Cdni3 wrote:Does anyone know if it is possible to either put a second 12V battery (deep cycle battery) to run a 12V ARB cooler/freezer (2.4 amp draw) for an extended period of time and have it charge from the main EV battery? Does the REX charge the 12V battery along with the main EV battery?
The 12V battery is charged by the high-voltage battery pack via a DC-DC converter that reduces the high-voltage down to ~14V, but only when the car is in the Ready state or is being charged. So running your cooler/freezer with the car off would discharge the 12V battery.
To the 12V system, adding a second 12V battery in parallel with the existing battery would appear the same as if a single much larger capacity 12V battery had been added. Generally, 12V systems aren't sensitive to different battery capacities. However, if your cooler/freezer discharged the 12V batteries too much, the car would not be able to enter Ready state which could strand you. If you connected the auxiliary battery with a switch that could isolate it from the standard battery, you could discharge the auxiliary battery without also discharging the standard battery which would prevent being stranded. However, reconnecting a very discharged auxiliary battery to the standard battery could cause the voltage of the 12V system to suddenly drop and a high current to flow from the higher voltage standard battery to the discharged auxiliary battery, both of which might cause problems. Others with more electrical knowledge will likely comment.
The REx generator charges the high-voltage battery pack, not the 12V battery directly.