mercedes sprinter rear heat A/C off external power?

[wallyflint]

Is it possible to run the rear heater and air conditioner off of external power in a Mercedes Sprinter Passenger Van? If not, has anyone ever modified one of these to do that? Don't want to install another heater and air conditioner when it already has one!

 

[bullfrog !]

Most vehicle air conditioning systems use a compressor run by a belt off the engine and use quite a bit of power to run them. The heater usually uses engine coolant and the heat created by running the engine. Yes you already have a heater and air conditioner but they were most likely purpose built to be powered by the vehicles engine as it runs down the road. Some cars do have compressors driven by an electric motor but they are very uncommon I believe. Almost all use the engine coolant as a source of heat and the vehicle battery to run and control the blower fans and dampers. As stated before on this site some Prius owners run a 1500 watt inverter off the vehicle 12 volt battery as it’s charge is maintained by the big vehicle( 84 volt?) battery and can power a cheap 110 volt ceramic heater for several hours without starting the engine.

 

[afblangley]

I wish it was feasible to convert Sprinter's OEM HVAC to run on auxiliary power. Unfortunately, it is not. It is easier to replace or supplement the existing system. This topic has been addressed multiple times on the Sprinter-source forum. If you want details on why it can't be done, do a search there.

Heat is easy and cheap: install a diesel heater plumbed into the fuel tank. Most come from the factory with an auxiliary tap, specifically for that purpose. Installation is a half day job for those who are mechanically inclined. I have a cheap Chinese diesel heater under the front passenger seat. It can maintain a 75F interior temperature when it is 0F outside. In my build, it is more effective than the OEM heat ducts, which are partially obstructed by furniture. Power and fuel consumption are so minimal that they are non issues.

Air conditioning is a bit harder. The biggest issue is power: when the engine isn't running, how will it be powered? There are several options for auxiliary AC if the use case involves being connected to shore power. A solution that works with boondocking is doable, albeit expensive. If you haven't already, I suggest installing a rooftop fan and see if that is an adequate solution. There is at least one person on the Sprinter-source forum who removed the OEM rooftop AC and installed an RV AC in the opening.