For my Roof top Solar Mesh Routers, I originally used 10,000 mAH Li-Po and a small Li-Po charging bag (fire-proof). The bag was wrapped with Mineral Wool Insulation. A TMP36 was placed inside the bag to monitor Li-Po Temperature. Of course, everything was placed inside a weatherproof enclosure.
But, I had a Mesh Router sucked-up and blown off the roof during a high wind storm.
The design eventually migrated to a 12V SLA battery and box since I needed the weight (from the SLA) for this application, and physical size wasn't a design constraint.
In my experience, it's harder to keep the moisture out of the enclosure verses managing the internal temperature. Eventually, moisture finds it's way in with the extreme temperature swings that we see in the Southern USA 
.