Powering OEM fan while Prius is off

Hey all,

I've taken a good look at my Enginer PHEV kit. It works great for my needs.

I usually charge the traction battery to 75% just by driving it around town. I'm using my old Plug-in Supply dashboard controller to send a CAN message to run the OEM fan at full speed while the vehicle is on. This allows me to keep the OEM battery temperature
relatively low while running the Enginer DC/DC converter.

If I charged my traction battery to 75%++ and decided to turn off the vehicle immediately, this is a recipe for thermal runaway.

I've recently started to park in a garage where the ambient temperature doesn't really change much(which, would probably allow the battery to stay at what ever temperature it is at for a very long time).

I've taken a look at the EAA-PHEV OEM fan control using a DPDT relay and a few other components(Prius OEM fan control - EAA-PHEV).

Would it be safe for me to just wire up a 12v power supply that is tied into my AC input line for the PHEV to the fan?

I already have a fan tied into the exhaust for the traction battery(it's being fed +12v), I could probably just parallel the OEM fan along with the 120VAC power supply in addition to a few diodes to make sure the fan or computer doesn't send power the wrong way.

What do you folks think?