inputs.text: waht supposed - bought hobby project fit needs exactly seems capable delivering advertised step current without difficulty used conjunction circuit board failed battery tender junior failed transformer set able charge 12v starting battery 12 deep cycle battery charger drawing amp 18v boost convereter drawing 21 amps 80 efficient efficiency seems fall load charger dropped trickle mode boost converter still drawing almost 18 ampsthe reason didnt give five stars came no documentation information needed amazon item description would nice copy included item well vital facts using this1 input voltage must lower output voltage 12v input need set output least 125v2 output voltage cannot 3 times input voltage input 12v not set output greater 36v3 turn potentiometer brass screw head blue box clockwise increase output voltage counterclockwise decrease4 max continuous operating current must not exceed 3 amps description not clear operating assumption input currenthints get unit set safely1 use lower input voltage plan final installation example intend run 12v input use 5v input adjust output voltage reduce risk setting output less input2 use 5 amp fuse inline module input protect current