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Small Cabin Forum / Off-Grid Living / Thinking about solar elec again
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gcrank1
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# Posted: 24 Feb 2024 01:19pm
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I took mine all down fall of '21? knowing it all needed to be rebuilt. With 2x12v LFP we didn't really need to charge at the cabin so I just rotated in use and took one home to charge. With the new cabin coming in spring Im planning ahead...
I know I need to avoid any shading!
With only 6x100w panels and a 50a mppt scc I can keep our 200ah of 12v bats charged for our useage.
We dislike the look of ground mount panels at our place, they clash with the rustic nature of the place.
The cabin roof ridge runs N/S with good expose to the E, tall white pines right at the W. And Im not in any kind of age or condition to be messing about on a roof.
Directly S of the cabin is where the woodlot starts and goes W so really anywhere in the meadow is at best a S/SE exposure, again on the ground.
But a good 100yd to the E side of the meadow is a bit of a hill with some pines and great S exposure. Im thinking I can 'hide' the ground mount array at the pines. Thing is, there is no way Im going to run the array wires all the way to the toolshed/powerhouse to scc/bats/inverter for the 50' run to the cabin.
So, it looks like build a 'power shack' atop the hill with the array to run 120vac to the cabin. Im iffy about the security/potential loss of all that stuff, inc the LFP bats! And Id still have to trench and use expensive underground feeder wire.
It is looking like maybe I should make a smallish weathertight 'cart' with a plug and play scc and bat box to roll up there when Id swap in the full charge bat at the cabin with the psw inverter there.
A little futzy but practical I think.

Steve_S
Member
# Posted: 24 Feb 2024 01:51pm
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I dunno about 100W panels.

I just installed a system for a neighbour which may give you an idea.
2x Q-Cell 405W panels (monofacial) on a pole mount.
1 Midnite Kidd producing 30A for 24V Battery.
1 APC 3024 Inverter/Charger 3000W LF, can charge @ 45A.
2 24V/175AH LFP Packs. (250AH total)

The 2 Q-Cells are the MAX the Kidd can take and honestly it's way overpriced because of the extra features & functions.

With your existing 50A Controller it likely could handle 3 or 4 Larger panels and generate closer to the 50A output while keeping it "tidy". With a 50A charger you'd have no problem keeping those batteries up because you are quite a frugal power user already.

Just a thought about your description and panel placement... You can have a couple on the East & a couple on the South to capture morning through to early afternoon.

No mention if you'll have a gazebo, carport, or toolshed etc... which may be tweaked to use solar panels. Just some possibilities as this is a fresh build. Solar Roofed Porch ? hahaha, sorry couldn't help it.

gcrank1
Member
# Posted: 24 Feb 2024 02:30pm - Edited by: gcrank1
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Hi Steve, Always glad to have your input!
My 6x100w'ers date back to at least 2012. They were (as far as Ive been able to find out) pretty decent panels at the time, they are still are in good shape and I checked them individually for output, they hit spec.
But yeah, they are old, and 6 to mount for their now limited capability.....
I have a friend nearby who bought a couple? pallets of higher output panels, I should check the specs, maybe they will work with my scc (it too was a pretty decent one at the time). Mounting a couple would beat mounting 6.
at my proposed hill location I could do one side a bit S/SE and the other anywhere S to S/SW to even W to good effect. But wouldn't that mean Id need another scc as the more easterly panels fade out?

Brettny
Member
# Posted: 24 Feb 2024 03:41pm
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Have you thought about paying someone to roof mount the pannels? It may be cheaper in the end vs hundreds of feet of wire and the cost of a ground mount.

gcrank1
Member
# Posted: 24 Feb 2024 04:04pm
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I don't really like the idea of perf'ing my brand new metal roof and it would only get me a due E exposure and about 1/2 the angle on the roof proper. If I had decent S exposure on the structure Id think more about a close to the wall mount IF I had a long wall on that S side, which I won't.
The long wire run from the hill isn't likely to happen and my ground mount would be pt posts and 2x's for the few panel array I have. All low buck, but sturdy enough.
Weigh all this against my est of $3500ih to grid hook and a monthly bill......about $30ish of that at today's rates for the privilege of being hooked up for $5 worth of elec.

Nobadays
Member
# Posted: 24 Feb 2024 05:06pm
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A 300' run of 120vac will require sizable cable to prevent drastic line loss/voltage drop. I ran a quick calculation and 10awg would result in over 10% loss of voltage. To keep it to ~2% you would need 2awg copper conductors. That's a ton of money in cable!

Any way you could back a ground mount up to trees/bushes near the cabin to help "hide" it a little?

gcrank1
Member
# Posted: 24 Feb 2024 06:19pm
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Thanx for that cable info.
Believe me, Ive thought thru and even experimented in diff spots with my portable set up. No way to 'hide' an array anywhere close to the cabin.
That does bring up that I could do a small trailer mount array that I could just pull and park when needed then tuck it back into the woods behind my toolshed.

ICC
Member
# Posted: 24 Feb 2024 06:28pm
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There are special solar mount brackets that are installed on the ribs of a metal roof. I believe they are available in a few profiles that match pretty much every brand of metal roof sold in the US. They come with epdm gaskets applied. Screws go through the sides of the ribs. A friend who started a solar company about 20 years ago has been using them for years and says they have never had any problems. The solar panels mount directly to the rib mounts so there are no rails needed.


I have a 330-foot run from the most suitable PV panel location to our cabin. For me I calculated that it was better to run the DC from the panels to the cabin where the batteries and the inverter would be. There are some variables that may make this good or bad or little difference.

I wanted to be able to run at least 15 amps of 120 VAC power without significant voltage drop. I use a \n 1100 watt microwave, a toaster oven, a Vitamix blender, and other appliances at times.

I also did not want the batteries 330 feet down a slope that could be difficult to traverse with a foot or more of snow on the ground. That was 15 years ago when I was still ready to snowshoe 7200 feet through whatever snow had fallen.

I ran the DC power from the 640 watts of panels connected in series to minimize the amps. That still needed 6 AWG wire to keep the drop under 2.5%. To have 15 amps of 120 VAC would have needed 4 AWG wire to keep the drop below 3%.

I guess everything would be different if no more than 5 amps of 120 VAC was needed. But I still don't like the idea of the batteries and the inverter being 330 feet distant.

Different strokes...

ICC
Member
# Posted: 24 Feb 2024 06:29pm
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Oh, and I figure that solar panels are simply a part of modern day life.

travellerw
Member
# Posted: 24 Feb 2024 06:59pm
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Ok.. Now hear me out (since I usually would never suggest a series arrangement).

I would look on Facebook market place for new panels. Around here there are some fantastic deals on new panels (550W bifacial for like $220cdn). The higher the voltage the better for you (most are about 50 VOC). Buy 5 and wire them in series (so 250 VOC), then you can get away with like 4 AWG. If you buy 6, you can probably run 6 AWG.

You will need to make sure you minimize shading, and be super careful (300V DC will kill you FAST, and hurt the whole time). Blankets or cardboard over the whole system until you are ready to go live.

If you look for used panels, you may even get a better deal. The panels I bought were from a solar farm that had a ground fire. It burnt a section of panels, so the insurance company scrapped everything and installed all new. I bought mine for pretty damn cheap!

Brettny
Member
# Posted: 25 Feb 2024 06:37am
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$3500 to hook to the grid? Pay the $3500 and not worry about any of this. Also makes the place more valuable.

FishHog
Member
# Posted: 25 Feb 2024 08:03am
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Quoting: Brettny
$3500 to hook to the grid? Pay the $3500 and not worry about any of this. Also makes the place more valuabl


Have to agree with this. Seems like a no brainer to me

paulz
Member
# Posted: 25 Feb 2024 09:16am - Edited by: paulz
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Will you not have any other external structures, carport, storage shed, awning? My panels are on the sunny side of a storage shed 50’ from the cabin, ground to roof ridge, and three more on a rain/sun shade on the deck outside the cabin door.

Or cough up the $3,500.. I don’t know, I could get grid power too but it might take some of the DIY/self sustainability and fun out of the whole cabin experience. It is ‘fun’ isn’t it?
IMG_1748.jpeg
IMG_1748.jpeg


ICC
Member
# Posted: 25 Feb 2024 09:23am - Edited by: ICC
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$3500 for a grid tie is a fair price. It is only part of the cost though.

For that to happen the new cabin would almost certainly need to be wired to meet all the electrical code rules. Probably 100 amp 240 VAC service minimum.

travellerw
Member
# Posted: 25 Feb 2024 02:05pm
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Holy crap $3500.. I only wished.. My quote was $21,000 to the property line. Then it was my responsibility to take it the 300 yards on my property.

I wouldn't even hesitate at $3500...

gcrank1
Member
# Posted: 25 Feb 2024 03:18pm
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No Paul, nothing else but my barn roofed 10x16 prebuilt toolshed with the roof the wrong way and not in good exposure either. If I do a 'carport' type for my tractor it will be further into the trees.
Like you Im into the off-grid self sufficiency mindset, for good or ill I guess....
Agree that the hardwired cabin would likely cause me some code issues, and really overkill for 'our' needs.
The addition would be an enhancement to the resale value but the best place to build a house isn't where we have the cabin. Running 'real power' to what ultimately may be the wrong spot may not be a good idea.

paulz
Member
# Posted: 25 Feb 2024 05:41pm
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Here’s the front of my cabin (still a mess from the storms) showing the rain/sun shade made from panels. Just a few feet of 2x4 framing.

The shed with the main panels is visible above right.
IMG_2244.jpeg
IMG_2244.jpeg


Brettny
Member
# Posted: 25 Feb 2024 08:33pm
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Quoting: gcrank1
Like you Im into the off-grid self sufficiency mindset, for good or ill I guess....

You could change that to the offgrid backup system.

Also if you run a power pole with a meter and main panel on it you could just plug your cabin into it.

Any power even at the wrong build site is a benefit at time of sale.

gcrank1
Member
# Posted: 25 Feb 2024 09:26pm - Edited by: gcrank1
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Here they only do underground feeders to an 'approved' meter stand with the meter box and service box (best I know for the terms). A local fellow doing a build told me all in to his 'plug & play' was about $2500 and he is faarrr shorter to the line pole than I am.
If I had no power at all now and needed to buy even what solar I have, the gen and batteries the grid expenses would seem more attractive. It sure would if we were four-season or full time!

redwolfguild
Member
# Posted: 26 Feb 2024 03:19pm - Edited by: redwolfguild
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gcrank1 -

I know you said you don't like ground mount, but I am with you, no way am I putting holes in my metal roof. I can't remember from your previous posts of your power needs but I use 2-210 watt solar panel that I ground mounted. It keeps my 200 amp Lithium 12 volt battery topped off all the time. I only run a 800 watt inverter for the fridge and Starlink when I am at the cabin and have not used the generator once since I switched. Panel is only about 60 feet from the MPPT CC and I used 10 AWG as it runs at 48-50 volts. Just my $.02

gcrank1
Member
# Posted: 27 Feb 2024 10:19am
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I have 6x100w panels about 12-15? years old, nicely built, solid units. Bet they cost the prev owner a good penny.
He had them run as 2s/3p into a Blue Sky 50a mppt 12/24v sec, then into 4 huge ups 12vx120ah agm batteries all Poorly wired in parallel. That 600w of solar should have kept those charged well enough for his very moderate usage, and ours. But he had the +/- from the scc coming in one end of the parallel bat-bank and the +/- to the 1000w inverter out the last battery.
Oh, those poor batteries.....the farther down the line the less charge they got. After load testing and weeding out the worst 2 I still got 1-1.5 years more out of the slowly failing remaining 2.
Yes, I could put the array 50-80' away from the cabin and get morning thru 3pm exposure. But that atrocity of an array in the midst of our meadow would more than bother me (us) in spite of its practicality.
By my calc of our typical 24hr daily elec usage I could probably run my little 2000w gen 1/2hr a day for the big charger and keep my 2x100ah lfp bats decently topped up. Ive yet to try that as one bat has happily kept us in power for a week of off/on use. I just swap in the other and take the low one home to charge.
But who wants to listen to a gen? Not all day or night like some do at their place; I don't know how people do that! 1/2-1hr sometime during the day with a very quiet small inv/gen is no big deal. For me, not near as vexing as seeing an array in my meadow.
Now if they would make hooking up an EV (or better yet for me a Hybrid) to the cabin easy Id consider that for my next car; I think that would be a dandy set up.

travellerw
Member
# Posted: 27 Feb 2024 10:45am
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Quoting: gcrank1
Now if they would make hooking up an EV (or better yet for me a Hybrid) to the cabin easy Id consider that for my next car; I think that would be a dandy set up.


This is where grid power is required as the math just doesn't work out for solar. We have the slowest charging Tesla (32A @ 220V) and that gives us 27 miles per hour of charging. That would require a constant feed of 7000W of solar to supply that power. A 10000W (remember losses) array could probably provide that for 3-4 hours on a sunny day. You would still need a battery (a big one) to provide a buffer for shading. That is a whole ton of equipment and expense to get like 100 miles of range/day.

Of course you can bump things down, or even charge on 110V, but then we are talking like 4 miles per hour of charging. Tesla is one of the most efficient and uses the least amount of KW/M, so other cars would even have worse numbers.

This is why its silly when you see companies putting panels on the roof of their cars (looking at you Fiskars). The Fiskars Ocean has panels on the roof that will add 7000 miles of range OVER THE LIFE OF THE CAR in sunny locations.

paulz
Member
# Posted: 27 Feb 2024 11:54am - Edited by: paulz
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Quoting: gcrank1
if they would make hooking up an EV (or better yet for me a Hybrid) to the cabin easy Id consider that for my next car; I think that would be a dandy set up


How about the opposite? The cabin is only 25 miles from my grid house. I drive my old, 14mpg pickup. If I get an EV, could it be used to power the cabin bank much, and still get back to the grid?

travellerw
Member
# Posted: 27 Feb 2024 11:59am
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Quoting: paulz
ow about the opposite? The cabin is only 25 miles from my grid house. I drive my old, 14mpg pickup. If I get an EV, could it be used to power the cabin bank much, and still get back to the grid?


Tesla Cybertruck, Ford F150 Lightening, Hyundai (all electric models), Kia (all electric models) can all do this. They provide between 7-12KW.

gcrank1
Member
# Posted: 27 Feb 2024 12:06pm
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Our grid rates, at least for now, and all in with the 'extra' charges they itemize in, is still pretty reasonable/even cheap compared to many.
My best plan at this point would be home grid hybrid recharge and just plug it into the cabin for power (If they actually make bi-directional), no recharging there.
An suv or even minivan would be better for me too.
I heard last week that Ford has lost ten's of thousands of dollars on every EV they have sold and the idea of 'don't park near anything flammable' does put me off.
I think it is going to be a good while before this is really a viable alternative for most people.

travellerw
Member
# Posted: 27 Feb 2024 12:43pm
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Quoting: gcrank1
I heard last week that Ford has lost ten's of thousands of dollars on every EV they have sold and the idea of 'don't park near anything flammable' does put me off.


This is because Ford, GM and others are stuck in their old ways. They are trying to make EVs but keeping to their old methods. It just doesn't work with EVs as different methods/materials must be used. This is just as analysts predicted 5 years ago. The big guys will struggle to make profitable EVs.

As to the catching fire thing.. Pure garbage. While thermal runaway can/does happen, its super rare. If you see a pack tore down it will make sense. They are engineered with fire suppressant foams and shields to prevent that. Personally, I'm much more scared of being caught in an ICE vehicle if it catches fire than an EV. If an EV pack does run away, it burns slowly over many hours, unlike gasoline.

Hyundai/Kia have gone all in and have some pretty good vehicles. The Ionic 5 and EV6 are damn nice cars. Of course a Tesla Model Y is also great too. Unfortunately the company leader brings the brand down. All those are considered SUVs.

We have owned our Tesla 2 winters now, with sints of -40C. While we loose %50 range at those temps, the car is amazing. Its the warmest (interior) car I have ever owned.

ICC
Member
# Posted: 27 Feb 2024 03:37pm
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EV fires do not concern me. The Media makes a big splash whenever one burns and completely ignores all the ICE vehicle fires.

And I am not too concerned about Ford or GM losing money. If they can't learn the new tricks that is their fault, not mine. Twenty years ago I never thought I'd agree that Hyundai made some good vehicles.

I enjoyed my Tesla for the two years I had it. I charged it at home off the solar. The main criticism I had was not Tesla's fault. It was the poor public recharge system here in NM. Even along the interstates, a couple of stretches still require forethought that one does not need with an ICE. I had a chance to sell my Tesla and come out even$$ and so I did. Elon did not help me have any brand loyalty.

Now I have a '22 Volvo XC60 as my most used non-truck vehicle. It's a plugin hybrid. I don't worry about highway trip charge stops anymore. It regenerates well on the downside of the mountain hills and works nicely in one-pedal mode. The available 455 hp is cool too. I'd give a pure EV another chance once the public recharge stations are more numerous in NM. Or if I lived in or near one of the larger population centers, the Tesla could still be a viable vehicle. I have friends with E's who love them and have sworn they will never own another ICE vehicle.

Using an EV as the power source for a cabin should work out well in many cases. It depends on the distance from home to the cabin and then being a minimalist power user at the cabin.

gcrank1
Member
# Posted: 27 Feb 2024 04:00pm
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455 HP !!! Yowza
I think once we have perhaps the next generation of batteries; ie, the big leap forward like LFP is over LA, that EV's might take off. Well, if the price can be sensible....
We used to drive Toyota's, then switched to Suzuki based, a few stumbles back into 'the Big Three' and Kia's for some years now (a 2008 2wd Sportage and 2, or is it 3, Soul's). The Kia's have been Very Good to us, all ICE, typically the 4cyl Soul's have been 30mpg+; the worst in winter.
Do the 4wd EV's still run through a transfer case, etc?

ICC
Member
# Posted: 27 Feb 2024 08:35pm
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Quoting: gcrank1
455 HP !!! Yowza


Not every model of the XC60 has the 455 hp engine.

The terminology, AWD, 4x4, 4WD can get confusing. Then it gets more interesting when EV's are thrown into the mix with ICE and hybrids. (And a motor uses electricity while an engine burns a fuel and some people confuse motors with engines too.)

The XC60 Recharge (the hybrid) has AWD. No center differential, no transfer case. The ICE engine drives he front wheels and the high-voltage electric generator. The rear wheels are turned by an electric motor. The front wheels are powered by the ICE engine. In electric-only mode only the rear wheels power the car. Good for maybe 35 miles. In regular hybrid mode the rear wheel electric motor apply power as needed (determined by the control computer and pressure on the gas pedal), while the ICE does more of the work. The rear wheels also supply regenerative power when braking/slowing. That works very well and allows driving with only the one pedal; press down to go and lift up to slow. Takes getting used to as there is no lifting your foot and coasting to a stop.

The ICE only version of the same car can be had as an AWD or a front-wheel drive only. The AWD has a center diff and front and rear diffs, but no transfer case as we would expect in a conventional 4x4 with a hi-lo transfer case. All wheels are powered at all times; AWD.

An AWD Tesla has 2 motors, one for front wheels and another for rear wheels. An AWD RAV4 hybrid has two motors (F&R) plus the engine. Neither has any direct connection between front and rear motors other than the wires and control system.

A standard EV has a one speed reduction gear transmission. There's a Porsche EV that has a 2-speed transmission. A hybrid has a more normal multispeed transmission for when the ICE is delivering power to the wheels. The XC60 has 8 speeds fwd.


I don't know of any EV's that have a conventional 4x4 system with a low-range t-case. Too much friction with all the gears that would require I suspect. Plus electric motors have nearly full instant torque from zero RPM so they normally don't require extra low gearing, although I think an electric rock crawler buggy would be cool.

gcrank1
Member
# Posted: 27 Feb 2024 08:42pm
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Just read on diysolarforums.com that with an array farther away it can be better to run the dc and eat the losses than invert at the array and Have To Have the larger cables to carry the ac to keep losses under 3%.
The dc can be better because the inverter will just invert whatever gets delivered, the losses are just lost.
Of course the higher the voltage the smaller the wires can be, Id be better off with a 48v (or more) system but I currently have 24v input for the mppt to send 12v to my bats.

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