[ausev] Residental Solar Power ROI

[Brian Lasseter]

On Thu, Aug 7, 2008 at 1:30 PM,  <gregmckay at aol.com> wrote:
> How many AH could you get out of th EV's battery?
> Would you want to risk discharging too deeply?
> ....and then you have a vehicle that needs charging afterwards anyway....

In my personal case... The 18x 8V 170Ah batteries in my car store an
energy of 24.48kwh.  Of which, about half is usable.  I use 10-20kwh
in my house on an average day, so 12.24kwh would be more than enough
energy to get me through the night before the sun comes back up to
recharge the car.  (Especially since the Air Conditioning doesn't run
as much at night.)  Solar panels on the roof hooked up to a high
voltage electric vehicle power pack will keep you running for almost
forever.


> I know this is not a hybrid droup, BUT something like the Prius is perfect
> as a UPS backup.
>
> You hook an inverter to the 12v aux battery, fill the gas tank, and walk
> away.
> As you draw down the 12v battery through the use of the inverter, the car
> supplements the 12v with the HV battery.
> As the HV battery soc gets low the car is monitoring it and starts the ICE
> to recharge the HV battery,... and then the ICE turns off.
> ...and you can go like that until the gas tank empties....

A 10 gallon fuel tank has an energy equivalent of 345kwh of power, and
since the Prius will only let you pull 1500watts from the 12V side
before car stops supplementing the 12V battery, you could pull 1250W
with an inverter for 276 hours (or 11.5 days) before running out of
gas.  (Assuming perfect energy conversions... I don't know the
efficiencies of the Prius going from gasoline to engine to generator
to DC-DC converter to DC-AC inverter.)

However 1250W of power doesn't get you very far.  You could run a few
lights and a laptop.  You could run a microwave if you unplug the
lights and the laptop.  You wouldn't be able to run your fridge, or
the air conditioning.  You could not use it as a UPS backup for a
whole house.  One 15A circuit would be all I would trust it to run.

I run a 6656W solar system, and it can barely keep up if I'm at home
on the weekend with the air conditioning on, watching TV, and cooking
some lunch in the oven.


-- 
TTFN,
Brian "Lasso" Lasseter

"No Sane man will dance." -Cicero (106-43 B.C.)