Offgrid Solar Project Phase 3 - Complete

Phase 3 of our on-going offgrid solar project is now complete, a year after starting it. Phase 3a which was getting the new array and pole up was completed back in August. We have now wrapped up phase 3 by mounting a second pole and moving the skid-mounted array to this new pole.

This array is our original two solar panels that we have had for a couple years now and has been moved around on a ground skid from location to location. A couple winters ago we had it on the deck and unfortunately the snow on the roof unloaded onto the panels and crushed the rack and damaged one of the panels. This made us move this array to below the deck which recieved less light but was safer (or so we thought). During a wind storm, the wind picked up the array and ground skid and flipped it into the middle of the garden. Fortunately no further damage occured other than some pulled wires. From that point forward we had to hold the array and ground skid down with ropes and bricks which meant moving it to optimize the light was no longer an option. This is why this array needed to be moved to a permanent, safe location with better light.

Originally the plan for phase 3b was simply to get the second pole in the ground before the winter freeze and leave the array in it's original location for the winter. In early October we were able to get the pole cemented into the ground. As with the first pole, we used a 10 foot pole with a 4 inch diameter. The pole was mounted in a hole that was 4 feet deep, and 2 feet by 2 feet wide. The pole has two holes drilled through it supporting a 3 foot rebar cage that provide additional support as the cement sets up and prevents the pole from turning in the hole in high wind conditions. I dug this hole slightly bigger to allow for easier digging and to avoid a couple large rocks I found on one side of the hole. I ended up using 31 bags of 80 pound cement to fill in the hole for a total of 1.24 tons of cement holding the pole in the ground.

After letting the cement cure for a week, the weather held out and I decided to go ahead and move the array to its new home. I started with determining the ultimate angle of the array which ended up being almost due south. This is different then first array we put in due to the closer proximity to the forest line. After setting the angle and mounting the panel racks, I disconnected the array from its old wiring and moved the panels to the new rack. After attaching them to the new racks, I grounded them to a new grounding rod and then wired this grounding rod to the grounding rod of the other pole to make sure as much ground wire as possible was 'touching ground'.

The final piece was running the conduit and wiring from this new pole to the other pole where the circuit breakers are located. This was a total run of about 22 feet but because it was uphill, I was presented with a few challenges. I made it to the combiner box on the first pole with a total of 1 foot of wire to spare (between 4 cables). That is cutting it a little too close for my comfort, but we made it.

I tested out all four circuits and determined that I was indeed getting power from all four panels individually. It was late in the day when I was testing though and the the new array had already moved into partial shade so I will need to do further testing on sunnier days.

I completed the project by moving some of the dirt from the holes back around the base of the poles, leveling the soil and making it easier to walk around.

We are very happy with results and definately learned a lot through this phase of the project. Our total array now includes 2 205 watt panels producing a maximum of 11 amps each, and 2 125 watt panels producing a maximum of 7.5 amps each. One of the 125 watt panels is damaged and therfore the most I have ever seen it produce was 1 or 2 amps even on the sunniest of days. It is estimated that our maximum amps will be around 30 - 32 amps, but we would be happy with 20 - 25 amps.

So, what is next? Are we finally done? Well, it will take us a while to absorb the new system and see how to best use the power it is producing. We already determined that we can now cook in the crockpot on a sunny day and have all the power come from this new array. The crockpot requires about 22 amps of power which almost perfectly matches our output. We also know that we can run the home office on a sunny day without drawing down the batteries. The real test will be through the winter when our prodution goes down dramatically. We eventually need to increase the size of our battery bank up to an estimated 400 amp-hours from our existing 125 amp-hours, but that can wait until we determine how much storage we really need and how the new array is doing year-round.

Until then, stay tuned for other solar-related projects such as experiments in solar hot water and maybe even a solar-powered bike. Until then, this is Life According To Troy.