Project Power Supply

I'm not very familiar with power supplies but need to design one that fits my projects needs. I need it to supply three different voltages, 5v, 12v, and 24v. It also needs to have a "backup" battery so it go mobile at any moment. I need at least an amp for each, just to be safe. Any ideas?

Oh, one more question, should I isolate the power supply for each device even though they run on the same voltage?

Use three dc to dc SMPS boost/buck connected to a battery.

http://www.ebay.ca/sch/i.html?_odkw=dc+to+dc&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xdc+to+dc+boost+buck.TRS0&_nkw=dc+to+dc+boost+buck&_sacat=0

You have to calculate the battery capacity needed for your application and get a battery charger for it.
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So the line voltage goes to the battery charger, and the buck converters go to the battery?

Line powers the battery charger, connected to the battery, connected to three converters, O/Ps connected to your three loads.

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buck conversion from 24 to 12 or 5 is easy and cheap with LM2596 modules, which would
suggest a 24V system voltage - however that may impact battery cost. If any of the loads
are motors you will need to consider stall currents - most power supplies will shutdown on
current overload, which doesn't work with motors.