Uninterrupted Internet

Beat Load-shedding: Keep your internet & Wi-Fi on!

To keep your internet on, even when the power fails, you need a battery backup power supply unit and maybe a car charger. That’s it! Load shedding seems here to stay for at least a few more years. Not all of us can afford a generator or renewable energy installation to run our essentials in the house when load shedding hits us. Fortunately you do not require paying an arm and a leg to enjoy uninterrupted power for some of your low power and essential devices. I am a professional electrical engineer and I have shopped around and worked on finding the simplest, most affordable but reliable and safe solution. In this blog I describe an easy setup to keep your internet going, even when the power is off for 4 hours. This solution has been implemented and tested with great success at my self-catering guesthouse in Port Elizabeth | Umoya Cottages. So even when Eskom hits us with load-shedding, our guests still have lightning fast internet available.

If you have an ADSL router, all you need to keep the internet going, is to have a backup power supply connected to your router. Your ADSL service should not be interrupted since Telkom has UPS backups installed. You do get routers that even have fail over to 3G/4G, which is an extra bonus. I have a very simple entry level ADSL router without any 3G backup. This router works just fine for me. I have chosen a very simple solution, described below. But do be careful, if you swap your voltages around, you can destroy your expensive router. Work slowly and double check voltages with a multi-meter before you connect any power to the router! If you do not have knowledge of electricity, rather get someone to help you.

Step 1: What type of power do the router require?

This is simple. Check on the bottom of your router and it’s power supply for the following information:

  • Voltage
  • Amps
  • Polarity
  • AC or DC
Router Bottom
Power Adapter Bottom

Step 2: Get a good backup power supply

Batteries can be dangerous if used incorrectly! One can build your own battery backup power supply units (PSU), but it really is not necessary as these can be purchased for quite cheap. The battery backup PSU must have the following to ensure a good battery life and safety:

  • Overload protection
  • Good quality charging circuit
  • Under voltage protection
  • Automatic switching to battery when mains fails
  • Adjustable voltage regulator (Output)
Sherlotronics PSU
I suggest using the Intelligent PSU from Sherlotronics SA (Pty) LTD. They have an excellent unit that is of high quality and locally manufactured.

Step 3: Check if you need to convert voltages

If your router is 12V, then you are in luck. You simply need to cut the cable from the existing AC/DC power adapter and wire it into the output of the Intelligent PSU. Voila! Just make 100% sure that the polarity is correct by using a multimeter, otherwise you can destroy your router if it is swapped around! But not all routers or devices take 12V as input. Many require 9V or even 5V as input. My router for example requires 9VDC. You definitely CAN NOT wire a 12VDC unto 9VDC or 5VDC! You will easily destroy your device. So what is the best solution? You require a DC-DC voltage switching regulator to bring the voltage down to the correct voltage and allow enough amps to go through. You can purchase switching regulators like this one, but I have a much simpler suggestion. The easiest way is to purchase a car charger. They work out much cheaper and many are made to convert 12V to other lower voltages. Here is a good example from Communica. When purchasing a car (cigarette lighter) power adapter, keep the following in mind:

  • Output voltage of car adapter must be the same as input voltage of device
  • Max Amps of car adapter must be equal or more than Max Amps required by the device.
  • It is best to get a car adapter that uses a switching regulator (SMPS) instead of linear regulator. A switching regulator is more efficient and will allow your device to stay on for almost 20% longer.
Car Adapter

Step 4: Wire it up!

All that is left to do now, is to wire everything up, it should look something like this: Wired Up When the power goes out, the battery will automatically kick in and keep your internet going!