I am running 1.8.9 experimental.
I crafted a solar helmet. I put it on. I put on a partly depleted jetpack. I was fully exposed to the sun in daylight. The jetpack did not charge. 30k power should take 25 minutes to charge, but I should go from 27.7k to 27.8k in 5 seconds assuming 20 EU/second.
It also did not work with a Bat-Pack.
Tried restarting the game, removing each equipment and putting it back on.