Was considering installing a second battery instead of a TCW backup battery given the use of the ULPower engine with dual electric fuel pumps and an electric engine controller. I was thinking about isolating the battery behind a solenoid and having a switch for “Aux Battery”. I would use this battery for the backup on the EFIS as well so no voltage drop with engine start, then engage the battery in flight to allow for charging. If one battery is the PC680 and the other is an EarthX, would this be a problem? Thanks in advance.