On Tue, 10 Jun 2014 16:44:35 +0100, ss wrote:

I have been asked to attach a small solar charger panel for trickle
charger (maybe 6 inch square) thingy

Hum, I bought one with idea of it keeping the battery topped up on
the standby genset. Was connected for maybe 6 months, when I came to
use or maybe routine test the genset the battry was flat. After use I
left the panel disconected, similar time interval, battery fine...

OK to be fair the panel is in a NW facing window but it's little
light flashes... I guess the leakage through it when dark is not
being made up by the small amount of lecky generated during the day.

Silicone will stick it or one of the building adhesives, but will
leave silicone behind when it's removed. Stainless strip or even a
decently galvanized bit if steel withe the panal attached and pushed
up under a tile and hooked onto the batten will hold something that
small.

--
Cheers
Dave.