Pic raced for Marussia in 2012 and the Banbury based team did not use the system last year.
"A good day and 109 laps today is a good way to finish the first test," he said.
"The track was colder this morning than the first three days so it was tricky getting the tyres to work, but we completed all the programs we’d set for the day and we have some very useful information to work on, and some interesting options to look at for the next test."
Pic was tenth on Day 4, but stressed that understanding KERS was more important.
"One key part of this test was to work on getting the most out of KERS and we’ve definitely made good progress on that. There’s still more to come from that, especially maximising its performance under braking, but I’m really happy with what we’ve worked through and can’t wait to get back in the car in Barcelona."