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Choosing and Powering the Electronics

A project log for Running Gigabit Internet between 100m to 5km

Documenting my project to get Gigabit internet speeds to my house which is greater than 100m away from the ISP

Peter McCloudPeter McCloud 12/02/2022 at 19:140 Comments

In the previous log, I laid out the reasons for choosing fiber optic cable for carrying the internet connection from the ISP to the house. This leaves the issue of powering the cable modem 700 ft (213 m) away from our house.

Running power that far leads to big expensive wires to deal with the voltage drop. Power from the utility company is available at the street, but the lines for our house are located elsewhere and a new power drop would have cost about $5000. On top of that, there's a minimum monthly charge of $15/month.

Given those costs, a solar power setup makes a lot more sense. In order to minimize the cost of the system, I wanted to choose electronics with low power requirements. I also knew that I wanted electronics that I could power directly from 12VDC to eliminate power losses involving an inverter.

The first item I needed was a cable modem. I wanted to support Gigabit speeds, but not have WiFi or any other features that would increase the power requirements. The cable modem I settled on was the Netgear CM2000. It's DOCSIS 3.1 capable, supporting speeds up to 2.5 Gpbs. It also had one of the lowest power requirements, which was 1.5 amps at 12VDC (18W).

The media converter was a bit harder to find. Turns out that most of the media converters converting 1 Gbps Ethernet to Fiber run on 5V DC. This could have been workable, but it would have meant adding extra electronics (and power) to set down to 5V.

There was one provider, FS, that had a media converter than could take 5-12V DC. It supports 1 Gbps and draws less than 3W.

The total required power draw then 21 Watts, so I needed a solar power system which is capable of providing 500 W/day, which isn't too bad (in actuality, the power draw is close to 12W, which only means 288 W/day)

However, I live in the Pacific Northwest and we get lots of cloudy days and snow, so I wanted a battery capable of providing powers for several days and panels that could charge the battery quickly when there's a break in the clouds.

I ended up going with a 200W solar power kit from Renogy, with a 40A capable charge controller in case I needed to add more panels (cause I have lots of trees and shade, which is a story for another time). For the battery I decided on a 12V 200 Ah battery, but if your in area with more consistent sunlight, you probably wouldn't need more than a 100 Ah battery.

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