Hi Gordon,

Are you power limiting near noon on clear days too?

Ron

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by Ron Schroeder:
Hi,

Now that several of you have been running FishBowl on the upgraded inverters with large arrays for a while, is there any better idea on what the largest array size to use on a Sun Tie GP 2500 without maxing out the inverter on cloud enhancement too much?

Thanks,

Ron<HR></BLOCKQUOTE>

FWIW, the one inverter I have that has 3400 watts of panels (40 BP-585s) also sees limited power output around solar noon on clear days.

arnold

Hi Arnold and gorden,

It looks like 3300-3400 is a little more than necessary for the upgraded inverter. Unfortunatly, I don't have enough space that isn't shaded by the neighbors trees to have that problem. [img]images/smiles/icon_rolleyes.gif[/img]

I am meeting with several people here at work at lunch today that probably will be adding solar to their houses. They are most likely going to use the Sun Tie. One of them has 2 roof sections that might each hold about 3kW or possably more. I am thinking of reccomending 2880W each.

Ron

Ron,

I'm power limiting with my 3600 watt array under clear sky conditions when the weather is cool or the wind is blowing, i.e. my MPPT is up at say, 62 volts or more around noon, otherwise max. output ranges from say, 2425 to less than 2500 watts. The truth is that I am not altogether happy with the current produced by my array. See earlier post, it is basically this, the array's rated MPPT current is 53 amperes, I have never seen greater than 46.5 amperes under non-limiting, clear sky conditions. Henry doesn't think my array is under performing, but I do. Among my concerns is Siemen's method of spec. power on the SP75 -- actually rated at 70 watts or more, with no info on typical rating. At times I think I've a bunch of defacto SP70s with 2 years of exposure to the sun. I think that this array should produce better than 50 ampers at times in clear sky conditions.
Gordon

My 2880 array (24 KC-120s) has power limited at 2508 watts. Happened last month with cloud effects on a rather cool day. Today's max was 1668 watts (I don't know what the panel temperature was, but it's 80 degrees in my living room at midnight).

So my guess is that 2880 is about right. It will rarely limit during cloud effects, and generally run in the 1600 to 2000 max watt range. Maybe it all depends upon your local temperatures. If you're running an air conditioner in a smog pit on a 100 degree day with time of use metering, then maybe you really need those hot afternoon watts.

Just to add another wrinkle, TOU metering that runs noon to 6 would seem to favor southwest facing panels. No use collecting cheap photons in the morning when there are more lucrative ones in the afternoon...

[ May 29, 2003: Message edited by: Rob Larson ]

Is the limiting very solid, like +/- 1 watt?

BTW, here on Long Island NY, we can have time-of-use metering but the solar must be on a second non time-of-use meter.

Ron

[ June 19, 2003: Message edited by: Ron Schroeder ]