On Grid, Off Grid Project Results

Solar PowerHouse. the modules in the background are gridtied and some can be switched to DC

Battery wiring is a temporary set up to be upgraded

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Back on June 20th, I posted about a fairly simple yet sophisticated solar battery system. I finally got the last of the wiring done last week. In the top picture is the "PowerHouse" which I designed and had local Mennonites make as a prototype two years ago. The idea was to build finished solar systems either gridtied or offgrid battery. The slope of the roof is 38 degrees which is the latitude of southern West Virginia. It fits 6) 230 watt modules, although today you can get 250 watters at less price.
The next picture is inside the PowerHouse showing the batteries, charge controller, combiner and inverter. For a full description and a link for the schematic drawing go to my June 20th post "Sensible Solar Battery System".

Two of the three series relays. Note Enphase microinverter behind timber

On July 5th I posted a schematic of a method of switching gridtied modules to DC so additional power can be collected for the battery system. I was a bit concerned the points in the relays might get damaged by under-load switching. I saw no visible arcing switching back and forth, so I suppose it will work for a long time.
The relay and it's socket are under the middle of the PV module and well protected, None the less, I used silicon dielectric grease on the wires, blade slots, and around the base edge of the relay since it didn't look like it was hermetically sealed. Then on top of that, I sprayed an anti-corrosive into the wire sockets and clamp screws. Ought to last for a while. Please note: I used "touch safe" sockets for added safety.
Basically, I doubled my collection power from 1380 watts to 2760 watts. Theoretically, I could charge the battery pack in 4 sunny hours. So yea, now I'm thinking of another set of 4) 220 A/hr batteries for winter conditions. Cha Ching..but that's the nature of the beast and human nature.

Close up of DPDT relay, socket and wiring

Different way to have battery backup on gridtie

This idea came directly from my previous post on a practical PV backup system. I have some grid tied modules nearby my battery backup shed and wanted to employ the grid tied modules to help out when the power was down. I decided to switch 6 modules into a 2 x 3 panel series string to feed the charge controller. The above diagram represents one string. It will deliver >100 VDC @ ~8A. My charge controller, an Outback FM80, can take in up to 150 VDC.
By using 120 VAC for the relay coils, it will automatically switch to DC mode if the grid goes down or you turn off the supply switch. Care should be taken switching in full sun/load conditions. It could shorten the life of the contacts in the relays. Disconnect the AC and DC sides of the system when practical.  You could install 4 RC snubbers on each relay or buy solid state relays. Either is kinda expensive. There may be no problem at all.
I'll be installing this over the next few days and I'll let you know how it works, or not...