diy solar

diy solar

Please review this new proposed system

DanMc77

New Member
Joined
Aug 23, 2023
Messages
12
Location
Conway, NH
Hello! This is my first post here. I promise not to just post one time and then disappear. That happens too much on forums.

Here's my story (if you don't care about all the chatter, just skip to the bottom):

About 8 years ago, we bought a 600 sq ft seasonal home on a hillside in Conway, NH. The nearest grid power is 1/2 mile away, so that won't be happening. The prior owner built the place with a generator-powered system with 4 Trojian T105 batteries. He would run a small generator for a good portion of every day to get enough charge in the batteries to make it through the night. He needed night time power because he used a CPAP machine. I operated this way for a couple months, then figured out how to run a power cable from the small 12 v battery in my Prius, directly to the 12 volt battery bank in the house (with a breaker in there in case something stupid happened). That was a huge improvement since the Prius would keep the batteries charged, and it would only consume about a gallon of fuel each day. It was like being on grid power. With all the electrical loads in the Prius turned off, but the car turned on, it would run the engine for 40 seconds per hour. It was trouble free and offered peace of mind and NO noisy generator. But...... I often needed to bring my Jeep up to haul in equipment and supplies, and then I was back to the noisy generator for that visit.

The next year, I picked up a solar system designed by a guy in Western MA. 500 PV watts, a Midnight classic 150, and a Kisae 2000 watt pure sine inverter and keeping the same charger that connects to the generator. This was my introduction to solar power. This system was a wonder to live with, but in Dec and Jan, it was not able to keep the batteries up to charge. So I added another 500 watts of PV. That helped a great deal in the winter and on cloudy days in the summer. This system has met our needs very nicely, with a passive wood stove providing heat when it's cold. For air conditioning, I've had to run a a generator. I don't have much hope of being able to power a real furnace with a small system like this. We are in a heavily wooded area with a small clearing around the house. Ground mounted solar panels is not an option.

As time past, the little one-bedroom 600 sq ft house gets really cramped when we have visitors stay for a night or two. So now we are adding another 900 sq ft with two additional bedrooms and space to spread out. And, while I'm at it, why not make a major upgrade to the power system.

The existing system is pretty much max'ed out, and maybe a bit antiquated. So I have spent some time looking at a larger power system that is expandable and in this first iteration has a good chance of not needing to be upgraded. The existing solar system will remain in place until the new system is up and running on the new roofline. Unfortunately, the roofline faces southwest, or rather mostly west. In the depth of winter sunlight, the sun sets directly in front of the panels, so winter power is severely compromised. So the west-facing system is kind of super-sized to make up for the crummy orientation. I have one small roofline that can fit two panels, so I'm putting two on there so I have at least some PV that will generate good power in the winter.

I am working with an online supplier of DIY kits, and now I think I have a final quote. If you experts here don't mind reviewing the materials list it would be much appreciated. I'd rather fix a deficiency now rather than after it's all installed. Again, this is a system that far exceeds what we need for power now, so we will grow into it over time. The two inverters gives us the ability to run split phase and get 220 volt power if needed.

Qty 2: EG4 3kW off-grid inverter, 3000EHV-48.
Qty 2: EG4-LL Lithium battery, 48 V, 100 AH.
Qty 1: EG4 3 position battery rack
Qty 14: Canadian Solar 400w Mono Panels CS6R-400MS-HL (two of these face south, the rest face west).
Qty 1: IMO DC roof disconnect switch
Qty 50: PV 2 Wire clips.
Qty 1: Tigo Cloud Connect, Tigo TAP
Qty 14: Tigo TS4-A-O Optimizers
QTY 500: Feet of Black/Red 10 AWG copper solar wire (This is a lot more than I'll need)

That's a lot for a first post. I hope somebody takes the time to read it. LOL.

Blessings to you all,
Dan
 
I guess I posted too much info. But here's my second post, as promised. I'll hang around and post again when I have something more specific to ask or report.
 
While I’m certainly not an expert in this subject and I utilize this forum to learn more myself, I’ll chime in

I would be curious about the 2 panels in different orientation and would try and keep those on a different string than the others facing a different direction.

Secondly, will you be increasing the battery size in the future? With sub-optimal array direction that was one thing that stood out to me in your list
 
Goo5e, Thanks for your feedback. On the 2 south-facing panels tied into a string with 5 panels facing west: I raised that issue with the supplier I'm using. This is why they added the optimizers. That should keep panels that are not producing from limiting the production of the rest of the string. I didn't know what optimizers did before this project.

I can always add battery capacity. The order is includes a rack that can contain 3 batteries, so I can easily add 1 battery before having to change to a larger rack.
 
Mods: Should this thread be moved to Show and Tell? There seems to be a lot of posts over there and a lot of discussion about new systems.
 
I assume there's no possibility to go with a ground-mount array?
Boy that sure would simplify things, but this place is tucked into a heavily wooded area, and it's very hilly. I'd have to remove a tremendous number of trees. As it is, I'll have to remove two fairly large oak trees just to get good solid light to the two south facing panels. I have a big row of trees a little bit down the hill on the west side, but on the roof, the panels will be able to go over those.
 
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I put in the order for this system. Now I have to get the racking ordered. IronRidge looks like a great company, but their online "Design Assistant" is a PITA. I need a sloped mount on a sloped roof for the west facing array, and it won't let me do that. If I try to do a project for a sloped mount on a flat roof, then it insists on standing seam metal roofing. I don't have standing seam. Good grief.
 
You might have missed an option along the way. I just gave it a try and was able to choose a flat roof (membrane) with a tilt kit, which is what it seems like you need.
 
If you still have the midnight charge controller, I'd wire those two separate panels into the charge controller vs splitting a string into two separate directions.
 
The generator can be made to operate very quietly, with a sound box that you can easily build around it. Youtube vids abound for such boxes. You'll want the generator (or your prius, or both) for backup purposes to solar, most likely.

Sounds like the existing inverter handles output from the existing gen just fine. The EG4's may not be as happy w/ output power from the existing gen. You can review the EG4 manual and see what they are expecting. If there is an issue with output power (perhaps too high of a THD value), you can add a "chargeverter" into the mix. Gen feeds 48v chargeverter, and chargeverter feeds the batteries directly w/ clean power (or possibly ties into the EG4's).

If ok with sharing the info, which online vendor (of kits) are you working with? Some are excellent, per forum threads, and others are possibly iffy, in terms of support. It's good that you are getting two EG4's, as there is some built in redundancy in your design, if one of these inverters takes a nose dive. I'd also search the forums for your specific inverter model, and see what others' experiences have been ...

Hope this helps ...
 
I ordered from Signature Solar. I was originally working with shopsolarkits.com, but I got tired of dealing with people in the Philipines that didn't have much depth.of knowledge. Inhad originally specified the 6000 watt EG4 split phase inverter and the first thing Sig Solar did was tell me to get two of the 3000's because they've seen reliability issues with the split phase 6000, and I also get redundancy.

Using the Midnite classic 150 for the south panels is interesting, but how does that work along with the EG4 inverters that are closely coupled with the EG4-LL lithium batteries?

I can see how specifying a membrane flat roof would get me away from the standing seam brackets. I was too honest in specifying metal.
 
Using the Midnite classic 150 for the south panels is interesting, but how does that work along with the EG4 inverters that are closely coupled with the EG4-LL lithium batteries?
Yeah, I guess I don't care about BMS comms. I'd just wire it in with voltage settings and call it done. You've already got the charge controller and you're getting extra wire. So, all it would cost you is a breaker/fuse holder or two, which you might be able to reuse from the old set up.

Seems like an easy trade of to increase the output/unload some work from the optimizers. I believe I read the Tigo optimizers can only compensate for a 25% difference in output between panels.
 
I have attached the spec for the Tigo optimizers. I don't see anything that implies a mere 25% compensation level. But I didn't even know what an optimizer was, a week ago.

Because these "batteries" are really a complex storage array of individual lithium cells, and the EG4 3000 inverter communicates with the batteries, and because I'm still coming up to speed on this system, I'm reluctant to squirt extra power in from another charge controller at this point.

I went on the IronRidge site and lied to it, claiming that it's a flat membrane roof for my racking. It let me go through the design, adding a 10 degree pitch. I'll give them a call on Monday, see what they say. I'm afraid that they'll say they only sell to licensed installers, or something like that.

I have a 1000 watt Honda generator, which is usually used for charging the existing batteries. Also a 3500 watt Predator inverter generator. Both are very quiet, and are housed in a small generator shed. When either one is running, it's just perceptible inside the house that the generator is on. It's actually nice to be able to tell if it has run out of fuel when the hum goes away.
 

Attachments

  • Tigo Optimizer TS4-A-O.pdf
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I just spent over an hour on the phone with a very nice lady at AltE Store here in MA. They happen to be in Boxborough, MA, the same town where I work. I can save shipping on the racking for my system. I can drive in there an pick up the stuff.

She really knows what she's doing. She recommended that I should use my Midnight Classic 150 to run those two separate panels, rather than mixing them into the strings on the other roofline. She also pointed out that the Tigo optimizers are intended to reduce the impact of shading, not matching two south facing panels into a string of west facing panels. My concern of interfering with the BMS interface between the batteries and the EG4 inverters is of no concern, as long as the MC150 is set up for the 48 volt batteries.
 
Here's a follow-up on my new system. It is now installed and running the house. The power is incredible as compared to the prior system. I found a local master electrician that had installed a solar system on a neighbor's house, so I hired him to do the panel install on the roof. He brought the wires down through the roof and to the system. While he worked on the roof, I hooked up the batteries & inverters and tied it into the power panel. He did the final tie in of the PV input to the inverters. The final configuration is 6 400 watt panels on each inverter, with the inverters configured in parallel. I don't have any 220 volt loads, so split-phase configuration won't do anything for me.

Wiring everything up and configuring the inverters was pretty straightforward. The EG4 printed manual was sufficient to get everything configured correctly, though it looks like some of the diagrams are for an earlier version of the inverter. Anyway, it runs like a dream.

The second string of two panels on the portico roof face due south and are thought to be the "wintertime" panels. It's a 16-pitch roof, so there will NEVER be any snow on these. The existing Midnite Classic 150 will be used for these two panels and tied into the batteries, so that still needs to be done.

Since the two south-facing panels are a separate string going to the Midnite Classic, I don't need the optimizers, so those will go back. Thanks to @400bird for that tip.


20231003_164523.jpgScreenshot_20231003_174124_Gallery.jpg
 
One more update: I finally found the time to wire in the Midnite Classic 150 for the two lonely panels on the right, thanks again to @400bird for the idea.

We don't heat this place during the winter, except when I'm there. So I'm planning to move the batteries down to the basement. The user manual for the EG4 LL batteries says that they will not accept any charge input when they are below 30 deg F.
 
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