Guppy,

If the Xantrex tool had the Photowatt panel configured for 12 VDC I would give it a try. I only see them set for 24 VDC.

Even at open circuit voltage max is 520 volts with all 26 panels.

Any ideas how to get the tool to be happy with the 12 VDC configuration.

Regards,

PFM

Just select one of the 12V panels, the voltage is identical ( even different manufactures ) all Si is the same on the power totals would be different

And no, your using the "standard" 77F/25C value, thats the issue, with 26 panels you would be over 600V for sure at lower tempatures

Guppy,

Well I am in the joys of replacing the ST with the GT, first thing I had to re-locate my main roof conduit, the GT is a bit wider than the old ST. That aside I have decided to go with two strings of 13 panels all configured for 24 VDC. I expect no troubles. With a long night I hope to complete the wiring changes to the panels and have a working PV system tomorrow. Thanks again for your help.

Dave

Well all up and running, two 13.2K plus days already, best on STX is 12.6K.

Thanks all,

Dave

Hi there,

Early this year, I also changed out our Xantrex STXR for a GT2.5. And yep, I also had to rewire all my Photowatt PW-1000 panels. It was a chance to recast the entire system.

Meant several weekends up on the roof, and running a few lengths of conduit through the attic. But surprisingly little cursing. The GT-2.5 is a very nice unit, and its design is well thought out.

I also noticed an increase in output -- perhaps 10 percent or so.

Cheers to all,
-Cliff