Having reduced your demand you are now in a better position to consider which devices you can’t do without during load shedding.
Being in South Africa we have a number of considerations that much of the world doesn’t have to deal with.
Whilst most of our security devices have battery backup these batteries were not designed for repeated full discharges and as a result fail prematurely. (See the section of Batteries the same considerations apply)
Criminals have become aware of this and use power outages as opportunities to ply their trade. It is important then that we provide for backup of such things as:
- Alarm Systems.
- Radio transmitters.
- Electric Fences.
- Gate Motors.
- Garage Door Openers.
- CCTV systems.
- Security Lights.
What household lighting will you want to run during backup?My answer is all of it. But not at the same time.
We have become very slack with our use of electricity and it is common certainly in my house to have many lights on all over the house and in rooms that are not occupied. With unlimited utility power this has not been a problem other than the complaints about the bill.
In a backup situation of whenever we need to generate of conserve power we will need to become more disciplined.
I advocate that, having changed to LED lighting, all light circuits be powered such that you can walk into any room and switch the light on. The caveat here is that you must switch it off when you leave or be plunged back into darkness prematurely.
Most of us like to sit and relax watching a bit of TV in the evening or maybe listening to some music.
So we need to provide for some but again not all of the following concurrently.
- DSTV decoder
- Music System
- Game console
- Phone Charger
- ADSL Router & Wifi.
Study & Work
Children in their Matric years or our young men and women at university will not be granted passes because they lost study time because of Eskom power outages.
Similarly many of us will require computer access during the evening to keep up with our work load.
It is imperative then that we also consider that some of us will need to provide for:
- Desk Top Computer
- Lap Top
- Phone Charger
- Internet Access.
Fridges & Freezers
For as long as power outages remain relatively short lived i.e no more than 4 hours we can expect our fridges and freezers to remain cold.
The need to provide backup for these will depend upon how much frozen food is at risk.
Fridges and Freezers are relatively high demand devices. The modern ones being less so but still requiring anything up to 100W.
Because of the fact that they employ pumps and compressors Pure Sine wave inverters are called for.
Provision should certainly be made to be able to include these items.
All of the above makes up our load and it will be different for all of us.
The next step is to enter a list of each and every appliance we wish to run onto the calculator. Here. (Link)
This will calculate how many watt hours of energy we must be able to supply.
From this we can calculate how many batteries we will need and deduce the maximum load which goes to inverter size.
This information will allow you to size and cost a suitable backup installation.