A GT inverter is not a voltage source able to supply power to a load.  It is
a CURRENT source that pushes an MPPT derived amount  of power in phase with
an existing waveform that is connected to a near ZERO IMPEDANCE load (the
grid).  Withtout the grid, even if you fool it with a  waveform, the voltage
would soar to extremely high voltages when the load is not there.

And until the EVSE has concluded its dance with the car, the load is not
there.  Adding kludge onto kludge to make this work is not viable.

So it needs to be a common power inverter, that is fed HV DC to match its
output xwitching circuit to deliver 60 Hz AC at 1500W for a standard EVSE.

Actuaslly, I guess it is worth going to the full 16 amps allowed for 120v so
probably starting with a 2 kW inverter would be worth doing.

The goal is something that fits in a box, about the size of a standard 120
VAC inverter than can be on hand to "clip" onto a solar array in an outage
to provide EV charging.

Bob


-----Original Message-----
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Matt Lacey via EV
Sent: Friday, October 06, 2017 4:33 PM
To: Cor van de Water via EV
Cc: Matt Lacey
Subject: Re: [EVDL] Solar Emergency Charging

You could get a 120vac grid tie inverter. Those typically have a mppt front
end that boosts or bucks to a nominal 180vdc before inverting to 120vac.

Connect the two 180v dc buses and you're good to go.

Having a bit of storage capacity on that dc bus would be ideal for starting
loads

⁣Sent from BlueMail

On 6 Oct 2017 21:39, at 21:39, Robert Bruninga via EV <ev@lists.evdl.org>
wrote:
>I want to develop a way to charge an EV from a Solar array when the
>grid is down cheaply.
>
>My thiking is that typical modified sine 12v/120VAC inverters do their
>inversion first from 12VDC to high voltage DC first, and then they chop
>it to make it modified sine.
>
>If that is the case, it should be possible to inject high votage DC
>from the solar panels at that same point and produce the same 120VAC.
>This then can drive any standard 120v EVSE.
>
>We can tap into solar panels in increments of 30 VDC and should find
>one close.  The problem will be the starting process to bring the VOC
>down to the Vmax that matches the HV in the inverter..  That can be
>done with a trivial big resistive load a few caps and then transfer
>relay maybe.
>
>Thoughts?
>Bob
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