air con/heating 12V battery or main battery?
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Yes. While preheating my ZOE 52 in very cold weather SOC drops for ≈ 2 %.
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Are you sure?
I'd be surprised that they are running directly off 400v.
I assumed that the DC-DC converter was supply the energy to the 12v battery which then fed the HVAC.
Or is that what you meant?
No!. The electric compressor and electric heater runs directly off the traction pack voltage
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The fans and motors that control what path the air takes plus the HVAC control itself will be powered from the 12v DC-DC. Air compressor and heating will be from traction battery.
So the electrical loads are powered directly from the traction battery. QED.
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Obviously - where else is the power coming from - not the 12v battery as it is maintained by the DC-DC converter.
My surprise was to hear that 400v was supplied to the PTC and compressor.
One should not be surprised.A 5000W PTC heater would require 400 Amps, imagine the size of the cabling and the strain in the DC - DC converter😆
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Yes, I didn't think it through. 
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The 12v battery that is charged by the alternator which is driven by the petrol/diesel engine
The heating comes from the engine coolant and the Aircon compressor is usually mechanically driven by the engine too
Ultimately it is all coming from the petrol/diesel you put in, the engine creates electricity by turning the alternator and charging the small 12v battery for running lights/fans/displays etc. The heat is a byproduct of burning petrol/diesel and can be piped into the cabin via the coolant, air compressor is driven by the engine so also comes from the fuel you put in
We are on an EV forum yes???
The OPs question was framed on the basis of traction battery or ancillary 12v battery.
Sorry don't know of any BEVs that have an alternator.
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Read his question again. His question said petrol engines.
Sorry, DomJ is having a little conversation all on his own (apart from your company)
READ THE OPs ORIGINAL POST!
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I was quoting and responding to this post by OP... Technically off the topic of an EV forum but I don't see any harm in answering the question here
Not sure why you would conflate two separate posts. This thread, title and content of this original question clearly relate to BEVs. My reply was succinct and to the point, presumably answered the OPs question and dispelled any doubts.
No need to answer a different question which the OP had placed in a different thread, presumably because he knows the difference between a BEV and a Petrol Engineed car....Oh well
hey Freddy, looks like you're bit confused, I asked another question in THIS thread (few posts above)
Was trying to figure out where the power comes from in both Electric and Petrol cars.
Is this answering your question?hey Freddy, looks like you're bit confused, I asked another question in THIS thread (few posts above)
Was trying to figure out where the power comes from in both Electric and Petrol cars.
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You have overlooked some hybrids such as Honda Insight / CRZ which have a 1.5L engine( & probably others).
On these, the electric motor starts the engine and also charges the 12v battery via the DC-DC converter. There is no alternator.
On the Suzuki Swift 'Hybrid' there is only a starter/generator which looks like a large belt driven alternator. It starts the engine, provides minimal, if any assistance, and charges the battery. It's a waste of time apart from reducing the emissions and improving the mpg.
Also, why are you showing AC to the 12v battery on an ICE?
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