Mountain cabin off-grid

Horsefly · November 2016

mcgivor said:

Just on the sideline reading, one question for Horesfly, is your well a deep or shallow as the pump demand is pretty high. What I've done is use a deep well pump powered by a generator to 3000 liter(800 gallons) holding tank then use a smaller demand pump to provide running water. The smaller pump can be used in shallow wells up to 8 meters (around 26 feet) suction head. Have a float switch which cuts the feed to the demand pump when the tank is low, work like a charm and the demand pump is only 100W with a small holding reservoir to maintain pressure. Have to pump about once per week with the generator, two people using, there are larger models available, not sure if these are available in the U.S but there must be something similar. See picture attached.

@mcgivor - I think our situation is not nearly as bad. Our well was only drilled to 90 ft, and the pump is down a little over 40. That is, we have really shallow ground water. The pump is on 1/2 hp, so should draw about 12A @115VAC when running. I'm a little concerned about the in-rush current, but I'm hopeful that it won't exceed the 5 sec spec of the SW4024 of 7000W.

Having said that, the pump itself is now 42 years old (wow!). Even though it is still working fine, I can't help but think it is going to fail sometime soon. When it does, we've been thinking of something a little similar to what you are suggesting. We may want to go with a bigger tank (right now we have a 75gal pressure tank), and a low-flow, low-power pump. I've looked into some (including some DC pumps) that can probably work.

Horsefly · November 2016

softdown said:

Shutting down the inverter that early would mean about a 12.2/24.4 shutoff point. There exists no really great reason to do that with deep cycle batteries. I would urge an 11.5/23 volt shutoff. Many here claim that is still too high. Inverters will let you run below the shutoff point for a specific time. Usually enough time to run a microwave or power tool. Certainly enough time to meet the surge needs of high amp motors.

I might consider buying a spare panel in case one goes down. Panels work best when they are perfectly matched. But then, I may get carried away with the old "Be Prepared" idea.

I'd like to see this cabin paradise someday. If you folks require a strong back just let me know. I could bring a backhoe but bad experiences with Colorado passes. Cheaper to rent...

Thanks @softdown.

I'm guessing we'll just need to experiment with it. Except when the pump is running, there will likely be a pretty small draw on the batteries. I think I read that the default shutdown on the SW4024 is 10.5V//21V, which is clearly too low. You may be right that more like 23V may be Ok.

Since we are just buying the panels now, I'm hoping that if we need to get a replacement they will still be available for some time.

We do already have a backhoe, but we may need an extra strong back. For now, my brother-in-law and I, and perhaps my brother (if he isn't overseas) should be enough.

Steve

BB. · November 2016

Here is the Midnite link in Westbranch's post (I will fix in earlier post too):

http://www.midnitesolar.com/pdfs/MNSW4024-KID-B-REVI.pdf

-Bill

Dave Angelini · November 2016

The GFI is built -into the Schneider 60 amp and 80 amp controllers. I know the store here is very good with helping you find a solar panel that they sold you if they become unavailable during the early part of the warranty. My supplier does this with all of the equipment they sell me and any good dealer should take care of their customers.

westbranch · November 2016

Hfly,
I'll take a look at the breaker sizes. Like I said, I wasn't even going to put a combo box in, but was persuaded that it would be useful to disconnect one string at a time. Hence my thinking that the breaker isn't really to be a breaker.

my comment is trying to address the issue that the CBs are too big for the location if you add more panels in the future... at 3 strings of panels you need them to be the right size to provide protection ...in the mean time they are good for use as switches.

Horsefly · November 2016

Dave Angelini said:

The GFI is built -into the Schneider 60 amp and 80 amp controllers. I know the store here is very good with helping you find a solar panel that they sold you if they become unavailable during the early part of the warranty. My supplier does this with all of the equipment they sell me and any good dealer should take care of their customers.

Thanks Dave. At least that explains why MidNite Solar puts a GFI breaker in some diagrams and not in others. I thought I had read the install manual on the Schneider MPPT60-150 and don't recall seeing anything about it. I am still a little bit baffled by the concept though. In an ungrounded DC system like the battery bank and CC, what is the GFI protecting?

Steve

Horsefly · November 2016

westbranch said:

my comment is trying to address the issue that the CBs are too big for the location if you add more panels in the future... at 3 strings of panels you need them to be the right size to provide protection ...in the mean time they are good for use as switches.

Thanks @westbranch. I also admit that I should have sized either the two breakers in the combo box or the PV cutoff breaker in the E-Panel to provide some actual protection. I may buy a replacement 25A breaker for the E-Panel. Thanks for the comment.

Steve

Horsefly · November 2016

Horsefly said:

Dave Angelini said:

The GFI is built -into the Schneider 60 amp and 80 amp controllers. I know the store here is very good with helping you find a solar panel that they sold you if they become unavailable during the early part of the warranty. My supplier does this with all of the equipment they sell me and any good dealer should take care of their customers.

Thanks Dave. At least that explains why MidNite Solar puts a GFI breaker in some diagrams and not in others. I thought I had read the install manual on the Schneider MPPT60-150 and don't recall seeing anything about it. I am still a little bit baffled by the concept though. In an ungrounded DC system like the battery bank and CC, what is the GFI protecting?

Steve

Actually, I just looked again and found it. It sounds like the Ground Fault protection in the CC is actually providing the negative to ground bond. So, even though I thought I had an ungrounded DC it is actually grounded via that GFP device. The manual then gives you instructions on how to disable the GFI if the ground bond is elsewhere in the system, or if it is a positive grounded system. Hmmmm...

Steve

Photowhit · November 2016

MIdnite started by making E-Panels to make wiring easier. Most (all?) come with diagrams and a place for GFI circuitry. Likely where you saw a diagram. The Midnite Classic has GFI built in and it can be disabled as you said.

The current NEC requires GFI (I think) If you are wiring to current code. And I believe requires systems to be grounded. I floated my current system for most of a year before driving in a grounding rod.

softdown · November 2016

OK....had the time to take a closer look at the schematic. Congrats....you just made many of us "old timers" a bit envious. I can understand the schematic but I sure could not make one like it.

This is much of the reason that I am going to stick to cabin solar installs, I am not geek/smart enough for the more involved wiring. When you first appeared on the board, the writing was on the wall. We could see this coming. You will have first class solar and a pretty significant investment. My intent is to install good, usable cabin solar for about $2000. You know....for normal folks.

I just got three strings, three charge controllers, one inverter , and three battery banks operational. That was about all that I presently feel comfortable with. Still....I check the batteries and charge controllers several times a day with knotted eyebrows. MacGyver would be proud. Some of our purists might throw me to the crocodiles. Three battery banks? Well....they were all used and I am cycling them a bit.

Dave Angelini · November 2016

Photowhit said:

MIdnite started by making E-Panels to make wiring easier. Most (all?) come with diagrams and a place for GFI circuitry. Likely where you saw a diagram. The Midnite Classic has GFI built in and it can be disabled as you said.

The current NEC requires GFI (I think) If you are wiring to current code. And I believe requires systems to be grounded. I floated my current system for most of a year before driving in a grounding rod.

And Outback and Schneider/xantrex/Trace were making distribution and DC panels long before that were also type accepted for code as a complete system. GFCI is required depending on the local AHJ and the owner if not inspected. Different parts of the US meet different requirements depending on what year of the code they require. My county is at 2010, barely....

Photowhit · November 2016

Dave, I don't think Trace/Xantrex made anything other than a DC disconnect for systems other than their own (I believe Robin had a hand in that, though I don't want to go back and reread the links), until they purchased Pulse Engineering's Power Centers PC-250 and PC-500. I had one up until a 3-4 years ago. Even that was only up to the current code in 1999. It did have AC and DC breakers, and a toggle for generator input and an integrated 60 amp charge controller.

Robin/boB also did one for Outback, but also Outback specific.

See a trend here? It's the same guys making them, but they chose to do one that would work for others. I know you like to stay within company, but these E-Panels were designed to use others equipment. I'm pretty happy with mine!

I went back and found a link to the original. It shows Robin with most of the things we've discussed.

Evolution of the E-Panel.

Dave Angelini · November 2016

I do not see your trend. If you think those guys are rock stars I am not going to spoil your dream, well maybe....
The truth in my mind is they were just engineers in a large group of engineers working for a corporation. I have been working with many of them for 35 + years.
I am not trying to minimize what they have done for themselves! it does not make sense to compare what is a system now and what was in 1990 when I installed and lived onTrace equipment.

I also would not mix up a system with components that are not tested as a system from the start. The same as mixing up different brands of equipment. None of those check marks on your link indicate to me that their panels are tested with the inverter to what an AHJ would want to see. The info is also very dated. New Outback/Schneider Ac distribution and Dc panels are mostly pre-wired to fully prewired.

It does not make sense to me to mix this up for a few bucks saved. When I buy a system for a customer, they get a better price as they are buying one system, with the solar and battery all in one sales order. They are designed to work as a system and there is data to show that to an AHJ.

For DIY without inspections they are fine! I use Outback Power Systems and Schneider Electric Solar systems. My bias!

Photowhit · November 2016

Dave Angelini said:

I do not see your trend.

Sorry, It's really a very small group of engineer's, not a huge market at the time. Not rockstars but likely the people who designed the stuff you were talking about... I've listened to a discussion with/by Heart Akerson about the very few people working on Solar/inverter industry back in the day. Got the idea you could fit them in a small room.

softdown · November 2016

Photowhit said:

Dave Angelini said:

I do not see your trend.

Sorry, It's really a very small group of engineer's, not a huge market at the time. Not rockstars but likely the people who designed the stuff you were talking about... I've listened to a discussion with/by Heart Akerson about the very few people working on Solar/inverter industry back in the day. Got the idea you could fit them in a small room.

Their history was recently posted and is quite interesting. It was the California marijuana growers providing the market that made their innovations possible. It is also the reason that I get a bit rankled by relentless attacks on MidNite. Their founders introduced the level of customer service that is still found at Outback and others. Not to mention being the pre-eminent solar pioneers.

We all bring different backgrounds and perspectives to the board. The broader the perspective, the deeper the insights.

Photowhit · November 2016

I don't think it's so much an attack, just a preference for a single manufacturer's system. Which put a lot of good companies out of the consideration. Magnum, (until recently, don't know that they make a breaker box yet), and Morningstar. The people at Midnite helped Outback through some tough times, they may still own a big piece of Outback. Midnite has or will have an inverter out shortly and more to follow.

I'll admit, when Midnite Classic was introduce, I was a big fan with out ever having one in my hand. I had suggested that measuring the charging current going into the battery bank would be a game changer. I was somewhat disappointed that when the whiz bang Jr was introduced it took a while to be fully integrated. I have one but when I received it the Classic was not ready to use the information that was collected. I can see where this would disappoint people, such as Handy Bob. I accept that it is pretty much a basic computer and must be updated. That peripherals will require tweaking. I just think it's different. I have no problem recommending Morningstar Charge controllers for people who want great working basic charge controlling, or Outback. I don't know enough about the new Schnieder, but suspect it's a good unit and does much if not all of what Midnight's do...

Now off to cut, split and stack wood,...lol. Joy's of off grid living. I really do enjoy it, for how many years we'll see. It's been the sunniest November in recent memory. Have dehydrator going (sweet potatoes) and crock pot (beans) water heater when sun hits panels fully in about 30 minutes andelectric chainsaw. Another 8-10kw usage day.

Dave Angelini · November 2016

Photowhit said:

Dave Angelini said:

I do not see your trend.

Sorry, It's really a very small group of engineer's, not a huge market at the time. Not rockstars but likely the people who designed the stuff you were talking about... I've listened to a discussion with/by Heart Akerson about the very few people working on Solar/inverter industry back in the day. Got the idea you could fit them in a small room.

I think you are right about back when Heart and Trace were starting in the early 90's/late80's
My point, when the century turned in 2000, Xantrex was not going to fit in a small room. There were many Engineers there! I know a bunch of them now at Schneider.
It was during the next 5 years that they developed the XW which in my mind still is the best Inverter. An all in one AC/DC distribution mostly pre-wired and their Mppt.
Outback during that time had the first Mppt and was starting to build very good systems. The folks who went out the back door were often on the old Xantrex user forum and I remember them being told that XW stands for Xantrex wins.

We used Trace at Hewlett Packard in some of the power systems I worked on. The California pot industry then was mostly all smuggling across the border. Very few growers in the 80's and into the 90's. I lived there and remember using the gear then as an engineer.

The OP here will do what he wants to in the end. Mixing up equipment and saving every penny is something I don't do. It often does not save much and makes things difficult for others who do not have the time for this.
What the heck go for it. Life is too short to take this stuff too seriously. I am just trolling anyways!

I do wish Midnite good luck with their first Inverter!

softdown · November 2016

The OP is, I believe, a retired electrical engineer. Plenty of time and perhaps a tiny bit of ego involved. Would not be surprised if he stumbled upon a superior system. Innovation is done by trial and error. I think Edison failed over a thousand times before making a successful light bulb. Pretty worthwhile innovation...

My late uncle made an LED clock in the early 70's. Not to save money....for the challenge and possibly to prove something. Some of his software is still used by power companies. The royalties augmented certain things....I believe,

Horsefly · November 2016

I'm just now catching up with what looks like lots more conversation than I would have anticipated. To be honest, I'm not too sure how to interpret most of it. I think the historical links between all these companies that now build solar components is pretty interesting. I don't have enough history (none, actually!) in all this to have any skin in the game.

Through the course of lots and lots of web pages (including this thread), I determined that we would probably be served well by choosing a CC and Inverter from the same company, and hopefully get a control panel that worked with both at the same time. That seemed to lead me to either Outback, Magnum, or Schneider. Outback seems to get lots more comments in places like this, and may be used more by DIY'ers. I don't really know. Magnum seemed like good stuff, but was fairly expensive. When I saw the Schneider MPPT-60-150 and the SW4024 Inverter, everything I read was pretty good. The Schneider System Control Panel is really sweet, and seems to be more likely to be acceptable to the non-hobbyist members of my family. The fact that MidNite Solar made an E-Panel specifically for the SW4024 (taking the place of Schneider's separate DC panel and AC panel, saving more $$) was icing on the cake. The fact that this set of equipment was cheaper than I could find for either Outback or Magnum was the final point.

I'm hoping that using stuff that seems to be all designed to work together will help me avoid OEMs from pointing fingers at each other when something doesn't work.

At this point I'm kind of committed to the parts I've selected, since UPS is delivering them tomorrow. Still, I'm keen to learn, so if I can take some of what you guys are saying as something I can learn from, I will gladly do so.

Hey @softdown: Interesting to hear about your uncle. I too built an LED clock of my own design in the 70's, when I was in High School. I guess my path was already laid out by then!

Steve

mike95490 · November 2016

Here's my well pump motor power chart:
is your pump a 2 or 3 wire (starting cap in the well = 2 wire, up top =3 wire)

Image: https://us.v-cdn.net/6024911/uploads/editor/b4/xpwow4hk05qh.jpg

softdown · November 2016

High school in the 70's? Already retired? I graduated high school in '76, college in '80. Looong way from permanent retirement.

Horsefly · November 2016

mike95490 said:

Here's my well pump motor power chart:
is your pump a 2 or 3 wire (starting cap in the well = 2 wire, up top =3 wire)

Sorry @mike95490, I didn't notice your post.

My pump is 2 wire, 120V, and we know it's running current is between 12A and 14A. I'm hoping the inrush current isn't 55A (yikes!), and I'm pretty sure it isn't. Our old generator was a 5kW Honda, and our newer one is a 7.5kW Westinghouse. With the old generator, there was a slight but noticeable drag for a split second when the pump first turned on. The engine had a slightly different running sound for a second, and if you were watching very carefully you might be able to notice any incandescent lights would dim for a split second. With the new generator, there is no noticeable change when the pump starts. The engine stays steady and the lights don't dim. The old generator was a nice one but was probably purchased in 1979 or so, and may have been a little inefficient. The new one was purchased about 2.5 years ago. Anyway, based on this very unscientific data I would guess the inrush / startup power of the pump was not over 5kW, but is well under 7.5kW.

The pump guy who has helped us a few times (but hasn't actually pulled the pump) thinks that its likely to have a inrush current of 18A to 21A. The pump is only about 40-45 feet down from the surface, and the horizontal run to the cabin pressure tank is about 150 feet, so I don't think the pump has to work real hard. If the inrush current is 21A that's only about 2500W. Even if it is 30A (3600W) we should be fine with our 3500W inverter, which has a 5 second surge capacity of 7000W.

Steve

Horsefly · November 2016

Hello everyone. Me again.

Although it will be next May before we actually start on much, I've been starting to think about our pole mount for the panels. We will be doing it ourselves, rather than buying a ready-built contraption.

I'm mostly wondering about structural stuff. We don't get much wind up where our cabin is, but we do get some snow. In looking at the commercial pole-mount units, it seems like they all say we need a six inch pole, but we were planning on using a four inch well casing. Are there some sort of standards in this stuff? We're about 20 miles from any paved road and not of much interest to building inspectors, but I'd just as soon do what is smart.

If anyone has some PDFs they can point me to, I'd appreciate it!

Steve

westbranch · November 2016

How many panels ? Dimensions of array? PV Weight? dont forget about the cement ballast....lots of other designs other than top-of-pole...

Horsefly · November 2016

westbranch said:

How many panels ? Dimensions of array? PV Weight? dont forget about the cement ballast....lots of other designs other than top-of-pole...

Well, since we aren't doing the bulk of the work until late spring, we're not buying the panels for quite a while. If we go with what I've planned for now, it's 4 72-cell SolarWorld 340W XL panels. They're pretty big, like almost 79" by almost 40", so I'm assuming the total would be around 80" by something over 160". That's pretty big, so we are thinking about two 4" pipes, maybe 8 feet apart. It would be better if we could do with just one, but that may be a bit much.

littleharbor2 · November 2016

You can configure differently and get about 120" x 120".

Horsefly · November 2016

littleharbor2 said:

You can configure differently and get about 120" x 120".

Thanks @littleharbor2, you are right. I guess that might be better if we want to keep it on one pole.

Since we don't really know what panels we will end up getting, we may get some of the more square Kyocera panels (66" by 52").

westbranch · November 2016

Now you are getting into voltage loss in the wiring...How far away from the CC will the panels be and then how far to the battery and then to the inverter? which CC will match up to the panels, or visa versa, if in SERIES. without going into (winter) Hyper-voltage? this can be a major decision breaker with a smallish system

Horsefly · November 2016

westbranch said:

Now you are getting into voltage loss in the wiring...How far away from the CC will the panels be and then how far to the battery and then to the inverter? which CC will match up to the panels, or visa versa, if in SERIES. without going into (winter) Hyper-voltage? this can be a major decision breaker with a smallish system

@westbranch: Hopefully we are well past all that. I'm doing 2 x 2 (2 strings of 2 in parallel), which keeps me well below the temperature adjusted Voc limits for the CC. I've done all the math on voltage drop on my wiring to the CC, and I've got a little less than 3% drop. At this point I'm really just talking about the mounting of the panels.

westbranch · November 2016

Huh ?????
Since we don't really know what panels we will end up getting, we may get some of the more square Kyocera panels (66" by 52").
vs
I've done all the math on voltage drop on my wiring to the CC, and I've got a little less than 3% drop.... (Good, but it should be 3% all the way to the batteries.)
hth

Mountain cabin off-grid

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