Ah the good ol' days----
A note from experience..... If the meter reader/ smart meter? sees backfeed,
the utility is likely to ask questions. In my customers case, the Co-op was so
eager to prove to the Va. SCC that they were on top of net metering ( this was
the early days of net meter )--or maybe they just wanted experience with it,
they actually sent the Coop engineer and a lineman to the job to test shut off
with the grid off. This was with a Trace 6048 Power Panel., vintage 1999. The
lineman even put on gloves and face shield before we removed the covers so he
could verify no juice to the grid when we turned off the main breaker. Of
course nothing happened , except the house power stayed on, as the Trace
equipment was designed to sell back, but did not meet the new UL 1741
anti-islanding standard.
The engineer and the lineman were duly impressed~!
And the engineer approved the system for net meter ~!!
One more thing-- check that the utility meter installed records the sell
correctly--that is, doesn't count the backfeed as consumption. Around here the
new meters -- with remote reading capability--don't differentiate as to
direction--unless you sign up for net meter in which case you get the proper
meter.
We updated several Y2K systems to new UL certified inverters when the flooded
batteries had seen better days.
Sure don't miss all that watering/ equalizing/ and acid mist.
Just a few AGM's now--and an enlarged array.
Anyone need a 6048 Power Panel ?? off list please
Ken Schaal
CommonWealth Solar
Ashland, Va. 23005
804-216-5371
----- Original Message -----
From: Ray Walters
To: RE-wrenches
Sent: Monday, December 15, 2014 11:03 AM
Subject: Re: [RE-wrenches] RE;SW4024's were off grid, now on grid AC2
Controls?
What you want is already programmed into the inverter. It's called Low
Battery Transfer mode (LBX), its just a program setting on the inverter. You
select this mode in Menu 9, and then its actual battery voltage settings are in
Menu 16.
It will not sell back in this mode, but fromHome Power Magazine's Guerrilla
Solar movement of the 90s, all you have to do to sell back: "Don't ask, Don't
Tell, just press Sell".
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760On 12/15/2014 8:09 AM, Daniel Young wrote:
The way I would do this if using outback (really what I'm familiar with) is
to set up the aux relay on the inverter to trigger an AC relay that connected
the grid to the inverters ac input using the "load shed" function. It would
trigger the relay when the batteries reached a set voltage (user programmable
in the outback), then disconnect the grid at higher set voltage. Ex: activate
relay at 46V, then de-activate relay at 50V (48V system). All you are basically
doing is activating a charging source instead of severing a load to help the
battery state of charge. Not sure how the trace handles AC1 and AC2, so maybe
you'd need a second relay to make sure the generator input is always off when
the grid input is active.
Not sure if the trace has this functionality. Hope this applies, or helps
get you down the right path.
With Regards,
Daniel Young,
NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90
NABCEP Certified Solar Heating InstallerTM: Cert #SH031409-13
From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On
Behalf Of Dave
Sent: Sunday, December 14, 2014 8:10 PM
To: 'RE-wrenches'
Subject: [RE-wrenches] RE; SW4024's were off grid, now on grid AC2 Controls?
Here is a request for advice from one of my old off grid customers who has
recently brought in the grid to lessen his dependence on the generator. He is
NOT selling back to the grid.
The main question I have is this: Can we program the Trace SW4024 so that
that it will charge the batteries with Grid Power (AC2) when a low voltage
setting is reached?
<< "I have two SW4024 inverters. They are set up to each handle about 1/2
of the loads in the house.
Our system is setup so we are either on Grid power, or battery power.
The choice is controlled by a manual transfer switch.
AC1 on both inverters is backup generator which is controlled by Inverter
#1 when battery voltage reaches preset levels.
AC2 on both inverters is AC from the grid and is currently controlled by
circuit breakers. The circuit breakers are normally in the off position and
the batteries are charged by the sun. Typically if we want to charge the
batteries a bit with grid power we turn on the circuit breakers and the
batteries are charged through both inverters by utility power.
What I would like to be able to do is set the inverter, probably inverter
#1 for consistency, to allow grid charging at a set battery voltage and then
cut off the grid when it reaches an upper voltage. My thought is something
along the lines of, if the batteries reach 40% of full charge Grid is started
and allowed to charge batteries until they reach 80% charge.
I would like to continue as things are at present with the inverter
triggering the back-up generator if needed. Again my thought is at 35% of Full
charge Generator is started and is then shut off at 80% of full charge.
My goal is to use PV juice as much as possible with first backup being Grid
and second backup being Generator. This should allow us to go away and
hopefully run the house on PV but have two backups if needed". >>
I would appreciate advice from anyone with experience with a system like
this.
Best,
Dave
David Palumbo
Independent Power LLC
462 Solar Way Drive
Hyde Park, VT 05655
802-888-7194
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