Battery Backup for Internet and VoIP

Battery backup systems have been around for some time, although mostly found in locations that provide emergency services, such as hospitals. Battery technology has continued to improve, with more power storage now achievable from smaller, more affordable units. While these units – generally priced between $50-200 – are not well suited for bigger appliances, they are perfect for powering broadband modems, WiFi routers, and VoIP phone service for a few hours (or more) during outages.

Jump to Section: Selecting a UPS Battery Backup Unit

Backup batteries for Internet modems (e.g. cable, DSL, fiber) and VoIP home phone service are becoming increasingly less expensive for consumers. While these units are certainly far from perfect, they often provide just the right amount of power to get the necessities done in a pinch.

Many cable or fiber Internet service providers will even provide a battery backup system inside of your home as part of your service. When your local ISP installs the box on the inside or outside of your home, it often contains a space for a backup battery pack. Unfortunately, most providers do not include the backup battery when they install the device, and many do not inform their customers that a battery backup option is even available.

UPS: An Uninterruptible Power Supply for Your Devices

UPS backup in home office

A home office setup with an APC brand UPS unit (far left) being used as battery backup for a home server, modem, and other networking devices. Image courtesy of Dennis Hamilton, via CC 2.0 Generic license

Battery backup devices begin working automatically when the power goes out. The basic function of these units is to provide power directly to your broadband modem, WiFi router, and similar devices when the power goes out, so that you remain connected, don’t lose data, and can continue to work even when the rest of your appliances stop working. While most of these units are not designed specifically for home phones and Internet modems and routers, their function best serves these types of devices.

When shopping for battery backup options, consumers will find several terms utilized, many of which refer to the same thing. The number one term to look for, however, is the acronym UPS. UPS stands for “uninterruptible power supply”. These backup battery units will often look like an oversized power strip. In a certain sense, this is exactly what they are. Unlike a typical power strip, these devices contain an internal battery that is charged while it is plugged in and powering your devices. When a power outage occurs, these devices automatically switch over to providing power from the internal battery to your devices, until the battery’s charge runs out. Many come with LCD screens that show the power level of the battery, as well as how much wattage is being drained once the battery kicks in.

For broadband modems and WiFi routers, this means that data transfers that were occurring at the outset of the power outage will continue. This also means that you can continue to make and receive calls over your VoIP phone service, provided the adapter is still getting power from the UPS backup. Of course, it’s important to note that and phone base (if the phone is cordless) needs to be getting power from the UPS as well. Laptop computers, tablets, and other mobile devices will continue to function as long as their internal batteries have power – although these too can be extended by plugging into the UPS or using a separate portable battery pack.

When considering a battery backup for home Internet or VoIP phone service, it is important to remember that internet connections can still stop functioning, even if your wireless modem and router are plugged into the battery backup. This is especially true for outages due to bad weather, where downed utility poles may be the cause of both power and Internet outages. Your cable or fiber provider may also have outages, or provide data intermittently/irregularly when the power outage is affecting a large area. So while your individual devices may still work inside your home, outside of your home there are a number of things that might cut you off from data services.

However, many consumers may have noticed that regular telephone services usually remain working even during a power outage. This is because phone companies provide the power for your phone through the actual copper wire in the phone line (this analog-based service, which is based on technology dating back over 100 years, is often called POTS, or “plain old telephone service”). Unfortunately, as mentioned earlier, modern cordless phones require external power in order to operate the base station. As such, when the power goes out, so do these types of phones. A battery backup system is a simple solution for this problem, since these phones rarely require much power anyway. Even the smallest, most limited battery backup supplies will provide enough power to keep the phone going for several hours. Alternatively, many people have maintained an “old fashioned” non-cordless phone in at least one room of their house as a backup.

Selecting a UPS Battery Backup Unit

Battery backups can be purchased in various sizes and offer a wide range of wattages. Although most of them will not provide much power to continuously operate a full desktop computer, cable modems and routers use a comparatively small amount of power. This means that, when paired with a wireless device that contains a charged battery, you can maintain access to the Internet for a much longer span of time. Depending on the total wattage stored in the battery backup, this could even mean several hours of Internet use after the power goes out – if you keep to your laptop, tablet, or similar device.

An entry-level battery backup (around $40-$70) will provide somewhere between 200-300 watts (~600VA). Wireless routers are solid-state devices that contain no moving parts, so they only pull around 6 watts per hour. Similarly, the average cable modem will also draw relatively little wattage, typically less than 10 watts per hour. If the power goes out, these devices could run on an entry-level battery backup for over 10 hours.


Mid-range UPS battery backups ($100-300) will generally provide between 600-1000 watts (~1500VA), which is usually enough to power a wireless modem and WiFi router for 8 hours or more.


High-end battery backups, which start around $1000, will often have with over 1000-2000+ watt capacities. Many, like the APC 3000VA Smart-UPS with SmartConnect are the rack-mount style systems used in offices and data centers. These units, which also begin to get extremely large and extremely heavy (some weighing 100+ pounds), are overkill for the average home user – although they could fit the bill for power users and home office environments.

Finding the right battery backup for your home is fully dependent on what you need to keep running. For broadband Internet modems and Ethernet devices, including voice over internet protocol (VoIP) adapters and WiFi routers, you’re going to need at least a low-end battery that can keep these devices running continuously for several hours. Thankfully, battery backups continue to decrease in price as they continue to improve in capacity and features.