Power protection for your POS: surge protectors and backups
What happens at your register when the power flickers for half a second? Without protection, the POS reboots mid-sale and you spend five minutes apologizing while it starts back up. A POS surge protector absorbs voltage spikes; a UPS, an uninterruptible power supply with a battery inside, bridges the gaps. A small store generally wants both, and neither is a big purchase.
Is a power strip the same as a surge protector?
No, and the difference is invisible from across the room. A plain power strip only adds outlets, passing every spike straight through to your equipment. A surge protector absorbs excess voltage, and its capacity is usually quoted in joules, a measure of how much surge energy it can soak up across its whole life. That "across its whole life" clause matters: the protection wears out silently as surges accumulate, and an exhausted protector still works fine as a power strip and protects nothing.
Models with a protection indicator light tell you when they're done. Treat a dark light as a replacement order, and consider retiring any protector that has ridden through a serious electrical event nearby.
What does a UPS actually do?
A UPS puts a battery between the wall and your equipment. When the power sags, blinks, or fails outright, the battery carries the load with no interruption your hardware notices. The goal at a store register isn't running for hours. It's riding through the two-second flickers that cause most reboots, and buying enough minutes in a real outage to finish the sale in front of you, settle the drawer, and shut everything down properly.
UPS capacity is quoted in VA and watts, but the practical spec is the runtime chart, which shows minutes of battery at a given load. Small units comfortably cover the modest load a one-register setup draws. Many also beep or log when they switch to battery, so flickers you'd otherwise never notice get counted instead of ignored, and after a few months that log tells you how dirty your power actually is.
How much backup does one register need?
Add up the load, hypothetically. A POS terminal, an idling receipt printer, and a modem and router together draw a modest number of watts, well within what entry-level units support. Against a load like that, a small unit's runtime chart typically shows enough minutes to finish transactions and shut down in good order, and often enough to keep the internet gear alive through a short neighborhood blip. Read the chart for the specific model rather than trusting a rule of thumb, because runtime falls quickly as load rises.
One sizing note: receipt printers print in short, power-hungry bursts. If your UPS is small, put the printer on the surge-only side and save the battery for the brains of the operation.
Where should each plug go?
Most UPS units split their outlets: half battery plus surge, half surge only. Battery side: the POS terminal, the payment device, and the modem and router, because keeping the internet alive is what keeps card payments possible during a blip. Surge-only side: the receipt printer and anything decorative. The cash drawer needs no outlet at all; it fires through the printer and opens manually with its key in a true outage.
Label the plugs while you're down there. Six identical black cords under a counter is a puzzle, and an outage is a bad time to solve it. The hardware all this protects lives in POS systems and card readers on NRS Marketplace.
Frequently asked questions
Do I really need a UPS if outages are rare here?
Full outages may be rare; sags and flickers aren't, and they cause most mid-sale reboots. A small UPS erases those events entirely. Weigh its one-time cost against a single evening of the register restarting in front of a line, and the decision usually settles itself.
How long will a UPS run my register?
That depends on the unit's capacity and your actual load, so the model's runtime chart is the only honest answer. The planning target is minutes, not hours: enough to finish the sale, settle the drawer, and shut down cleanly, with the modem alive through short blips.
When should surge protectors be replaced?
After any major electrical event nearby, whenever the protection indicator goes dark, and otherwise on age, since joule capacity depletes invisibly with every small surge absorbed. A protector that has spent years at a busy counter owes you nothing. Replace it and write the date on the new one.
Surge strips and replacement power accessories sit alongside the register gear in POS parts.