Dodge power cuts with solar-powered internet

2015-02-20 10:30 - Gareth van Zyl
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A basic solar powered kit that keeps a Joburg coder connected when power cuts hit. (Gareth van Zyl)

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Johannesburg - Load shedding doesn’t stop programmer and engineer Toby Kurien from carrying on with his coding work north of Johannesburg.

Kurien, who is an electronics engineer by background, has set up a basic solar power setup that keeps his internet router powered up and his laptop and phone charged when power cuts hit.

His setup is simple.

It consists of a solar panel, a sealed lead acid battery, a charge controller, cables and connectors and an inverter - all of which cost around R2 000.

The time savings Kurien experiences, though, is priceless as Eskom’s instruction to load shed can result in anywhere between two to four hour power cuts.

"I didn't actually do this for load shedding. I've been doing it for years because of lightning,” Kurien told Fin24.

"So, I don't like to leave my laptop plugged into the mains when there's a storm nearby because ... I've lost lots of equipment.

"But because I'm a freelancer - I work from home - I can't stop working every time there's a storm,” Kurien said.

Falling prices of solar panels prompted Kurien to put together his setup (pictured below).

When charged via a solar panel, the 12 Volt battery keeps the likes of his LTE wireless modem up and running.

The battery runs for up to eight hours while a charge controller manages the power load.

Fin24 witnessed his setup at work and our tech team even charged one of our smartphones using his setup.


Toby Kurien's solar power build which powers his laptop and internet router. (Gareth van Zyl)

"So, the difficult part becomes just wiring it together which is literally a screw driver. If you can wire an alarm panel for example, then you can do this. It's actually much simpler obviously. You just hook up the battery where it tells you to hook it up; it comes with a manual,” Kurien told Fin24.

"There's no soldering or anything like that; you're just putting wires into terminals,” he said.

Kurien, though, offers a word of caution when connecting a router as uses a voltmeter to check that his router won't get damaged.

"You would want to be careful when you plug it into your router; you wouldn't want to get that wrong,” he told Fin24.

As a disclaimer, readers should be aware that connecting the wires incorrectly can cause equipment damage. Kurien also said that using wires that are too thin can cause them to heat up. (If in doubt, consult experts about this setup then.)

The setup that Kurien uses consists of the following components which you can buy from electronic stores such as Communica or Bush Power. Kurien said Chinese electronics stores in SA can also provide good deals on equipment such as solar panels.

This system is ideal for powering low wattage devices, such as a router and phone:

Solar panel – 50W: R485

Charge controller – Steca Solsum 6.6F 6A: R275

Battery – 18Ah Rechargeable Lead Acid: R421

Inverter -Mean Well 300W Modified sine wave: R710

The inverter can be used to power AC devices such as a laptop. This will place an additional drain on the battery though. But a fully charged laptop battery means you can choose to make the inverter an optional add-on. Also, cables and connectors could set you back around R20.

Below is a diagram and example calculations on what you need to consider for such a system.


A diagram detailing the layout of this solar kit. (Gareth van Zyl)

Calculations

To power the likes of an internet router, Kurien’s setup can easily handle it.

A typical 12 Volt, 1 Amp internet router, for example, draws 12 Watt hour (Wh) (Volt X Amp = Watt X Hour = Watt hour) and 48 Wh over four hours.

“Technically, this is very conservative. The 1 Amp figure is for the power supply, meaning the router typically draws a lot less. I measured my router, and it only draws 0.2 Amps on average, which equates to 2.4Wh,” Kurien told Fin24.

An 18Ah, 12V battery then - like that of Kurien’s - is capable of powering this router alone.

Kurien said it’s wise to typically only drain 50% of the battery when using it to avoid severely shortening it's life span. As a result, using this calculation can assist with working out your battery’s capacity: 18Ah x 12V = 216 Watt hour X 0.5 = 108 Wh

To work out the energy your panel can supply to the battery, multiply Watts by the hours exposed to sunshine, then multiply the result by 0.85 (for natural system losses).

Example: A solar 50W panel in 4 hours of sunshine, 50 x 4 x 0.85 = 170 Watt Hour. This is the amount of energy the solar panel can supply to the battery.

Other options

To keep your internet on during power cuts, you don’t necessarily need to build your own solar system.

A Kenyan made 5.18 inch device called the BRCK can keep you online even when the lights go out or 3G signals drop.

Its features include an eight hour battery life, 3G and LAN network capabilities and Wi-Fi capabilities.

It started out as a project on crowdfunding website Kickstarter and has since sprung into full production as a device that can be bought online for $249.99.


The BRCK, an African made device that can connect to the internet when power cuts hit. (BRCK)

Nairobi based Erik Hersman, who founded Nairobi’s iHub and emergency crowdsourcing software Ushahidi, is also part of the team behind BRCK.

“While we don’t have a distributor in SA yet, you can buy the BRCK online on our store and we’ll ship it to you,” Hersman told Fin24.  

“There’s no doubt that for the technically non-literate, the BRCK is a good solution that you don’t need to worry about wiring up.  Just buy a SIM card and you’re on your way.  It’s battery will last up to 8 hours, likely outlasting your laptop’s battery, and you can add an antenna to the device to extend your range for using the wireless signal,” he said.

South Africa’s power cuts have started to bite this year, but a country like Kenya also grapples with electricity shortages.

On January 16, half of Kenya was hit by a blackout which knocked out power supply for several hours.

The East African country, like South Africa, has a sole power distributor in the form of Kenya Power.

Hersman added that a solar powered setup, like that of Kurien’s, is something that Kenyans also put together.  

“Kurien is a guy after our own hearts, this is just what we would do in the same situation.  Many of us have solar and UPS (Uninterrupted Power Supply) solutions of our own, and having a company full of electrical, RF and software engineers means we design and build for the problems - like this - that affect us,” said Hersman.  

“You know, the reason we built the BRCK was because we were tired of power outages resetting our router,” he added.

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