My camera detector won't work when plugged into my USB port, is there a problem with it?

When I plug a Snooper into the cigar lighter it works well, but if I use the USB outlet the Snooper screen shows a large USB logo but doesn't work. Is this because of a lack of power or is there a problem...

Do USB chargers drain your battery?

I recently purchased a USB adaptor that plugs into the cigarette lighter position. The adaptor has a digital display to show charging status. With the ignition switched off the digital display is still...