Home Solar

This video explains what my solar project is:

Due to cold snap, the Permit To Operate was slipped to next week. Between the snow induced power outages and below freezing temperatures, everything got pushed off a week.

Bob Wilson

 

Some final paper work has held up the solar panels. But this is were we were Friday evening:

• 13 kWh battery - solar buffer for night.
• 16 kW natural gas fueled generator - handles any outage longer than the battery and solar panels can handle
• (16) 400 W microinverter solar panels - each panel produces split-phase, 240 VAC, pending final paper work
• 200 A, split-phase, 240 VAC, grid service - backup for low solar production and battery at 20%. Also takes any excess power produced, hopefully careful load management will make this very\, very small.
• Master Switch - mechanically disconnects house from grid.
• System Controller - coordinates all power sources feeding the house panel
• SPAN house panel (not shown) - circuit breakers for all load circuits and sheds non-critical loads to extend battery life

Snapshot during testing:


First solar panel test:


Charging the Tesla:



First EV charging result:

As I learn how to best operate, this will become more common. In this case, I had not configured the Tesla Universal Charger with the local grid cost per kWh.

Bob Wilson

 

I hired the contractor because they have experience designing and building multiple systems. They have paid the "learning curve" tuition. But looking at home-brew and my system, there are two conflicting architectures:

• individual solar panel AC inverters - each panel makes 240 VAC, split phase, and coordinate the AC frequency and phase with the other units. This means ordinary 120/240 VAC wiring and connectors for the rest of the system. Also, each panel inverter has its own solar-power controller to get the maximum output independent of the other panels that may be fully, partially, or not exposed. Regular code inspectors know how AC works as do ordinary electricians.
• large arrays of panels DC wired to single AC inverters - the 48 V panels are wired into a couple of groups with only one solar-power controller for each array. It turns out that in series, one shaded panel becomes a current limiter. In parallel, there will also be panels under producing. These DC bus systems are often wired with huge, often welder, cables, both uncommon and expensive. Then if the inverter goes down, you're toast until a replacement arrives. High power DC systems are not as common as regular house wiring AC systems.

The Saturday wind storms are here and the old tin shed is rolling itself in a ball. I heard a power pole fuse blow and the automatic 16 kW, natural gas generator is powering the house . . . the second time. There is a 30 second delay until the generator cames on. The wind is still blowing, hard.

Right in the center of the line of power outages East of Redstone Arsenal.

Bob Wilson

 

No damage visible but there will be ‘proof of operation’ when they come back for the final Permit To Operate.

Let me suggest, a couple of panels, ground mounted, with micro inverters for each panel. This will give 240 VAC, split phase or 120 VAC. Then feed a ‘luggable’ power block. Use that to handle some isolated loads like a UPS. Make sure it has grid charging.

The advantage of micro inverters is the rest of the circuit uses regulate house wiring instead of high current, DC. The micro inverters manage esch solar panel load for maximum production. Both parallel and series DC solar panels don’t optimize each panel production and one stinker screws the whole array.

Bob Wilson