Up, please!

I'm new to the CS 727. I installed the INS CIVA, everything is working well except that after 15 minutes, the battery light of my INS start to illuminate and then a few minutes after the INS shut down...

I use the infinite battery of FSUIPC, I also added the electric_always_available=1
in the electrical section of the aircraft.cfg but no matter what my battery still die....

Is there a way to solve that problem?

Thanks