Editing Uninterruptible power supply (section)

===DC power===
A UPS designed for powering DC equipment is very similar to an online UPS, except that it does not need an output inverter. Also, if the UPS's battery voltage is matched with the voltage the device needs, the device's [[power supply]] will not be needed either. Since one or more power conversion steps are eliminated, this increases efficiency and run time.

Many systems used in telecommunications use an [[extra-low voltage]] "[[common battery]]" 48&nbsp;V DC power, because it has less restrictive safety regulations, such as being installed in conduit and junction boxes. DC has typically been the dominant power source for telecommunications, and AC has typically been the dominant source for computers and servers.

There has been much experimentation with 48&nbsp;V DC power for computer servers, in the hope of reducing the likelihood of failure and the cost of equipment. However, to supply the same amount of power, the current would be higher than an equivalent 115&nbsp;V or 230&nbsp;V circuit; greater current requires larger conductors or more energy lost as heat.

High voltage DC (380&nbsp;V) is finding use in some data center applications and allows for small power conductors, but is subject to the more complex electrical code rules for safe containment of high voltages.<ref>{{cite web|first1=My|last1=Ton|first2=Brian|last2=Fortenbery|first3=William|last3=Tschudi|url=http://hightech.lbl.gov/documents/DATA_CENTERS/DCDemoFinalReport.pdf|archive-url=https://web.archive.org/web/20101008075806/http://hightech.lbl.gov/documents/DATA_CENTERS/DCDemoFinalReport.pdf|url-status=dead|archive-date=2010-10-08|title=DC Power for Improved Data Center Efficiency|publisher=Lawrence Berkeley National Laboratory|date=January 2007}}</ref>

For lower power devices that run on 5&nbsp;V, some [[Battery charger#Power bank|portable battery banks]] can work as a UPS.