[aprssig] Tesla Field Day mode (or any EV/Hybrid)

[Robert Bruninga]

The idea in the Tesla or any other Hybrid or EV is to just draw 60 Hz
inverter power from the 12 volt battery system.  As long as the car is "on",
it will maintain the 12v system with up to 100 amps of current.  This is
enough to provide about a kW *average* to the House or Field Day for hours.
Peak loads are only limited by the size of your $100 inverter.

Though the national average is about 1 kW per hour per house, under
emergency conditions, I figure I only need about 250W for every light in the
house (now LEDs) and only about 250W while the refrigerator is running and
that is only half the time.

So, I guess that is what I was thinking.

Bob
-----Original Message-----
From: Greg D <ko6th.greg at gmail.com>
Sent: Wednesday, February 20, 2019 2:23 PM
To: Robert Bruninga <bruninga at usna.edu>
Cc: TAPR APRS Mailing List <aprssig at lists.tapr.org>
Subject: Re: [aprssig] Tesla Field Day mode

Hi Bob,

Yes, but the hard part is getting at that power.  The trick you used with
your Prius (aka PriUPS) is harder to do in modern EVs, given how the new
batteries have a much higher voltage and are well isolated.  You can't just
pull up the floor panel in the trunk and hook in with a pair of alligator
clips.

Just putting a ham radio in my EV was a challenge, since one can't pull much
power from the "accessory" outlet.  Mine is only rated to 8 amps, and most
mobile rigs can pull up to 13 amps.  In some cars, going direct to the
relatively small 12v battery isn't much better unless the car is on or
actively charging.  And if it's charging, well, you don't exactly need the
car...  I ended up going with a Yaesu FT-817, which has its own battery, and
recharges gently (under 3 amps) from the accessory port.  6 watts of RF
power to a glass-mount antenna is also unlikely to upset any of the car's
electronics.  Seems to work pretty well.

All that said, when a Tesla is in party or camper mode, I expect car is "on"
and the contactors engaged.  If so, it should be actively supplying
recharging power to the 12v battery derived from the main pack.  Under those
circumstances, you probably can get away with pulling a few hundred watts
from there on those cars.  It could be a good power source for emergency
digital communications (Winlink, APRS), but I seriously would not recommend
running your house from it.

Greg  KO6TH


Robert Bruninga wrote:
> Tesla is releasing Field-Day mode (er, "party mode") in its models to
> allow the vehicle to continue with AC/Heating, Temperature control,
> airflow, selective lights and music for up to 48 hours or more while
> in Park.  The feature will also allow users to power other electric
> devices using the electric car's battery.
>
> When  you think about it, the 75 kWh battery in the model 3 or the 60
> kWh of the Chevy Bolt can run the average American home at normal
> loads for about 3 days, or a week under power saving conditions.  With
> about $1000 or more of solar panels , you can have transportation and
> also maintain that Field Day forever. ;-)
>
> Just sayin...
>
> Bob, Wb4APR
>
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