kllcbosmetris said:
I'm trying to understand whether an 'electric motor' set up you mentioned can be implemented on a DIY camper van, in a way that you gain the ability to use your van A/C (re: some vans have rear A/C vents) set up -- which removes the need to have a roof-cut Maxx or Fantastic Fan. Would you mind elaborating on that possibility? Any type of alteration that can be done under the hood to create that 'use the built-in factory vents' option?
Okay, so you mainly want to be able to move air, not necessarily cool or heat it. As roof mounted fans only move air.
The ability to move air through the vents, is already done by electric motors in all the cars I have been in touch with. So to power the fan from a house battery, a switching relay is needed, that switches between getting power from the engine system or the house system, and you will be able to run that fan.
If there are air ducts way in the back of a van, then there might be a secondary fan where you need to add a similar switching relay to.
And if there are individual temperature zones in the car/van, then there are very likely a fan for moving air in each temperature zone.
But the principle to get air moving in the already installed vents, is the same: "Just" add a relay to switch powering those fans from the house battery.
It is however very likely that those air-duct fans, use much more power than the roof mounted fans.
In my last car the air-duct fan motor had its own 30 amp fuse.
I don't know the max amp draw of those roof mounted fans, but I expect them to be in the range of 4-6 amp at full blast.
Now, the car air-duct fans may not need to run full blast, so their effective power draw may be less (in the 6 to 12 amp range) , but they will typically draw quite a bit more power that the roof fans.
One reason being, that they have to push the air through all those turns and shapes of the air-ducts.
So though it may turnout to not be very practical (due to being too power hungry), that is the way I would run those car fans from a house battery.