Ok here is the how I have gotten to this point. I'm building a overland trailer. It is going to have a Optima Yellow Top in it for power. The idea is to hook it through an Anderson Plug to the FJs electrical system for charging. I'm trying to figure out if I need to run a DCDC charger. I need to know if the 2007 FJ uses a Fixed Voltage, Variable Voltage or Temperature Compensation Alternator. The Red Arc website pull down menu doesn't provide for the 2007-2010 FJs only the 2011-2016 FJ. (Redarc is a Australian company so the FJ was still available down under until 2016). The claim that the alternator for these rigs was a Temperature Compensation Alternator. Since mine is a US model and a 2007 I'm not sure if this is true for it also.....Any help would be grateful.