal component within the battery that stores the electrolytes, used to charge the battery.

In my humble opinion, I think we have covered quite a lot in terms of batteries.  It may very well be that I confused you even more, but hopefully I was able to give a little bit more insight!

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