The relay is built and ready, but I ran out of daylight before I could get it hung in the tree.
What I have is about 15" of 4" PVC pipe, capped at both ends to make a weathertight enclosure for the Mesh and V15 battery. A Voltaic 3.5 watt panel is zip-tied to the outside of the pipe, down low and out of the way of the Mesh unit. A pair of foam blocks, sourced from a PC power supply box, secure the Mesh and V15 in the tube and protect them incase the unit falls. The power cable from the solar panel enters through a weep hole in the bottom cap and is plugged into the V15.