I am glad you found what you were looking for Jim. The discussion made me more confused. According to what I understood of the theory behind solar panels, they can operate in parallel and both will contribute as a power source as long as the voltage is within a range (ie: below OCV Open Circuit Voltage) It is (was) my understanding that the panel delivered the maximum output power when it is clamped at a specified voltage and it delivered less than the maximum power (ie:70-95%) when operated inside a range of voltages. The smart controller operated the panel at the sweet spot voltage where the panel delivered maximum power and shifted the operating point as the sweet spot moved around due to shading or whatever. Having said that, I am not going to dispute anyone who performed testing and documented the theory is false. (I haven't done any testing with panels operating in parallel) As Mohandas Gandhi said : Truth alone will endure; all the rest will be swept away before the tide of time. All the best Ahmet S/V 8827
> Date: Mon, 6 Apr 2009 05:30:51 -0400 > From: [email protected] > To: [email protected] > Subject: Re: [Liveaboard] Solar charge controller > > Eric T. wrote: >> Jim, >> There are different types of solar controllers. >> Some need a "bypass load" connected (like a 12 volt water heater element), >> some do not. >> >> If you buy a "smart" controller the "input resistance" varies with the >> stage of the charge cycle. During "bulk mode" the current is allowed to flow >> freely, during "absorption mode" the output voltage is controlled at the >> proper voltage for your battery type and (hopefully) the battery >> temperature, so the "input resistance" will increase steadily as the battery >> approaches full charge. When the charge controller decides to switch to >> "float mode" the "input resistance" changes to regulate the output voltage >> to the proper voltage for your battery type and (again, hopefully) >> temperature. >> >> Due to the presence of blocking diodes both scenarios are wrong. >> If one panel is putting out a lower voltage than the other (maybe partially >> shaded or pointed less directly toward the sun) the higher voltage of the >> other "parallel" panel will hold the diode in reverse bias and no current >> will flow from the panel with the lower voltage. >> Unless the panels are very nearly identical, a parallel wiring system will >> produce unsatisfactory results. >> Luckily, panels of the same size from the same manufacturer and of nearly >> the same age will work just fine in a parallel wiring setup. >> >> >> Eric Thompson >> > Hi, Eric, > > That's what I was looking for. Thanks. > > Jim > _______________________________________________ > Liveaboard mailing list > [email protected] > To adjust your membership settings over the web > http://www.liveaboardnow.org/mailman/listinfo/liveaboard > To subscribe send an email to [email protected] > > To unsubscribe send an email to [email protected] > The archives are at http://www.liveaboardnow.org/pipermail/liveaboard/ > > To search the archives > http://www.mail-archive.com/[email protected] > > The Mailman Users Guide can be found here > http://www.gnu.org/software/mailman/mailman-member/index.html _________________________________________________________________ Windows Live™: Keep your life in sync. http://windowslive.com/explore?ocid=TXT_TAGLM_WL_allup_1a_explore_042009 _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://www.liveaboardnow.org/mailman/listinfo/liveaboard To subscribe send an email to [email protected] To unsubscribe send an email to [email protected] The archives are at http://www.liveaboardnow.org/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
