UPS Runtime for Network Gear Calculator

When the lights go out in middle of a phone call, you’re worried. This will turn that concern into a number: specificaly, how many minutes of power you get before losing your WiFi network. Enter how many watts your switch and router consumes and it’ll give you an exact amount of time your internet connection remains active once electricity has gone out. Hope isn’t the goal; it’s about purchasing time.

The problem is that people tend to look at their UPS’s wattage capacity without considering its VA rating (most people use the latter). But watts represent real power and volt-amps is used to determine apparent power. A device with a very poor power factor might trip the wattage without tripping the VA limit, so what happens?

How to Calculate Your WiFi Backup Time

When you enter all of your equipment into the calculator, it convert between those two measures automatically. It then adds up total power draw of the router, modem, and any PoE-powered devices like cameras or access points. It then compares that number to the wattage and VA limits of your chosen UPS model. The lower of the two will dictate how long you have left.

A new battery isn’t the same as an old battery kept somewhere warm. A battery’s capacity drop with age and the tool makes allowances for that. After all, most tools don’t get a seven-amp hour battery that can actualy deliver that much when loaded up. The tool also accounts for the Peukert effect where higher current draws results in loss of actual capacity. Lead acid batteries suffer greater losses different than do lithium packs. You choose what type of battery you have (chemistry) and the tool will adjust for it.

Accounting for usable energy. It will help you determine whether a low-cost battery replacement are enough or if you should of go with something like lithium for longer run times. By reserving capacity, you give yourself a margin for error while also protecting against deeper discharges that could damage batteries over time. With that said, the calculator doesn’t factor in the unusable energy into its runtime calculation. This is where the reserve percentage come into play.

If you’re worried about protecting your equipment during a storm, use the calculator. And be sure to account for the right devices. Not everything in your office need to be backed up. Your desktop PC? Nah. Modem, router and NAS? Yes. Focus on the essential connection.

But many pieces of network gear draw far more then you might expect, like Wi-Fi access points that ramp up from six to fifteen watts once they has some clients connected. Cameras use even more, especially if they include infrared lights or motors. The reference table shows typical power use for common gear to help you figure out how much power you need to provide. (Nameplate ratings are worst case, and seldom seen.) For better accuracy, you can actualy measure what a device is drawing using a meter or smart plug.

You don’t want to run the internet on batteries forever instead of grid power. You just want it to be online until a storm passes, or a generator starts up again. Twenty minutes of battery backup will let you cleanly shut down rather than corrupting databases. Being sure of how much time you have takes away guessing. Instead of wondering if something will break, you’ll know when, which lets you make plans based off concrete information.

That certainty is worth way more then buying some additional battery capacity because you’re afraid.