[RE-wrenches] Charge Control in AC coupled system

[solardude97]

We have done several of these systems with various inverter combinations. We used a voltage activated relay in the stone age to switch inverters between battery banks and the grid before the Trace SW came on scene. This little switch opens and closes a relay based on user adjustable set points. Just put a current carrying relay between the two inverters and use this unit to open and close it at your battery set points. You are simulating a power failure to the sell back inverter when the relay opens.
Contact me off list if you need one. I have cases of them, new and in the box. Still love the old SW's, even if they did cost me a fortune.
Nathan Jones
Power Source Solar
Springfield, MO
417-827-0738

On Thu Oct 28th, 2010 3:32 PM CDT Mark Dickson wrote:

>We have done one this way and came up with a good solution that has been
>working great for two years now.  However, this is proprietary information,
>so tough . . .!
>Just kidding. . .
>We used a Morningstar Relay driver to control 3 different "dump loads" that
>turn on at consecutively increasing battery voltages.  The fourth relay that
>kicks on is one that cuts the Outback's AC power to the Sunnyboys and shuts
>the solar down just in case the dump loads fail or if they are getting way
>more solar than they can utilize.  The dump loads that come on prior to this
>are various heaters and ice melt systems.  These dump loads work out great
>since the customers are only there in the summer and they rely on these
>heaters to keep their fancy home from freezing in the winter.
>
>Best regards,
> 
>Mark Dickson,
>NABCEP Certified Solar PV Installer T
>Oasis Montana Inc.
>
> 
>-----Original Message-----
>From: re-wrenches-bounces at lists.re-wrenches.org
>[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Howie
>Michaelson
>Sent: Thursday, October 28, 2010 2:00 PM
>To: RE-wrenches
>Subject: [RE-wrenches] Charge Control in AC coupled system
>
>Hi All,
>
>I have done several AC coupled off-grid systems using Sunny Islands and
>Sunny Boys, but I am now doing one with a dual stacked OB VFX3648 (with a
>PSX240 on the Inverter out for load balancing) and a SB3000.  There is
>also an existing array that is running through an MX60.  What I am
>wondering about is how folks have set up AC coupled string inverters to
>best utilize the solar gain while not toasting the batteries.  I'm a big
>fan of the tapering control offered by SMA through the frequency shift of
>the SI's, but that's not available here.  What relay/contactor setup have
>folks found most efficient and safe?  Thanks in advance,
>
>Howie
>-- 
>Howie Michaelson
>NABCEP Certified Solar PV InstallerT
>
>Sun Catcher, LLC
>Renewable Energy Systems Sales and Service
>VT Solar & Wind Incentive Program Partner
>http://www.SunCatcherVT.com
>(cell) 802-272-0004
>(home) 802-439-6096
>
>
>
>
>
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: RE-wrenches at lists.re-wrenches.org
>
>Options & settings:
>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
>List-Archive:
>http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>List rules & etiquette:
>www.re-wrenches.org/etiquette.htm
>
>Check out participant bios:
>www.members.re-wrenches.org
>
>
>
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: RE-wrenches at lists.re-wrenches.org
>
>Options & settings:
>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
>List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>List rules & etiquette:
>www.re-wrenches.org/etiquette.htm
>
>Check out participant bios:
>www.members.re-wrenches.org
>