Catching Up: Mid-December

First, let me apologize for not updating my blog for several months. Life is busy and while the path may have been a bit rocky, the ultimate outcome of this project has been very satisfying.

When we last left the story, the day was too long in the tooth to do any MMU/LMU testing. The next morning, after sunrise, I was back outside with my handy Fluke 12 Multimeter checking the string voltages. All three strings were reporting full voltage of around 385 VDC! I decided to keep an eye on things and move ahead with getting the Tigo MMU up and running. Doing so would allow me to monitor each individual panel performance on the Tigo web site.

The MMU connects to the Internet in order to send data to Tigo's data center. There is a 'gateway' box connected to the MMU. This gateway communicates with the LMUs wirelessly. It allows the MMU to collect performance data and to control the power output of each module.

The Tigo gateway is connected directly to the MMU by a small, four conductor cable. The cable is quite long and allows great flexibility in the placement of the gateway, which I was to learn later was very important.

Here's how it all fits together, communication-wise:

I temporarily installed the MMU in our laundry room, which is just through the wall from our main electrical service panel and with a convenient ethernet nearby. I placed the gateway in the window with the face of the gateway aiming towards the array, connected the ethernet cable, and plugged in the power.

Things are looking good: The MMU 'boots' up. I play with the simple menu system and discover the IP address and see that it's connected to the Internet. Then it's a quick trip to the Tigo web page showing my system and...

...everything is gray. No information coming from the LMUs! Hmmm.

In the meantime, the electricians have a job to do in Deer Valley and I must wait a couple of days before they can come and get the inverter mounted, the high-voltage DC wiring run to the inverter, the AC feed to the main service panel, the outside AC disconnect installed, and various other odds and ends.