FAQ – UPS Systems

What is the difference between an UPS and a backup system?

An UPS supplies backup power and a backup power system can function as an UPS. But there are some key differences in functionality and what we define as a Backup system and as an UPS.

UPS Systems Backup power systems
  • Is typically small and portable in an enclosure.
  • Supplies power at one point through a multi-plug to certain devices.
  • Is not compatible with solar power.
  • Is limited to the amount of power can supplies, typically less than 3 kW.
  • Is permanently installed.
  • Is typically integrated into a buildings distribution board and provide backup power to certain circuits.
  • It is compatible with solar power and can intelligently manage the flow of energy between solar panels, batteries and a grid.
  • It’s not that limited to the amount of power can supply, one inverter can supply up to 15 kW.
  • How does one calculate what size UPS system one needs?

    One needs to calculate the total power consumption of all the devices together that you would like to run from the UPS.
    There are basically two ways to calculate the power and energy requirements of a UPS system.

    1. Install an energy logging device, this device will tell you the peak amount of power drawn at once, and the total energy consumed per day and per month. These devices are widely available to buy online, one good example is the Efergy Energy Logger.  https://greenenergysolutions.co.za/energy-meters/
    2. Download and complete our “Energy Usage Calculator” This can be completed and emailed back to us. Click here to download our “Energy Usage Calculator.

    How do I determine the energy usage of a specific appliance?

    There are 4 ways to determine the energy usage of an appliance.

    • Look at the nameplate on the appliance
    • Lookup the applicant model number on the manufacturer’s website.
    • Lookup the energy usage in the manual that came with the appliance.
    • Measure it with an energy meter or current meter.

    This PDF file lists the most common appliances and will give you an indication of typical energy ratings. Click here to download the PDF file,  GES appliances, typical energy usage

    Can I add solar panels to these UPS systems.

    Technically yes, but it is not recommended. To effectively make use of power generated by solar panels, the energy must be stored in the batteries during the day, and used at times when the sun is not shining. So the batteries need to be “cycled” each day. To make these UPS systems cost-effective, batteries are used that have up to 300 cycles. For solar application, one would typically use more expensive batteries with one thousand cycles or more at least. Lithium-Ion batteries can have up to 5000 cycles.

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