Stay Connected Even When the Power Is Out

Your Spectrum Voice modem must be plugged into an electrical wall outlet to operate. Your Voice service (including access to 911 services) will be unavailable during a power outage without backup power, and may also be unavailable in the event of a network outage. In addition, moving your modem to a different address is prohibited by your Spectrum Voice agreement and will prevent an accurate emergency response if you call 911. If you would like to establish service at a new address, you must call Charter at (833) 267-6094.

Get a Battery Backup

  • To allow your modem to operate in the event of a power outage, you can purchase a battery backup directly from Charter. Our battery is available for a one-time charge. Once purchased, the battery becomes your property. You can order a battery backup when you set up new Spectrum Voice installation.
  • Customers who did not choose the battery backup or a battery-slotted modem at the time of ordering service can upgrade at any time by calling customer service. Existing customers will be charged a one-time standard fee for the professional installation. To order your backup battery and receive professional installation, please call customer service at (833) 267-6094.
  • You may also be able to purchase an Uninterruptible Power Supply (UPS) from a retail store. Contact an electronics retail store for more information.

Service Limitations

  • Spectrum offers two different types of batteries. One will provide 8 hours of standby power to your modem, the other will supply 24 hours of power. Please contact us to learn more about your options. Note: Battery time may be lower depending on battery age or if your modem is kept in a hot, cold or unclean environment.
  • A modem with a charged battery will power Spectrum Voice equipment to work with standard corded phones, but will not power other non-Charter equipment, like cordless phones or medical and security-monitoring systems.
  • To preserve battery life during a power outage, you should use your phone service sparingly and avoid using high-speed internet services.

Testing and Monitoring Your Battery

The images below show a sample modem. Battery indicator lights can vary based on the model of your modem.

You are responsible for monitoring the status of the back-up battery and for ensuring that the battery is charging normally. You should monitor the condition of your modem battery at least twice a year. Please note the following battery status light conditions after the unit has been connected and powered:

  • A solid light indicates that the battery is good.


Battery On


  • If the light is off, your battery has little or no remaining charge and needs to be replaced.


Battery Off



The back-up battery can safely be stored within the following temperature range: -4°F and 140°F.

Replacement and Warranty

If your battery is no longer keeping a charge, you can purchase a replacement from Spectrum or the modem's manufacturer. If you purchase your battery from Spectrum and it's defective, we'll replace it for up to one year from the date of purchase. The battery comes with a standard one-year-from-date-of-purchase warranty from the manufacturer.