Is there such thing as a portable power supply?

Most of the time, people will have or rent a small generator for these types of applications. This is one of their main uses. Set it off a ways and use an extension cord to keep the noise down, but most of them are pretty quiet anyway.

A power supply is a circuit section designed to convert the common, available line voltage supplied to homes and businesses into the lower, exact DC voltages (and occasionally some other AC voltage) necessary to operate the rest of the equipment.

If your equipment is designed to run solely on a DC voltage from the power supply, then your 'portable' option is to use batteries as that DC source. The number of batteries would be a function of the necessary voltage, as well as expected duration of the batteries under load.

A UPS (Uninterruptible Power Supply) is nothing more than a relay which provides your AC line voltage to your equipment, and in the event of power failure, drops the relay to switch in large batteries to continue supplying power for a limited time. Also, it recharges the batteries when line power is available.

So, even with a UPS, you're back to.... batteries.

What you are looking for is called a UPS. An uninterruptable powel supply. They are used to protect computers from power outages. They start from $50 and the sky is the limit.

Fo ryour purposes you might need at least a $200 one, depending on how much power you will use in that 45 min.

eg http://www.staples.com/webapp/wcs/stores/servlet/S...

CAUTION!!! Some of these battery backups, even thou they use a battery to generate 110V it might need to be plugged in to operate for grounding purposes. So test it without being plugged in, and if it doesnt operate return it.

If you are short on cash. Buy an inverter with a suitable wattage for your needs. (those in car 12V to 110V makers) hook it up to a charged car batter or preferable a deep cycle battery(car batteries dont like to be completely discharged). Make a pretty box to hide the mess in :P

on account that a generator is out approximately your merely selection would be to hold an inverter and vast battery. we are speaking vehicle battery length, in case you go with the home equipment to run for every time in any respect.