Problem with power supply and synthesis bench

[Puskai]

So I have this weird thing happening with my synthesis benches.
If I connect 1 synthesis (6w draw) to my solar panel (15 w output) it works and when I check the solar panel it says 6w out of 15w are used. As it should be.
When I connect a second synthesis bench, the solar panel shows 12w used out of 15. The math checks out 15-2x6 again ,but now both synthesis benches show "insufficient power". Any ideas ?