Wednesday, May 3, 2023

New Solar Panels on the New Roof

The reason we got a new roof was because we needed a new solar system.  Our 17-year-old solar system has been flaking out for months.  At random times, it would trip the circuit breaker for the PV system, and shut itself off.  I could not get anyone to come and fix the problem.  The company that installed it is long gone.  The equipment that was used 17 years ago is no longer what is used.  So it seemed the simplest fix would be to just remove the old system and put on a new one.

And that required a new roof.  Putting on a PV solar system is a major deal, and it goes on the roof.  You don't want to have to take it off, put on a new room, and then put it back up, if you can avoid it.  So if you want a PV solar system, it makes sense to make sure that the roof will be around a long time. 

To put on the new roof, we first took off the old solar system.  Then we got a new roof.  Then we installed the new PV solar system.

Originally we thought it might work best to have one company do both the roof and the solar system, but we could not make that happen.  Roofing companies want to do roofs, and solar companies want to install solar systems.  So we went with one company for the roof and another for the solar system.  We tried 4 different companies with bids from $15,159 to $23,098.  All the bids were for slightly different systems.

The main difference was in the panels.  Our original panels were about 26x56 inches, 30 pounds, for each of the 24 panels, generating 130 Watts.  The new panels are all 410 Watts, 41x74 inches, 50 pounds.  So 14 panels will generate about twice as much power in 20% more space.

Those numbers are for the QCell Q.PEAK-DUO-ML-G10+ 400 panels that we got.  The other bids were for panels from Axitech, Peimar, REC and other manufacturers running from 330W per panel to 410W per panel. 

We decided to go with Longhorn Solar.  They were not the least (or most) expensive, but the panels were very efficient and the contract easy to read and understand.  The contract specified the panels, the inverters and optimizers, monitoring system and racks, a complete "turn-key" system.  It also specified that it could take up to 150 days (5 months) to complete, because it all has to be approved by the City of Austin, and that can take result in long and ill-defined delays.

We signed the contract on 6 March.  The old solar system was removed on 8 March. The roof was replaced on 15 April. And the new solar system was installed on 1 May.

They showed up early, at 7:40AM, and started right in on the electrical part of the system.

They removed the old cut-off switch and PV meter box and put on new ones. Then installed the new inverter (a Solar Edge SE5000H model) and monitoring box.

They ran the conduit for the power from the roof up and thru the roof eave, rather than going around it.

In the meantime, another truck had arrived with the solar panels and such.

 and they went right to work putting up the rails that would hold the solar panels.

and the conduit for the electrical wiring.

Then they started putting the panels in place and wiring them together.

Two rows of 7 panels each.

By 3:45, the panels were all in place and we were generating solar power once again!

In the two days since it was put up, we have generated 50 kw.  Of course not all days will be as bright and sunny as these past two.