Depending on sensor power requirements, distance from star, etc., solar charging either takes a long time or require solar arrays large enough to make you easier to detect.

With its solar arrays fully extended the Dawn probe is 19.7 m (65 ft) long. The solar arrays have a total area of 36.4 m^2 (392 sq ft). That produces some 1900W, apparently, which is enough for the ~1.7m diameter antenna to get a signal back to Earth. Of course, the beam is pointed very precisely (no questions about "where is this thing coming out of jump?", the wavelength is very short to produce as tightly focused a beam as possible, and the receiver antenna on Earth is big. OTOH, I think that you're proposing putting the spysat much closer to the expected jump arrival point than Dawn is to the Earth. :)