Excellent idea. Grainger has a SPST "Relay in a Box" rated for 10-30V AC/DC and 10A. That should work great...
Jason Szumlanski Fafco Solar From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Mick Abraham Sent: Monday, January 31, 2011 9:43 AM To: RE-wrenches Subject: Re: [RE-wrenches] Photosensor for 12VDC System with load controller Maverick's suggestion would give the opposite action to what the original poster needs. The C12 "night light" function turns the load on after dark but Jason needs the opposite. The solar array can serve as your "photocell", Jason. The PV +/- terminals in the C12 controller have no power on them at nighttime (check me on that with your voltmeter), but they are energized when there is sunshine. A relay coil connected parallel to the the PV +/- terminals on the C12 should fire when the sun is up and that coil would then release at sundown. Use a "single pole single throw normally open" relay with a DC coil, and connect the positive leg of your DC load across the normally open connection screws. Make sure the relay coil can accept a wide range of DC input, since it may encounter 20 volts across a 36 cell PV module when the sun first comes up. Jolliness, Mick Abraham, Proprietor www.abrahamsolar.com Voice: 970-731-4675 On Mon, Jan 31, 2011 at 6:52 AM, Jason Szumlanski <ja...@fafcosolar.com> wrote: I have a customer with a Xantrex C12 charge controller with LVD controlling a 5A load. Their battery and PV are not large enough to run the load 24/7, and they don't need it to run at night. I am thinking about recommending a photocell to disconnect the load at dusk and turn it back on at dawn. They are not interested in upgrading the PV and battery (too costly). Can anyone recommend a photosensor source, and maybe a model number? Other ideas welcomed... Jason Szumlanski Fafco Solar _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@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
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