<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Hi Luke</div><div>I am doing this with a 1200 watt array that is AC coupled to my off grid home inverter. I am using an SMA 1800 inverter because it is 120vac. I use a relay connected to the AC output that connects the 4500 watt water heating element to the AC breaker panel when battery voltage reaches the bulk setting. I use the auxiliary output of a Midnite charge controller to control the relay. Using a grid tie inverter is more efficient because the array is MPPTracked. Without the inverter an array connected to a water heating element, the array will spend a lot of time off of the. Maximum power point, especially n low light, and early and late in the day. Also the AC coupled array adds to battery charging when needed, before heating water. I see you point, that PV is so cheap, you could add an extra 1000 watts for the price of the inverter, but be careful what you used to disconnect 150+ volts DC. He temp switch on the water heater will arc and fail.</div><div>David Katz<br><br>Sent from my iPhone</div><div><br>On May 13, 2013, at 7:59 PM, "Luke Christy" <<a href="mailto:sgsrenewables@gmail.com">sgsrenewables@gmail.com</a>> wrote:<br><br></div><blockquote type="cite"><div><meta http-equiv="Content-Type" content="text/html charset=windows-1252">Hi Wrenches,<div>Now that the cost of modules has come down so much, has anyone out there experimented with solar <i>electric </i>water<i> </i>heating? As in: direct connecting a short series string of PV modules to a tank -style electric water heater with an element of an appropriate voltage and wattage rating…?</div><div> </div><div>A off-grid customer of mine who is also an electrical engineer has a situation that seems ideal for trying this idea out: he has a gas-fired tankless water heater and a water source that is very cold year-round. The idea is to take a 30 or 40 gal electric tank heater, switch out one of the the 240V elements to something like a 96VDC, 1000W element (difficult to find, but available), and direct connect 3 or 4 60-cell modules in series (with a disconnect and high-limit control of course). The tank would then serve to preheat the cold feed to the tankless heater. We think we can get a decent daily temperature rise with this setup. Probably not enough to heat the tank to a normal DHW temperature, but certainly enough to offset a good deal of propane consumption, and all for what I predict will be considerably less cost than a small solar thermal system.</div><div><br></div><div>Has anyone tried this? I'd appreciate any insights or opinions.</div><div><br></div><div><br></div><div>Thanks</div><div><div><div apple-content-edited="true">-Luke Christy</div><div apple-content-edited="true"><br>NABCEP Certified PV Installation Professional™: Certification #031409-25 <br>NABCEP Certified Solar Heating Installer™: Certification #ST032611-03 <br>CoSEIA Certified PV Installer <br><br>Solar Gain Services, LLC<br>PO Box 531<br>Monte Vista, CO. 81144<br><a href="mailto:SGSRenewables@Gmail.com">SGSRenewables@Gmail.com</a><br>719.588.3044<br><a href="http://www.sgsrenewables.com">www.sgsrenewables.com</a><br><br> <br><br><br><br><br><br><br></div><br></div></div></div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>List sponsored by Home Power magazine</span><br><span></span><br><span>List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a></span><br><span></span><br><span>Change email address & settings:</span><br><span><a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a></span><br><span></span><br><span>List-Archive: <a href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a></span><br><span></span><br><span>List rules & etiquette:</span><br><span><a href="http://www.re-wrenches.org/etiquette.htm">www.re-wrenches.org/etiquette.htm</a></span><br><span></span><br><span>Check out participant bios:</span><br><span><a href="http://www.members.re-wrenches.org">www.members.re-wrenches.org</a></span><br><span></span><br></div></blockquote></body></html>