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Addition to present array http://solar-guppy.com/forum/viewtopic.php?f=4&t=702 |
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Author: | Doakes [ Sun Oct 12, 2008 3:10 pm GMT EthGMT ] |
Post subject: | Addition to present array |
I am considering an addition to my present system. Now I have 1800 watts and Sunny Boy inverter. Grid tie. Working good and on a tracker. I wish to increase my array. Thinking about Evergreen panels, removing my present panels from the tracker and put Evergreens on the tracker, say about 2880 watts. 16-180 watts. I wish to put the present 1800 watts on a fixed pole or ground and then the 2880 on the tracker, and preplace the Sonny Boy with a larger inverter. My question, is this the best idea? or should I simply add another inverter of sufficient size(2880) and run two inverters to the grid? I wouls appreciate your differing ideas. Thanks, Dave O |
Author: | BB [ Sun Oct 12, 2008 3:58 pm GMT EthGMT ] |
Post subject: | Re: Addition to present array |
Dave, It is probably a wash technically... You can put panels sets (say 10x32 volt panels) on an east roof, and another 10x32 on a west roof, and then parallel the two strings together into one inverter and as long as all of the inverter ratings are met--will work very nicely and only a point or two off of optimum efficiency. Just to be clear--you want the entire string of 10 panels that share a roof direction to be connected in series together... You do not want to have 5 panels from the west in series with 5 panels on the east roof in one series string--that will dramatically reduce power output (basically, the panel Vmp voltage is similar on east/west roof lines (once the panels have sun)--but the current is directly proportional to amount of sun light..). So the reduced sunlight on one plane will reduce the overall current of the whole string. From what I have seen, 3kW GT inverters (and above) seem to be pretty competitively priced (close to $0.50 per watt or a bit more, the smaller inverters can be $1.00 per watt). So, I would go back and ask some other questions... Like, do you want to monitor the inverter's power output? Getting a new, larger unit, or a compatible smaller unit with the first inverter--which give you the monitoring functions you want. (Xantrex, GT family, for example, can daisy chain multiple inverters together and all be read with one computer interface--IIRC). The other option would be--are you interested in off-grid for backups/emergencies? Perhaps you can backup or redo your system with an Xantrex XW GT/Off-Grid compatible system... (Personally, I use a small Honda eu2000i generator for my emergency backup--power is very stable where I live and the batteries are, currently, just not worth the investment for a once in 50 year five-day-grid-failure). In the end, probably just run the costs out for the several options and see which gives you the best bang for the buck and meets your requirements. -Bill |
Author: | Doakes [ Tue Oct 14, 2008 7:42 am GMT EthGMT ] |
Post subject: | Re: Addition to present array |
Thanks Bill, You give me good food for thought. Dave |
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