Gigirolls

I've purchased a 2012 Chevy C4500 Duramax shuttle bus from the Madison County IL Transit Authority (MTA). Its in great condition. My question - it is a hybrid and there are two HUGE batteries strapped underneath. I've been trying to reach the MTA to speak with a mechanic about this but cannot reach anyone. Is anyone familiar with this setup? I would like to know what type if batteries they are and if I disconnect the hybrid, can I use those batteries for solar storage? Thanks!