My new OFF-GRID retirement place!

Breaker boxes and battery inverter wall by Keowee Home SolarIt’s been a while since I’ve posted. I’ve still been doing DIY consulting, but all my spare time has been going in to the new house. Yup, it’s OFF-GRID, even though power is available. I’ve always wanted to do this, and this was my last chance to do so. If it flops, I can always connect to the street and have a great backup system!  Grey box is a “future use” primary input breaker box that goes through the wall to a meter, and down into conduit that goes under the driveway to the hillside. Wires are already installed, so if someone in the future wants street power, they can have the power company excavate from the hillside without tearing up the parking pad. From there, conduit feeds into the main switching area on the triple Magnum inverter (which only has 2 MSPAE4448 inverters mounted at the present time for 9KW of power), and then on to the MAIN breaker panel at the far left.

28 solar panels and 4 solar thermal panels by Keowee Home Solar

Moving to the roof, I’ve got 28 280 watt panels for 7840 watts in an ideal world. There are 14 Magnum GT500 dual micro-inverters up here that directly convert the DC voltage into 240 volts AC. There are two strings of 14 panels, and each string goes back to a 2 pole 20A breaker in the main panel. This provides both an AC back-feed into the battery inverter to charge the batteries AND at the same time provides any excess power from the sun DIRECTLY to the appliances. So on sunny days, we can do the laundry, running the washer and dryer at the same time without discharging the battery bank at all! This is dramatically different than a traditional off-grid setup with panels, charge controller, batterybank and battery inverter. The traditional setup means the power is limited by the size of the inverter. If my batteries are fully charged, I can draw 8.8KW (2 X 4.4kw) plus the 6KW from the panels for a total of almost 15KW around noon on a sunny day! I’ve trashed my big AGM batteries for the FOUR 10KW LiFePo4 batteries (orange boxes) and all connections to the Magnum interface are equal length 4/0 copper. Thus, a PERFECT matchup in terms of charging power. This also gives a daily (overnight) discharge of about 20%, which babies the battery bank and will allow for a full 6000 cycle (plus more!!) lifespan. The bank is fully charged (in normal sunlight) by 1PM each day. The panels are PERC type, and also do well on grey days, producing about 2800 watts reaching full charge before sundown even in winter. If we have too many dark days, I have a 9KW Generac that is wired to the AC input on the Magnum system. Last year it ran only once for a couple hours. No point in wasting generator fuel – just recharge batteries enough to make it through the night – sun might shine tomorrow!

Magnum router photo by Keowee Home SolarThe Magnum ME-RTR Router does a nice job of controlling all three of the MSPAE-4448 battery inverters, and allows fine tuning the BULK, ABSORB and FLOAT voltages to suit whatever battery type you have. This is CRITICAL if you want to maximize the battery life by applying the proper charge regime that the manufacturer recommends. The information display is very informative. I’ve also got a regular display that mounts upstairs where it’s more convenient to keep an eye on the system. It’s also connected to the local network for viewing on my home computer. Shows the same data, but in the form of a pretty graphic!  A Magnum MAGWEB is also connected to put the data onto my local network. IMPORTANT NOTE: if running AC coupled OFF GRID, the ONLY PARAMETER THAT WILL TERMINATE BATTERY CHARGE WHEN FULL IS THE “ABSORB” setting. None of the other ARTR settings matter!! it should be set to about 4 volts LESS than the fully charged battery will be!!! If you fail to follow this, you will overcharge your batteries! This will cause OVERHEATING of lead acid, or SHUT DOWN of ANY LiFePo4 battery with a BMS.  If your BMS disconnects UNDER LOAD, your inverters will EXPLODE!!!! Please re-read this. It is VITALLY important!

 

For those of you who noticed the 4 larger panels at the far end of the roof, those are german made 4X8 solar THERMAL panels that will heat water inside a 100 gallon storage tank. This gets circulated through a maze of 1/2 inch pex tubing embedded in 1 1/2 inches of Gypsum-concrete on the main floor providing solar radiant floor heating when needed. Each of the 4 rooms on the main floor has it’s own thermostat as well as a branch in the basement where it is converted to hot air.

DIY Solar LOW electric bill!

Almost Zero electric bill for last month!

DIY Solar results in almost ZERO electric bill for the month!

Just a quick post. I’ve mentioned my little house in the country many times and I finally found the energy hog! It was my septic aerator pump. It’s a 3/4 horse air pump, and it was running far too often. I changed the timer settings and cut my biggest energy user by 70%. I added panel #13, and I think I’ve almost reached NET ZERO energy for this little house!

Nothing makes me happier than seeing a ZERO or near ZERO electric bill. Keep in mind, the solar also covers the fixed portion of the bill that is NOT electric usage. It renews my belief that doing this is the Right thing, right now.

Solar has never been more affordable, so if you plan on staying in your home for the next 20 years, CALL ME and I’ll show you how to do DIY SOLAR in a quick, effective and above all AFFORDABLE manner! It just makes good sense.

Finish phase 2 expansion at East Fork Stables

Racking goes up at East Fork Stables

Cinci Home Solar works with EFS to get racking up using 50% on hand materials.

Missed this photo on the first part of this adventure. The owner had materials on hand, and made the posts of Steel L channel, the beams from Steel S-channel, and the barn support brackets from 2 inch steel L material. The owner (George) is a VERY resourceful fellow – some might call him a scrounger, but I call him SMART! I passed along a great vendor deal on the solar panels and he purchased them direct. The BOS (balance of system) materials was purchased through Cinci Home Solar at great pricing, bringing the whole project in at about $3/watt, and this includes the battery bank and backup power inverters in addition to the Enphase micro-inverters behind each panel. The work was spread over 4 full days, with the helper crew varying from 1 to 3 guys and myself. Plenty of manpower to get this rather large project done in a timely fashion. Winter is really variable in Cincinnati, and whenever the weather was predicted to be above 40 and sunny, George called and we got the job done. Fortunately, this job was a quick drive from my home, and it wasn’t a problem. Normally, these 3 or 4 days would have been all condensed into one extended visit! I aim to please, whenever possible…

 

DIY Solar array expansion by Cinci Home Solar

DIY Solar expansion -adding 2 more rows to bottom of 32 panel array.

After we finished the 32 panel array, George saw that some minor grading of the ground near the bottom would allow plenty of room for 2 more rows! A week later he called me and said “Hey Joe, come on out and lets get these 2 rows installed – tomorrow’s weather looks great. So we did!  When I ordered the extra components, we also added 8 more rails – one under each of the 8 columns of the upper 4 rows. You can see them mid-panel in the picture to the right. This provided the extra strength and rigidity that the span required for both wind and snow loading. Splicing the extra rails that extend to the newly installed lower beam also provided a counterbalance to the free span above.
The two missing panels at the lower left were intentionally left off because of a stone access road to the hay barn that George didn’t want to move.

 

DIY Solar install of Enphase M215 Micro-inverters

DIY Solar installation of Enphase M215 Micro-inverters.

This is what the backside looks like after everything is in place. After the rails were set, the Enphase M215 Micro-inverters were mounted. Then the #6 bare copper ground wire was run in series to each inverter. We grounded BOTH ends of the #6 copper, just because we could. Next came the Enphase TRUNK Cable, mounted with stainless steel clips to the rails. Then the panels were added, the micros were plugged in to the trunk cable and the panel leads connected to the micros. One end of the trunk cable is sealed with a weather tight cap, and the other goes to a weatherproof junction box (white) to transition to standard exterior rated 12-3 with ground romex. The romex connects to a breaker box with a 20 amp 2 pole breaker for each string of 16 and 1 string of 14 panels. Then, the entire array is nicely dressed using tie wraps so that all the wiring is suspended between the panels and the bottom of the rails to keep it from whipping in the wind or getting snagged by anything.

 

 

Power panel mounted below array

Power Panel beneath the array, mounted to the side of the hay barn.

Here’s the power panel. Public Utility Commission in Ohio says any array over 6Kw must be metered by a UTILITY GRADE meter. Got one on Ebay for $35. Breaker box on left contains the 3 solar breakers. That feeds through the meter to the master breaker box on the right. Master breaker box connects to the utility grid via a buried conduit over to the other barn that had power in it already. Below the utility grade meter is the Enphase ENVOY monitoring unit that ties all this to the internet so George can watch things from his home computer. He can share a link with his friends as well. I’ll post this link soon as I get it from George! The Utility voltage here is rather high – close to the limits for most inverters, at 254Vac. This causes a few of the inverters to occasionally shut down (to protect themselves). I’ll be looking into this further on my next visit to see how we might correct this…

 

Almost finished array by Cinci Home Solar

Almost finished DIY solar array accomplished with a little help from Cinci Home Solar!

Here’s the finished array. Still need to trim the excess rail length at the bottoms. If you look close, you might just spot some mis-alignment within the array. George got 2 pallets of panels. Same part number, same vendor, but one pallet was 1/2 inch shorter on the long side (out of spec…). We didn’t catch this till 5 were mounted in the top row. George, being a prudent and thrifty fellow, called the panel supplier and negotiated a compromise that didn’t require a return of the panels. The size only affects the esthetics slightly, and a cost reduction is pending!  The Enphase ENVOY normally communicates over the power lines, but there’s a half mile of them back to the house and that’s too far for it to work, so I added an Engenius EOC-1650 at the house as an access point, and atop the array as a client/bridge. It works great – with 100% signal integrity, and also provides WIFI to his customers and visitors! The EOC-1650 is that little white gadget at the top right of the array.