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.

A whole TOWN goes off grid in Germany!!

Found this story today, and it is really amazing how a little bit of willpower and cooperation allowed this small town in Germany to not only go OFF GRID (total disconnect!) but to also SELL power to neighboring towns at a discounted rate! Read the story here: OFF GRID GERMAN TOWN STORY

Ohio Senate Bill 58 puts solar RPS at risk

If you live in Ohio and own or are considering installing residential or light commercial PV solar, please contact Governor Kasich at his office and tell him you want him to oppose SENATE BILL 58, currently in discussion.
I’ve encouraged everyone I know to do so, and I emailed his office last week. Below is the email response I got:

Dear Joseph:

Thank you for writing with regard to Senate Bill 58. Your letter has been forwarded to me for my review. We appreciate that you took the time to share your views about this important piece of legislation.

Senate Bill 58 is currently being debated during the 130th session of the Ohio General Assembly. Please be assured Governor Kasich will keep your views in mind if Senate Bill 58 is passed by the General Assembly and forwarded to the Governor for his signature. I encourage you to share your concerns with your legislators, as your input will be important as they review this legislation.

Once again, thank you for writing to Governor Kasich. Please do not hesitate to contact the Governor’s office if we may assist you in the future.

Sincerely,

Dave Ward Director of Constituent Affairs

We must all pull together to RAISE the percentage of the RPS (Renewable Portfolio Standard) upon which the Solar SREC values are tied, if we want to preserve the extra value that this represents to the smaller producers of solar energy!! It’s currently pegged at a max of 1/2%, and should be more like 2% of the total 12% renewable energy long term goal.

Thanks!
Joe

Our power costs are CHEAP here in the MidWest!

I just read a blog at my friend’s website (www.runonsun.com) and learned that folks in California are paying 22 Cents/Kwh for their electricity. That’s over TWICE what we pay here in the MidWest. This is very likely the reason there’s so much residential solar built up out West. Our energy prices here in Ohio, Indiana, Kentucky and Pennsylvania are all around 10 cents/Kwh, and we are blessed. But don’t think that our prices won’t go up. Coal fired plants are being closed every week because they are old, obsolete, or simply can’t meet the new EPA standards for particulate emissions. Yes, there are new gas turbine power plants being built, and yes, we are using LESS electricity (as a Country) than ever before, but this is not a balanced equation. Our prices have been held low due to coal subsidies from the government, and these will disappear with the coal plants. Solar panel pricing has bottomed out and prices are stabilizing in the 79 to 90 cents/watt range. We might squeeze a few percent out of inverter costs, but for now, we are riding near the all time price lows for residential AND commercial solar PV systems. It might be time to plan on installing that dream system in the early Spring, before demand begins to force component pricing to rise…

Best wishes and sunny days!
Joe

Power Point for Mother Earth News Festival in 7 Springs PA

Just thought I’d post this for the convenience of those folks who might attend my seminars this year, and would like to review them at their leisure from home. Even if you don’t attend the fair, there’s some pretty good info in this presentation for anyone considering doing PV Solar as a DIY project. The rest of my blog is filled with lots of detailed photos and text from solar projects of all sizes and equipment types.

Cinci Home Solar presentation at 2013 Mother Earth News Fair in 7 Springs PA

Warrantee work at East Fork

Had a small problem with an SMA Sunny Island grid backup inverter (6KW). After sending SMA the Smart Card data, they promptly sent out a replacement and even included return shipping! Back up and running and customer is a happy camper once again. Based on this event, I would highly recommend you look at the SMA Sunny Island if you’re planning a Grid backup or even OFF-grid system! Sorry, I forgot my camera this trip!

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.

Serious grid-tied/grid-backup system!

DIY Solar grid backup system

Ground mounts are an attractive alternative if you don’t have much roof space and want a system that allows you to live comfortably WITHOUT the grid!!

Nestled in the middle of a 26 acre plot is this cozy updated farmhouse with almost 6KW of solar power. The home is well insulated, and fitted with all the high efficiency goodies. Propane fired DEMAND water heater, wood stove for heating, LED lighting and more! At first I assumed he wanted a ground mount to keep it away from the house, but when I arrived on site I knew right away the real reason – no room on the roof! But seriously, this setup goes way beyond just a large array. The owner wanted plenty of AUTONOMY – that’s lots of days of off grid operation without worry of running the battery bank down. And plenty of power, so that if he wants to do laundry while off grid, it won’t be a problem. So we got together and discussed the options and the owner decided to DO IT RIGHT the first time. I explained that batteries would be a large part of the project cost, and he would have to understand and CARE for the battery bank if he expected it to last 10 years or more.  He was more than willing to listen, read, study and understand the care and feeding of his battery bank, and as a result is VERY pleased with his installation.

 

DIY Solar ground mount everything in place and ready to add panels

Trench backfilled, horizontal pipe (3 inch galvenized) added front and back, and vertical rails to carry the solar panels installed. Ready for panels and wiring. Owner and a few helpers accomplished this in 2 days of hard work. Not much daylight in December, but DIY folks are not afraid to work sunup to sundown!!

While all this activity was going on outside,  I was busy in the basement, hanging the TWO Sunny Island inverters on the wall, mounting the small EMERGENCY POWER breaker box and running conduit between the inverters, the main breaker box and the new Emergency power box. I’d come up for air once in a while to check on the ground mount work, just to make sure it was square and plumb, but these guys knew what they were doing and got it all right on the very first pass!  Looking at the pics below, we chose to use TWO Sunny Islands for several reasons. 1st and most important was that the Sunny Island is without question the best BATTERY TENDER around. It can use the grid or the array charge the batteries, and it has sophisticated software to monitor the battery health and adjust things as needed to optimize the battery care. It LEARNS over the 1st 8 weeks how the battery supplies power and how it accepts charge and then adjusts itself for the best possible care. We used TWO Sunny Island inverters so that we could SLAVE them together and create 240VAC “split” phase. The Sunny Island is a 120VAC unit and would otherwise need a lossy transformer to boost the output to 240VAC.   We doubled the available continuous output power to 13,000 WATTS by doing this. That is a LOT of backup power, and will allow completely normal living in an off grid situation. The owner wanted lots of autonomy (days of power off grid) so we went with the largest batteries withing the budget – Rolls FLA 6 volt 820AH.  EIGHT of them to reach the 48VDC the Sunny Islands need.  That’s almost 40KWH of backup power. And remember, when off grid, the sun on the array will recharge them, as well as power the house!  I didn’t have time to hang around while a battery BOX was built, so we put up a poly tent and connected the vent fan. This was only a temporary fix and has since been replaced by an appropriate battery box. The exhaust fan is programmed to come on while the batteries are charging – since this is when they give off Hydrogen gasses which are explosive in small amounts.  The owner has since also installed RECOMBINATION CAPS which reduce the outgassing by 99% and reduce fluid losses considerably – making it only necessary to check acid levels in the battery every two months or so, rather than every 2 weeks. A wise investment – since it minimizes outgassing of Hydrogen if the vent fan were to ever fail! Batteries are a VERY serious bit of hardware and you MUST care for them if you expect to get 10+ years of service!  Always wear safety glasses, a rubber apron and rubber gloves when checking/filling the cells!

DIY Solar grid-tied backup system connected and ready for power!

Some of the AC lines have been moved to the emergency breaker box, all covers are on, and temporary poly cover over battery box has been connected to the power vent fan. When the battery bank charges (at 38 amps DC) the batteries bubble up hydrogen gas and without the fan and cover, the room would reach explosive hydrogen levels in less than 1 minute. NEVER power up a battery system without a vent system!! A 4% concentration level of Hydrogen gas is highly explosive.

Battery bank, inverters and emergency breaker panel on DIY Solar installation

Two Sunny Island battery/inverters on the wall, eight 6 volt 820AH batteries below elevated off floor to make watering easier. DC cables connected and AC interconnections in Plastic conduit for safety. Ready to move some wiring from the main box to the emergency breaker box. Only items in the emergency box will be powered when running off grid. System cuts over instantly when grid drops out. Barely a flicker of the lights, it happens so fast! Same thing happens when power is restored. Back on grid in an instant.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

When a lead-acid battery is discharged, the electrolyte (sulfuric acid) and the active material on the plates of the battery (lead) are consumed to produce water and lead sulfate and current flow. The chemical equation for a lead-acid battery during discharge is: PbO2 Pb 2H2SO4 –>PbSO4 2H2O Ideally it’s just hydrogen gas, but when doing Equalization charging, you’re going to get some hydrogen sulfide as well – you’ll know it by it’s Sulfur smell and the stinging sensation to your eyes! Make sure the battery box power exhaust fan works BEFORE you turn on your system. In this setup, I programmed the fan to run whenever the batteries are charging. As long as the fan is running, there is negative pressure in the box (or temporary tent in this case) so even any holes or leaks will take fresh air IN to the box/tent and then OUTside the house through the white PVC vent at the left. Happy to say that the 1st charge cycle was free from problems and there wasn’t even the tiniest hint of any gas in the room. The use of RECOMBINATION caps is HIGHLY recommended. They will eliminate almost all of the outgassing and make the battery liquid levels go down MUCH slower.

Expansion options for smaller systems

I recently got a blog post regarding expanding small systems and how it was prohibitively expensive. There was a lot of misinformation, so I thought I’d let you all know the options. If you’re putting in a “grid tied” system to supplement your power and reduce your electric bill, the minimum size system to make a difference is about 12 panels. You can put in fewer, and expand later at minimal cost if you use the Enphase M190 micro-inverters. These units DAISY CHAIN – i.e. they connect in series, one to the other until you reach a maximum of 15 per BRANCH CIRCUIT. So, you can start with say, 5 panels, and then add as many as you like, as often as you like, till you hit 15. Then, you have to run another branch circuit (Romex 3 conductor with ground) to your breaker box. I’ve actually taken this approach with my little house in the woods. Started with 5, then added 3, then 2 more, then 1 and I plan on just 1 more very soon for a total of 12 panels. The racking system can be extended by using “splice kits” and it takes about 20 minutes to add a panel, start to finish. With excellent 235 and 240 watt panels now selling for $1.09/watt plus shipping, it doesn’t really take a lot of money to add a panel and micro-inverter to an existing array. And the best part of all, you DON’T need to be a licensed electrician to plug in the 2 DC connectors from the panel, or the 240VAC connector to the last micro-inverter in your chain!

If you want your system to be BACKED UP BY BATTERIES when the grid goes down, your micro-inverter style GRID-TIED system can still be used!! Using a technique called “AC COUPLING” you can connect a Magnum MPS4024 inverter/charger and 24 volts worth of 700 AmpHour Rolls batteries and have 4KW of backup power at your disposal when the next storm takes out the power. It’s not cheap, but it CAN be done, and you have the best of both worlds, without getting stuck with a STRING/CENTRAL INVERTER that MUST have a FIXED NUMBER of solar panels for best performance, and involves handling HIGH DC VOLTAGES.

Since this original blog post, Enphase has introduced the M215 series. It is a more powerful microinverter, and it is NOT compatible with the older M190.  The M190 is still available though, to those system owners who have them and want to easily expand! My original setup with 5 panels, has expanded 3 times. 1st to 8, then 10, and finally 12 total! The old system can daisy chain up to 15 inverters on one circuit, so  still have room for 3 more! Gotta love that Enphase system. Perfect for folks on a budget!!