Want backup power? What to do

Want backup power?

What to do

In an excellent article in this edition, the writer argues that every electrical contractor should include a costing for a backup power system as an option every time they quote on a new job. But what about the existing home and retrofitting of such solutions?

We asked an experienced electrical contractor, Trevor Tappan, a member of the Highveld Region of the ECA, to share some tips with homeowners on the best way to implement a home electrical backup system, should they decide to do so.

Tappans Electrical (www.tappans.co.za) offers several services in the electrical trade. These include training, designing and consulting, and inspection and certificate of compliance certification and installations. The firm has considerable experience in fitting photovoltaic or electricity backup systems for the home, with a preference for using Freedomwon batteries and Longi photovoltaic (PV) panels.

A home UPS/electrical/inverter solution is installed mainly to provide emergency power during grid power outages and loadshedding. We asked Tappan:

What type of home UPS/power backup installation do you offer on a lower-end and also a higher-end budget?

We favour a system consisting of SAKO components, including a SAKO axpert type 5kw inverter with SAKO LiFePo4 battery (lithium battery). This installation costs around R65 000.

For those on a more expansive budget, we would suggest going partly off the grid by including roof-mounted PV panels, which would push the cost of the above system to R125 000.

What are supercaps?

A supercapacitor (SC), also called an ultracapacitor, is a high-capacity capacitor, but with lower voltage limits, that bridges the gap between electrolytic capacitors and rechargeable batteries. It typically stores 10 to 100 times more energy per unit volume or mass than electrolytic capacitors, can accept and deliver charge much faster than batteries, and tolerates many more charge and discharge cycles than rechargeable batteries (Wikipedia).

What does the (grid-tied) home UPS do exactly, and have your clients been pleased with the results?

A home backup/UPS system prevents spikes from the power utility and assists during load shedding by running select or essential services to the home depending on battery storage capability.

What kind of backup batteries are commonly used and do you have any advice on the higher end wall panel batteries?

We don’t install the Tesla wall-mounted battery but we do use the LifePo4 and sometimes consider using supercaps. A LifePO4 is an excellent Chinese-made lithium battery.

Is there anything you would like to advise the homeowner to do or NOT do?

• Make sure your chosen installer is registered with the Department of

Employment & Labour (DoEL) and has some training and understanding of solar PV systems (preferably also a member of the ECA). • Get references and make sure they are genuine, otherwise you could have a

‘disaster’. • Compare the components quoted on with datasheets that you will find on the internet; do some home research before taking the plunge.