[amsat-bb] Tesla Field Day mode

[Zach Metzinger]

On 02/20/19 16:41, Frank Karnauskas wrote:
> I think Mr. Bruninga published an article in QST or CQ a few years ago
> about the advantages of using a vehicle instead of a separate gasoline
> powered generator for emergency uses?

It is, perhaps, a convenience to go this route. However, in terms of 
efficiency, small generators win every time.

Just think about all the systems your car is running (fluids being 
pumped around, electrical loads) and the fact that a gasoline engine at 
idle has terrible thermodynamic efficiency. Quoting a 2008 paper[1] by Remy:

> With a typical engine efficiency of 40%, a belt efficiency of 98% and
> an alternator efficiency of 55%, this leads to an overall energy 
> conversion efficiency of only 21%. Assuming a fuel cost of
> $4.00/gal, this leads to an on-board electrical power cost of
> $0.51/kWh, or roughly 4 times a typical household utility rate.
Now, that's just the alternator, discounting all of the other stuff 
bolted to the engine. Compare this to my back-of-the-napkin calculation 
of $0.70/kWh for the EU2200i at max rated load[2]. The car seems like a 
win, but it won't be due to the "other stuff" eating energy.

I can attest to the quietness of the EU2200i, as I own one. However, a 
solar panel is even quieter. :-)

--- Zach
N0ZGO

[1] http://www.delcoremy.com/documents/high-efficiency-white-paper.aspx
[2] https://powerequipment.honda.com/generators/models/eu2200i