Will do ? good! The exit is good. Be build DC to DC converter be 12VDC to 28VDC converter. By I uses the integrated circuit number LM2585 be pillar equipment for this work. Not difficult tell a lot of invite you see in circuit picture better.
http://www.circuitpowersupply.com/circuitblog/12v-to-28v-dc-converter-by-lm2585/