> When the power is out one cannot pay with cash either - because the cash register is offline. Cash registers can be connected to small UPSes to ride through

> When the power is out one cannot pay with cash either - because the cash register is offline. Cash registers can be connected to small UPSes to ride through smaller outages. You wouldn't need a larger battery if all you want to do is ride through a few-hour outage, or even a whole business day (8-12 hours?).