Monday, September 28, 2020

Sixth Emporia

 I just added my 6th Emporia energy/power monitoring system.

https://emporiaenergy.com/how-the-vue-energy-monitor-works/

My first five are "gen1"; "gen2" recently became available.   I just installed an 8 CT gen2. Initially, I've using 7 CTs.

I recommend as being very cheap as well as cost effective.  The "gen2" is offered with either 8 or 16 CTs.  The main box of each offers 16 CT connections.  So, you could buy one 8 CT version and one 16.  Then use more than 8 CTs on each.  Say 12 on each or 10 on one and 14 on the other.  This install was only about 1/2 day from start to working; that includes a lot of time searching for breakers and such.  The gen2 8CT is $110, gen2 16CT is $150.  I see they have some gen1 8CTs that are $85; they were priced at $100 so they are likely closing out.

https://shop.emporiaenergy.com/collections/emporia-products/products/gen-2-emporia-vue-whole-home-energy-monitor

CT == "current transformer".   Space permitting, a CT easily clamps around a AC wire and is plugged into the Emporia main box. One CT allows monitoring of current/power/energy on one wire.  The main box has both wifi and Bluetooth wireless connectivity.  The box is initially configured through Bluetooth with an app on a smart phone.  After configuration, the box continuously updates a cloud based data base through the wifi internet connection.  That data base can then be accessed from anywhere through the smart phone app.  Browser based access is planned but not currently available.

I recently received three new gen2 units and just installed one on the old meter / main breaker box at the old barn.  AKA "pool" or "PV shed".



For zoomable images:

https://photos.app.goo.gl/3PoQJRVSbKzudEyX8

This is a 15 kw transformer so production is limited to about that.  There are about 6 arrays of panels totaling about 100 that are now monitored.   The monitoring will allow me to better guess how much more can be added.  I THINK I'm near the limit so changes/additions will likely be converting to E/W rails.

 For trusted people who pledge not to mess with the configuration, I will supply my Emporia log on credentials.

Tuesday, September 15, 2020

Sept 2020 construction projects

The one hour work days seem to be over!

 https://photos.app.goo.gl/YhmKvFxxbMHaTkoi8

I'll be adding to that album as projects progress.

Instead of replacing, I decided to fix my 10' shredder so it has a fixed height rather than being hydraulically adjustable.  The lift mechanism involved wire cables that needed to be replaced. A successful fix!  I need to catch up on my shredding.



I have two newly constructed rails, one across the road and one near the house.  Each three joints of pipe, near 100' long.  I expect each rail to support 28E+28W panels and feed a 6kw transformerless Delta inverter.  The Deltas have failed to work on the panels I've been using with transformer inverters and these two new rails will be using panels that are touted to have no such trouble.



A new building, roof only, is going up over the guest house slab.  About 40'x70'.  There will be ~20' north of the slab which might be used for protected RV parking.



9/16/2020

Things go fast when rails are in place and other material is ready to use.  Over the time of two days, I have the two new rails partially populated and producing.  11 panel pairs on one rail and 9 on the other.  The really good news is that the different panels seem to be allowing the transformerless 6kw Delta inverters to work.  The Deltas are both cost effective and well suited to my needs.  I think each will support 26-27 panel pairs.   I have a little exposure to high wind since none of the new panels are well secured.  I have the choice of "doing it right" and  producing more power.  The choice I've made is obvious.  But, I hope to get everything secured in a few days.  I have the 20 pair producing and should have room for a total of at least 54 new pair.

In the afternoon:  I think I have 12 pair plus 11 pair installed and producing.  Started the securing task.  Two weeks ago, I would not have considered afternoon work.  So far, EVERY CanadianSolar panel in new shipment has had to have connector replacement.

9/16/2020

Shed project was completed yesterday.  I've NEVER put up a building which seemed "big enough" in the years following erection.  I may put a high deck in the "away from the brush" (west) section.  Something to shoot hogs from.  I see I can put a trailer under the west end as well as the north.  The height allows rain to blow all the way through; may have to do something about that.

The new Delta rail across the road is REALLY sweet.  A bit less than half the rail is producing near 3kw at times.  That's two combined strings of about 14 on one of the two trackers.  The new Delta rail near the house, not so much.  A shower induced an "isolation fault".  It took a day for it to straighten itself out, but is working now.  Will continue to populate it.

Strings are REALLY troublesome.  I found one bad new panel as I was adding to new rail.  It seems a good strategy is to measure short circuit current with a clamp on amp meter.  Comments solicited.   On strings, one bad panel screws the whole string and the bad one is difficult to find.   My two faced rails make checking panels difficult for both micro and string inverters.

9/19/2020

I'm out of panels for the Deltas.  I believe I have 14+9 pair of panels on one rail and 13+10 on the other.  Of the 8 strings, I have 2 not producing.  Still working on finding the problems.  I have at least two other string problems on older installations.

SO! All new projects near to stopping points.

9/20/2020

Two rats killed.  Three more strings working.  Still have a problem near the pool but that is $.03 electricity.  Total of 46 pair of panels producing on the two new rails.  Room for, I believe, 56 pair.  Production is near 4kw per rail for much of the day.  Might go over 5kw when/if all slots are populated.

Especially across the road, I'm hoping for a new production record of over 300 kwh.  With not perfect days, I've been doing ~280 kwh/day over there.

9/22/2020

Sadly/alarmingly/disappointingly, all transformerless inverters have been down for more than a day due to wet conditions.  The new Signature panels worked several days in dry conditions; that was a notable improvement over the Santan panels.  Not good enough, though.

Regrouping.  The only transformer string inverters that seem to be available in quantity are the SMA/SunnyBox 4kw.  So, I'm considering putting two on each rail even though I think 4kw capacity is more than can be used.  I plan to test a SMA 4kw with two strings: 14-15 E and 14-15W and see how much power might be output.  I'm not sure 15 panels will fit on half a rail but know that 14 will.  I have a few PVPowered transformer inverters that might be used but the specs indicate a voltage limit of about 13 panels.  The SMAs are spec'd for higher voltages.  I can consider dividing the rails into 15 and 13 panel strings; though that might lead to costly mistakes.


Saturday, September 12, 2020

Old friend recalls 1973 motorcycle trip to Mexico City

 I sometimes reminisce about that trip we took to Mexico, me on the SuperHawk, you on the 2-stroke Kawasaki 750. There were some interesting episodes. 


We left Austin in October, on the coldest day of the year until then. Heading south to connect with the old Panamerican Highway, it started to rain at Reynosa. The further south we went, the harder it rained, but it warmed up a little. We spent the night at Tamazunchale, in a cheap hotel across the street from the bus station. At dinner the truck drivers at the next table began to regale us with baroque tales of spectacular road accidents. The next morning it was so foggy you could see the backs of the buses parked across the street, but not the fronts. Undeterred, we started up the mountain.

After a few times coming around the corner to find big rocks in the road, or big rocks falling from the cliffs through the clouds and fog onto the road, we figured out why there was no traffic. The truck and bus drivers knew more than we did. Coming to the first short straight and level stretch in many miles, I decided to dry off my front brake. I squeezed the brake handle, but nothing happened. i squeezed a little harder and the rusty spot in the cable came loose, the front wheel stopped turning and I went down. I had on a rain suit, leather jacket, good gloves and helmet. As I slid along on my back, I noticed the bike headed for the guard rail, and thought, "If it goes under the guard rail, there's about a 1500-foot drop." Then I thought, "If I go under the guard rail..." Both the bike and I stopped before we went over the side.

Neither I nor the bike was notably damaged. We rode on until we came to the big Pemex station at Ixmiquilpan, the top of the long climb up the eastern slope of the Sierra Madre. The gas station has a good sized restaurant which has a beautiful view on a clear day. That day the visibility was about 20 yards. We were the only customers in the big restaurant. We were soaking wet. I was covered in mud from my sliding excursion. You literally poured water out the the sleeve of your rain suit onto the floor. By and by a pretty young girl, maybe 15 or 16 came out to wait on us. She looked at us, held in the giggles as long as she could, but broke down and fled back to the kitchen. After a while we could see her and a woman looking through the window in the kitchen door. The girl came back out, collapsed in giggles again, fled, recovered, and finally kept it together long enough to take our orders.

Coming in to the outskirts of Mexico City traffic began to thicken. I was out in front, stopped at a red light, when I heard a couple of loud thumps. Turning back to see what was going on, I saw you methodically kicking the driver's door of a taxi that had been crowding you. The driver sat still and looked straight ahead, studiously avoiding eye contact.

In Mexico City we checked into the Hotel Yale, near the big train station. The neighborhood was pretty dicey, but the Yale was clean, cheap, safe, and had a walled parking area for the bikes.

Riding in the rain for a few days rusted the key into the SuperHawk's ignition lock, where it couldn't be removed. I figured it was okay, since the bikes were in the walled and locked enclosure. The next morning we found that kids playing in the parking enclosure had turned on the headlight and run down the battery. We walked a couple of miles to the only motorcycle shop I knew of in Mexico City to buy a new battery. There was a big burly Mexican there, with an impressive beard, working on a cool looking old motorcycle. A sign above his head read, in English and Spanish, "This is a 1937 Zundapp. It is not for sale, and I will not answer any questions."

You stood looking over his shoulder for a while, then said, "Making a wet clutch? I made one once..."

Soon you and the big Mexican were friends.

Heading back to Texas we stopped for the night in Matehuala, a dusty former mining town. Driving around looking for a cheap hotel I remembered, we passed some teenage boys standing beside a pile of dirt that had been dug out of a deep ditch along the side of the street. Wandering around looking for the hotel, we ended up driving by the boys again. They threw a few clods at us. After turning the next corner I didn't see you in the rear view mirror. Retracing our route, i came upon you standing beside the ditch. "Where are the boys?" I asked. "Down there," you replied, kicking a little dirt into the ditch.

We ate a bunch of flour tortillas and drank some beer at the bus station cafe, then walked around and came upon a nice big brightly lit bar. We went in and sat on bar stools. The back bar contained a line of bottles of different brands of tequila that was several feet wide. When we ordered shots, the bartender asked which brand. You indicated the leftmost. After finishing our shots, you indicated the bottle next in line and asked, "Have you ever had that brand?" "No." You ordered a couple of shots from that one. Then the next bottle was sampled, and so on, until I lost track.

How we made it back to the hotel is still a mystery to me.

Next day we made it through Monterrey, and onto the new highway north toward the border. When we came to one of the big cuts through a mountain for the new road, you said, "Let's take the old road."

It was narrow and twisty, and came out on a high cliff with a nice view of the setting sun. We got out the tamales we had bought in Monterrey and had dinner. Then you said, "We might as well smoke the rest of this dope before we hit the border." I am confident the statute of limitations has run on that criminal activity.

We started back down the mountain to the highway, turned a corner and found ourselves in the middle of a herd of cows crossing the road. You were in the lead. One panicked  cow just about charged into you, but you whacked her so hard on the nose she nearly went down on her knees. She stopped and turned away. Some benign influence similar to the one that got us back to the hotel the night before, led us safely through the herd of cattle.

We stopped for the night at Sabinas Hidalgo and checked into the hotel above the bus station, still feeling a little elevated. The desk clerk eyed us suspiciously, but took us down the hallway to the room. There were two beds. I tossed my helmet onto the one next to the window, to claim it. Laughing merrily, you picked me up and bounced me off the wall onto the other bed. The desk clerk was last seen retreating rapidly down the hallway.

After we made it through the border and the checkpoint a little ways north of Laredo, you fell in behind a big new Chevrolet full of people from Mexico, and disappeared over the horizon at about 95 mile per hour.

Linda, the kids and I used to head to Mexico between Christmas and New Years. A few months after the motorcycle trip we stopped at the Ixmiquilpan Pemex station in our big red Pontiac. It was a beautiful day. We were looking forward to a good lunch and a nice view. We went in and took seats. The same young girl came out. She looked at Linda, checked out the kids, and turned her glance to me. She recognized me as the mud covered motorcyclist, broke into giggles and fled to the kitchen. Linda turned to me and said, "I'm sure this is going to be an interesting story."

....at least that's the way I remember it.

Saturday, September 5, 2020

Large test of one East plus one West facing panel on a single micro inverter

                                                     Rail1 on left, then Rail2 and Rail3


       Two panels hooked to one Enphase M215 via splitters; the west panel is propped up to allow photo.

        Small black plastic breaker box that has one breaker for each rail

        White stuff around breaker box is Emporia monitoring system.  That is supplying the data below.

         White 14ga romex will feed AC to the far end of string of drop cable.  

                                                  19 drops is a little beyond the limit of supplying AC from one end only.



                                       All three rails with the building that supplies some morning shade to Rail1


 I intend to post some daily energy harvesting data here on three rails, each with 19E panels and 19W panels.  Rail2 and Rail3 each have 38 microinverters, one for each panel.  Rail1 has been converted so 19 microinverters each serve two panels.  Rail1 gets some morning shade from a nearby building and some evening shade from Rail2.  Rail2 gets some morning shade from Rail1 and evening shade from Rail3.  Rail3 gets only morning shade from Rail2 and none from the west. 

Cost of the 1 panel 1 inverter units is about $110/panel.  Cost of the 2 panel 1 inverter unit is about  $79/panel.   After the conclusion of this test I expect to start converting Rail2 and Rail3 to 19 inverters each.  These conversions free up inverters and cabling for new installations.

Saturday Sept 5 was a mostly cloudy day with overall energy production about 60% of a good sunny day. 

Rail1        21.88 kwh 

Rail2        19.93 kwh

Rail3        24.32 kwh

Sunday Sept 6.  More sun than yesterday.  "Partly cloudy".  Maybe 80% of a good sunny day

Rail1        24.0 kwh

Rail2        22.66 kwh

Rail3        27.37 kwh

Monday Sept 7.  Pretty good sun! Maybe 90-95% of an all sun day.

Rail1        30.37 kwh

Rail2        29.27 kwh

Rail3        34.52 kwh

Tuesday Sept 8.   Fully overcast all day.  About 50% of a good day.

Rail1        19 .92 kwh

Rail2        16.71 kwh

Rail3        22.03 kwh

I'll likely call an end to the test after Tuesday's data.  Tuesday looks like cloudy all day.  The results are clear: The energy lost to a pair of E/W panels sharing an inverter is not significant; especially when ~40% hardware savings are considered.   One second power sampling does reveal that energy is lost when both panels get good sun.  For that reason, I believe the scheme will work best when panel slopes are steep.

Well.... one more day  Wednesday Sept 9 was cloudy and rainy all day. Maybe 30% of good day.

Rail1    11.18

Rail2    8.45

Rail3    12.55

I don't believe shading is the cause of low production on Rail2; I suspect one or more non functioning panels though I have no easy way to confirm.  The production on the converted Rail1 is about 10% lower than that of Rail3; that meets my expectations.

Here is a post after the 3rd rail was put in production about a year ago:

https://wmckemie.blogspot.com/2019/09/3rd-twofaced-rail.html

And another post dealing with the beginning of the 3 rail project:

https://wmckemie.blogspot.com/2019/07/first-new-project-on-across-road-meter.html

I put in the first rail, the one recently converted, not fully intending to add rails 2 and 3.