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by rlpb 1114 days ago
While people are talking about use cases, I've been shopping for exactly this. My Nissan Leaf's DC-DC converter that drops the HV traction battery down to 12V (well, 14.6V-ish) to supply the regular vehicle electrics is apparently 1kW capable, as the heat pump needs a lot of power. If you turn the climate control off but leave the car on, then you can apparently pull 80A or so from the 12V "battery" perfectly fine as the DC-DC converter will keep it supplied. This is a relatively safer way of tapping into the traction battery without having to deal with the HVDC.

With an inverter, I could then supply (some subset of) my house from the traction battery, giving me a theoretical 18 hours at 1kW in my case (less efficiency losses).
2 comments
Faaak 1114 days ago
> as the heat pump needs a lot of power

I don't know about leaf's specifics, but most EVs have the heat pump / resistive element wired to the HV battery instead of the 12V one.

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rektide 1114 days ago
It's hard to imagine where one could safely pull 80a from. What kind of busbar that's exposed will have that available to safely draw from?
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rlpb 1114 days ago
From the main battery terminals, as far as I understand. I appreciate that this relies on the path from the DC-DC converter to the 12V battery to be sufficient for 80A sustained. Apparently this is fine, but I have yet to look myself.

An ICE car can have the battery supply ~200A through that cabling, though of course that's burst and not sustained. But it does suggest to me that it's not out of the question - especially as it's normal in the automotive industry for some cabling to carry such high currents for this reason.

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