How soon will your solar system pay for itself?

Your Main Solar Energy Equipment Supplier

Welcome to MyPower(Pty)LTD, your one-stop-shop for all of your industrial energy needs.

From 2007 to 2020 we had an electricity tariff increase of around 460%. We pay now R2.69 per kWh in 2021, in 10 years it can be R10.88 per kWh if Eskom keeps on applying a 15% increase every year.

It is very clear that in future a lot of people will have to live without the luxury of electricity. If you are a young home owner it makes sense to invest in solar power. An investment in solar power will not only save you tons of money, but will increase the value of your property tremendously in the years to come.

A solar system can pay for itself in 2 to 4 years.

Important Basics to understand!

What is an inverter?

• It converts DC power to AC power
• DC (Direct Current) power is obtained from batteries and solar panels and the inverter converts it to AC power which you need to power your appliances etc.

An inverter is simply priced according to its abilities, but we need to understand the specifications.

Inverter types:

• Modified sine wave inverters (Small loads)
  1. Used in Small backup power units or small Mobile Solar power units
• Pure sine wave inverters
  1. Off the Grid inverters: These inverters needs a battery bank, they will convert the DC power to AC power while the solar panels or the Grid power charge the battery bank.
  2. Grid-Tie inverters: These inverters do not have a battery bank, they will use all the solar power possible and any excess solar power will be pushed into the grid. They are ideal for businesses where there maximum power consumption is during the day.
  3. Hybrid inverters: They offer the best of both worlds, they are actually Grid-tie inverters that can use a battery bank offering a more complete solution. These inverters will use the maximum amount of energy from the PV ray and battery bank and only use the difference from the grid if necessary. Then you can set them to use minimum or no power for charging the battery bank during the night.

Choosing the correct inverter for the job is a good starting point for a proper solar power system.

• Inverters do have some limitations in how much power they can deliver and they are normally rated in kilo Watts or KVA, for an example a 5KVA inverter can deliver 5000Watts of power. Some of our inverters can deliver more power when the ESKOM power is on, for example the 5KVA DEYE inverter do have a continuous AC passthrough of 35Amp or around 8000Watt while the power is on, but then will only be able to deliver 5500W when the power is off. With bigger load requirements inverters can be paralleled with each other, for example, 2 X 5KW inverters will give you 10KW.

We will discuss the system designing at a later stage. You will start to understand why the power consumption of your appliances are so important.

• What is Watts? (W)
  1. Watts is the amount of power something uses or can produce for consumption. Watts= Ampere x Volts

• What is kWh (Kilo Watt Hour) or the Units you pay for.
  1. A kilo stands for 1000, 1kW = 1000 Watts
  2. If you use 1000Watts for 1 hour then it will be 1kWh which is 1 unit on your electricity bill.
  3. The power consumption of each appliance is written on a sticker the back of the appliance.
  4. If a Microwave uses 1000Watts and you use it for 1 hour then you will consume 1kWh = 1 Unit

• How can we save on electricity consumption?
  1. A stove plate can easily consumes 2000Watts, if you use one plate for 1 hour then that will be 2kWh = 2 Units which is 2 X R2.69 = R5.38 per plate per hour. How can we save on this electrical consumption.
     1. Induction stoves are very energy efficient. They use 1200Watts on the highest setting and cook a lot faster than the conventional way. It doesn’t heat up the pot with an element, it uses an electromagnet that oscillates at a high frequency causing friction between the molecules which in result heats up the pot which makes them a lot faster to heat up a pot and they use a lot less electricity. There are no heat losses and is 60% more efficient than a conventional plate. Due to the fact that they are not so power hungry you will save on a lot more capital on the inverter choice due to a lighter load.
     2. Gas Stoves: The advantage of a gas stove is that it doesn’t use electricity at all which in return can have a bigger impact on how much power you will need from an inverter. A combination of a gas stove and an induction stove is a good idea since you will not know if there will ever be a gas shortage.
  2. A Solar geyser: Your standard geyser can easily use 3000Watts when it heats up your water. It takes around 2 hours to heat up your water which is 6kWh = R16.14. A solar geyser has got a much smaller element in when needed which is not so power hungry than a conventional geyser.
  3. LED Lighting: A 5 Watt LED globe give you the same amount of light than a 60Watt conventional globe or a 18Watt energy saver. Only 10 x 60Watt globes will consume 600Watts while 10 X 5Watt led lights will only consume 50 watts of power.
  4. Geyser timer: It is a proven fact that the cheaper geysers are not as well insulated and will cost you more on electrical consumption when left on. Only switch your geyser on 2 hours before bath time and off again afterwards. Rather use a kettle to boil water for dishes when needed.
  5. Power management: The “EFERGY” consumption meter is a very effective way to monitor your instant electricity consumption. This will make you very aware of electricity wastage and you will be able to download the data to your PC and understand your entire energy profile. You will need this data anyway to determine what solar system will be required to satisfy your needs.

• When choosing your solar system you need to take the following into consideration:
  1. The maximum amount of power that will be required at any given moment.
     1. Examples: Stove, each plate might use 2000W, Geyser = 3000Watt, Kettle = 2000 Watt,
     2. The Hybrid inverters can be paralleled with each other, for example 2 x 5KVA inverters will give you 10KVA.
     3. You can manage your immediate consumption with the Effergy meter. It is a wireless display monitor that displays your immediate energy consumption in Watts. Whenever you see that you are using almost using 5000Watts then you will know that you will have to start to manage your immediate consumption.
  1. 1. Maximum input from solar panels: a high maximum input voltage is important on saving on installation cost. The Watts input will simply indicate how many panels can be connected to the inverter.
        1. Mecer Hybrid II 5KVA: 4500Watt, 150-400VDC MPPT (MKS II)
        2. Growatt ES SPF 5000TL HVM: 6000Watt, 120-430VDC
        3. DEYE SUN-5K-SG01LP1: 6500Watt, 100-500VDC, MPPT x 2 (if you have 2 x MPPT modules then you can have 2 strings at different places on the roof maybe facing different directions. On one MPPT module all panels must face exactly the same direction.
     2. Maximum charging current: Important for big battery bank
  1. 1. Always use the exact same solar panels in a single string, do not mix and match, it will effect the power output on the entire string.
     2. Battery Choice:
        1. Gel Batteries: Gel batteries was an improvement on the Lead-Acid batteries in terms of life, with a depth of discharge Gel batteries has a life cycle of around 900 cycle versus 250 – 300 on Lead-Acid batteries.
        2. Lithium-Ion: They have around 6000 cycles on a DOD of 80%, a much better choice if you are looking for longevity, they will over time cost you a lot less, they take less space with intelligence built in.

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