I use a tristar TM45 MPPT controller with two 12 volt solar panels in series. I went with MPPT not because of efficiency but because I can still charge when it is cloudy or there is shade on my panels. I have my panels mounted on the top of my van and it keeps my 140 amp hours of batteries charged year round while I use my radio and my 12 volt refrigerator.
I have seen some misconceptions about MPPT. The best reason to use MPPT is so that you can put multiple solar panels in series and you will not exceed the maximum input voltage of the controller. The controller will continue to charge even in partial sunlight just as long as the input voltage exceeds the battery charge voltage (in this case 14.xx volts). Since solar panels in series ADD voltage, with two solar panels you get a 24 volts (well, more like 32 volts in full sunlight) and when those panels are in shade, the individual panels may drop down below 12 volts but the sum of the two will be much higher than the required charging voltage. My off grid system in on/in my van runs 24/365 even in the great North West where it is gray for 6 months out of the year! GL 73, Paula NX1P -- View this message in context: http://elecraft.365791.n2.nabble.com/Who-sells-a-small-RF-quiet-solar-charge-controller-tp7628064p7628295.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
