Questions on the PW-3600 Solar Power Bank. Are there any advantages to using a second 7.2 volt NiMH battery pack in the solar panel? Is it intelligent enough to detect if one pack drops in voltage, the second pack will automatically power the camera? Or are they wired in parallel? Has anyone tried the 3600 with both battery packs installed? What are your results? Anything noticeable differences as far as uptime and possibly helping in partly full sun areas?