Edit:
The 1.5 series Roadsters, 2008-2009, did not have a 12 volt battery, and the source of power for these devices was on of the first two sheets in the ESS pack, which ended up being a design problem since it unevenly wears out two sheets out of 11. By the 2.x series Roadsters, a 12 volt motorcycle battery was inserted fed by the output of a DC-DC converter which derived its power from all 11 sheets.
https://grubermotors.com/product/12-volt-battery-relocation-kit-2/