Friday, April 23, 2021

Day 39, 40 - Benson, AZ - TT

Thursday (39) - It's a windy morning so I'm doing the ham radio testing thing from inside the RV. By windy, there are gusts into the mid-30s (mph). This generally means that I can't have the awning out so it gets a bit warm in addition to the wind noise over the Zoom session. It turns out that there is only one candidate but 8 VEs. A bit overkill but it's still nice to be able to visit with the others.

This may be defined as the point of no return. That is a ¾" hole in the roof. I then fed the photovoltaic wires through the hole and ran them through a bulkhead fitting with two gland connectors. I filled the hole with expanding foam before glueing the bulkhead fitting down. 

Rubber inside the connectors compress around the wire when tightened. To ensure a tight fit, I filled the gland fitting with silicone caulk before tightening down on the wires. I will go over the edges and the screw heads with self-leveling Dicor after installing the panels. 

Another Apple virtual award for Earth Day. I thought the design looked kind of cool. 

Friday (40) - One of the panels arrived on Thursday afternoon. It seems huge. I screwed in the ABS mounts on the four corners of the panel and the middle of the long dimension. I applied Sikaflex 252 after scuffing the mount with 80 grit sandpaper and cleaning the roof with acetone. They seem pretty solid but in addition, I used a stud sensor to locate the aluminum roof “beams”. I put one screw through each bracket into a beam to hold while the glue dries. 

Here is panel one of three. After the Sikaflex cures for a few days, I’ll cover the screws with Dicor. I went ahead and terminated the photovoltaic cable with MC4 connectors and added the 15amp fuse to the positive side. I then verified polarity at the switch before feeding the charge controller. 

This is the screen on the Victron phone app showing panel and battery voltage and current. With only one panel, the resistive loss in the 82’ of cable from the roof to the charge controller is significant. With two more panels in series, the resistive loss will be less significant. 

No comments: