Some thoughts/suggestion for Solar pv set up? Please??

Howdy folks!

My first post here as I didn't see an Intro thread. I'd seen quite few of Paul's vids and finally decided to pop in at Permies after watching his scythe sharpening vid.

I'm planning to go off grid since I just don't wanna fuss with all the crap and expense (like $2k +) of getting grid power onto the property and hooked up to the as yet unbuilt house. I'm scoping out the major components for a PV system and would like some feed back on a few things, if anyone would be so kind.

We'll be building as energy efficient as humanly possible. The property is in central Maine on a gently sloping, SE facing, 7 ac lot that is now a fallow hay field, so no trees to interfere. We're wide open to the south. The house will be positioned accordingly and within about 100 feet +/- of the forest on our north boundary.

I'm planning a 24 x 24 two story with basement (1728 total sg ft 1152 sq ft of living space) and as much glass on the south face as I get fit in as well as an atrium/solarium ground to roof for winter salad growing and passive solar heat. Thinking about TM options for storing all that free heat too. Will also be installing an under floor heating system using a wood fired heater (a dbl barrel stove) with LPG back up. Eventually there will be solar air and water collectors built and put into the mix as well as a DIY VAWT or two. Winter is windy in Maine.

The only major electron eaters will be the well pump, fridge and freezer all of which will be new and energy star rated. I'm aiming for 1kw/day or less. Sorry if that's the wrong unit of measurement, still spooling up on this deal.

I found a few things on Amazon that looks like it will easily suit my needs (and wallet) and allow some expansion.

-TRACER 3215RN 30A MPPT Solar Charge Controller
-DECEN 1000W 24VDC/110VAC Peak Power 2000W Off-grid Pure Sine Wave Solar Inverter or Wind Inverter 60Hz

And I'm liking the 250W PV panels they have as I can buy a couple at at im and expand as I have money.
RENOGY® 250W Watt Monocrystalline Black Solar Panel UL Listed

At 4350 each I could only buy 1 at a time, but I'll be in a camper using very little electricity until the house is up and we'll have a generator to run the power tools.


Would appreciate your thoughts and suggestions.
Tim

The unit of measurement would be kWh; 1 thousand watts for 1 hour.

Hi Tim, welcome to Permies!

Sounds like your site is well suited to solar. However, several pieces of the puzzle should really come before component selection IMO.

1) First step is to get a real number for usage. I think your goal of 1kWh per day is rather optimistic if you're talking a standard house-size fridge, and a standalone chest freezer.

Below is an article on freezer relative efficiency, which also provides an idea of energy consumption. The low end of the energy consumption scale seems to be barely below 365kWh per year, AKA very nearly 1 kWh per day. Note that these is actually quite a bit less efficient in terms of watts/cubic feet than the larger ones.
http://labs21.lbl.gov/wiki/equipment/index.php/Recommended_Residential_Freezers

A standard size fridge comes out at similar consumption, putting you way over 1kWh per day already. You might look into converting a chest freezer to a fridge for improved efficiency.
http://www.aselfsufficientlife.com/chest-freezer-to-fridge-conversion-the-most-energy-efficient-fridge-ever.html

Well pump will be totally dependent on water consumption, but you should be be able to guestimate this with a bit of legwork.

Who will be living in the house? What other sources of power consumption? Lighting, fans? Electronics? Make a list, round up on everything.


2) How much power is there to collect? Look up the annual hours of sunshine for your area. With that in hand, figure out how many hours of sun you can expect in the winter, since this will be the bottleneck.

3) How long will you have to last on batteries? Is it normal to have a week or two of essentially no sun, often? Or would more than 2 grey days in a row be astonishing?

4) I assume the generator you mention will be available for a backup source? You'll need to decide how important it is to you to avoid using this, since this is a major part of sizing the solar system.


Once you know all that stuff, you can begin to estimate your requirements, and either adjust your goals, or begin selecting equipment.

As far as equipment goes, you do generally get what you pay for, or maybe a bit less. An inverter or charge controller that goes bad can take out your much more expensive appliances or batteries...

Don't forget to allow for conversion losses, use adequate wiring, and to size the battery banks to allow discharge to an appropriate level for long life. Be prepared to think of that $2000 connection cost as very cheap!

How much KWhr are you currently using per month right now. That is going to be your real number.

I do think that 3KWHr per day is doable.

For that you are going to need
six 250W solar panel ($1500) (there is a 50% loss of power)
one 2000W inverter ($1700) (it needs to be pure sine wave if you are going to have laptop, electronic, LED tv)
one MPPT charge controller ($600)
one 8KWHr battery storage ($1200) (this will cover you for 2 cloudy days)
one 1KWHr emergency generator ($1200) (Something will go wrong and then you want to make sure you can get drinking water)
mounting, electrical wires, fuses, switch, etc ($600)
$7000 with you doing all the labor.

Thanks fellas.

Right now our consumption will be minimal. We'll be starting out in a camper with a fridge and a couple lights, the laptops & mobile phones and maybe some TV in the evenings. I'm thinking next summer before I can put up anything livable.

I'll get a better working number for kwh when we get Stateside in a couple months and can put hands and eyeballs on some data tags. I do have a little money to work with but that $2k up front price tag just to get the grid on my side of the road is over the top. Looking at prices on the web I can get a working PV system for less than that and it'd be spread out so the sticker shock ain't so bad. I figure for the camper I can get by on a system with two 250 w panels and expand it over the following few months to that 2000-3000 w system mentioned in another post above.

I suppose I should mention that I used to work as a lectrician in my youth and still remember how to keep the magic smoke inside the wire. I won't kill myself or burn the ranch down.

Right now I'd like to get some input from the collective on the components and see what I can do relatively quickly and add to as I go.

I like the looks of these panels and I'm getting the impression that Renogy makes good stuff.
http://www.amazon.com/dp/B00F9HUXWO/ref=wl_it_dp_o_pC_nS_img?_encoding=UTF8&colid=1US2YWABWOR6P&coliid=IF3K3VS9YW0AL&psc=1

This MPPT looks like it'll do us for a while.
http://www.amazon.com/dp/B00E7NI9PE/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=1US2YWABWOR6P&coliid=I1DKZ3MA331LXB&psc=1

And sticking with the Renogy line I found this inverter.
http://www.amazon.com/RENOGY%C2%AE-Battery-Inverter-1000W-12Volts/dp/B00GWCEZ60/ref=pd_sim_sbs_lg_4?ie=UTF8&refRID=0J1FWZEQ8TNRZYJTVC9D

I'm ready to pull the trigger on the MPPT or the Inverter right now and will start grabbing a panel a month after that, I might bite the bullet and go for 2 panels first then nab some batteries.

BATTERIES
I know to NOT use automotive. I see lots of folks use the golf cart 6v. Do I understand right they're deep cycling like the marine (trolling motor) batteries I see everywhere and have used in the past? Is there any reason not to use a 12 v marine deep cycling batt? I handled a lot of Optimas in my final years in the USAF and know they're pretty solid units and would be willing to spring for them. The marine units are going for $200 each at Sams right now, but Duracell GC batts look reasonable.

For now I simply don't have the jack to go for forklift batteries, but I sure would like to some time down the not too distant future road.

Hi Tim,

Determining your requirements is really key to selecting components, but I can at least make some general observations:

1) If you want to expand later, you'll either be replacing all your components, or buying capable enough components up front to handle your eventual needs once more batteries and panels are added; I would be inclined to the latter. If you'll ultimately need a 2000W inverter and 1500W of panels, a 1000W inverter plus a controller that will handle ~780W of panels are not exactly optimal.

2) I would prefer LiFePO4 or NiFe batteries to lead-acid of any sort, but these will be expensive up front. A good option IMO would be to invest in a solid inverter and charge controller, get a minimal bank of cheapish batteries, and keep adding panels until you have enough. Then upgrade to a better battery bank as funds and requirements line up.

As far as 12V batteries go, there are arguments for both parallel and series configurations, and your voltage choice will influence your options there... but for a smallish, cheapish, short-term-ish bank a pair of 12V cells seems fine to me.

3) I have no familiarity with it, but that inverter seems suspiciously cheap to me... I'm leaning towards a Go Power pure sine model as a cheaper alternative to what I'd really like, which is Victron Phoenix gear.

4) I have heard it argued that MPPT is no longer worth the expense due to the current low prices of panels; something to consider.

The inverter only allows a 12V battery system and not a 24V battery system. SADLY this means that the solar panel charge controller will be limited to an input of just 400W and not 800W aka just one solar panel (250W).

At the very least you are going to need different inverted to make your tiny 1KWHr system work.

I've never quite understood why off-grid people think that they need to have a refrigerator and freezer. They are two applications that take a lot of high-powered electricity to accomplish. And what is achieved for the expenditure? An ability to store ketchup, mayonnaise, and leftovers in the fridge and meat in the freezer. The refrigerator can be eliminated by planning to cook only enough food for a meal, using non-perishable condiments, eating vegetables and staples instead of processed food, etc. There are other ways of preserving meat and vegetables that don't require on-going expenditures of electricity.

I haven't done the math exactly, but using electricity to heat/cool has got to be one of the dumbest ideas that industrial civilization ever came up with. I really think that people that are living off-grid aught to seriously consider whether or not they really need refrigerated or frozen food storage. Electricity is great for lighting, and running electronics. It sucks for heating/cooling.

@Dillan

1) If you want to expand later, you'll either be replacing all your components, or buying capable enough components up front to handle your eventual needs once more batteries and panels are added; I would be inclined to the latter.

YAHTZEE!! Given my current finances that's how I'm going to have to proceed.

And DAYEM them Go Powers ain't cheap either!

And yes, LA batts are going to have to do me for the foreseeable future until I can upgrade. The plus for them is they're cheap and I can stash them and put em into service when the old bank has dropped off in performance. Sam's has Duracells for ~$85 each. Oddly enough they have a MUCH better Amphr rating than the other more expensive ones.

Thisun is a real cheapo, I know, but it does handle 24 vdc. If it holds up for a year I'd feel like I got my money's worth and could save up my kopeks to get a better rig. And if it doesn't puss out on me I could always use it for speriments on the vawt rigs I want to tinker with.
http://www.amazon.com/dp/B00QPRZYOO/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=1US2YWABWOR6P&coliid=I26FDRY32CRKT

This one might be more robust and the input & outputs can be customized. For a little more $$ they have a 48vdc model too.
http://www.amazon.com/Nimble-NR1500-Off-grid-Inverter-Solar/dp/B00P7JD8D0/ref=sr_1_11?s=lawn-garden&ie=UTF8&qid=1431240547&sr=1-11&keywords=24+vdc+inverter

@Benji
Thanks for pointing that inverter voltage out. I totally missed that. I do want to at least run 24 vdc to reduce losses at the inverter.

@Joseph
I don't want to return to the Little House on the Prairie days, we're not Luddites. A small fridge at least and a small to medium freezer to keep my harvested chickens ( many of which can be harvested as needed), pork, beef & homemade dairy and produce-some of which we plan to sell- that doesn't can or dehydrate to our tastes will be needed. When friends and family come to visit I don't want them to even notice there's no grid involved until I tell em. What they will notice is the absence of a ton of useless gadgets.

I do agree with only cooking what you need for the day. Processed foods? BLECH!!! They will be banished from our larder. As we expand our food production we'll start making our own ketchup and mayo and BBQ sauce, the sauce IS the boss, ya know.

So can I assume the Renogy controller is a reliable unit? If so I'll get my first component on order right off.

Hi Tim,
I'm putting together a smaller system as a backup power generator to use during power outages. I have 4 x 100w renogy monocrystalline panels, a 30 amp renogy solar controller, 100 w inverter, and one 50 ah 12 v sealed la battery. It's enough to to charge phones and tablets and laptops, and power these diodes LED lights I just installed from ikea. http://www.ikea.com/us/en/catalog/products/00119424/#
I just snipped off the plug inverter and rewired with a switch to my controller.
Eventually I will buy more panels and batteries, and upgrade to a larger mppt controller, but for now I get to tinker and learn the basics for under 1000$. I've probably got about 700$ in my system right now.

I'm also in maine, just have the panels on my roof, south facing.

I was mocked by purist friends for buying a Chinese made 1.5KW (3KW peak) inverter off ebay for £90.

Well, 4 yrs later and it has been running off various vehicles, it has powered the hammer drill to dig lots of holes in rock, been out in the sun and dust, and got use at the house thru many power cuts. Still going strong and giving the rated output. The Chinese "crap" is often made right alongside the brand name stuff in the same Chinese factories. The trick is to buy from a UK seller with high ebay rating that is importing and selling Chinese goods. Then you get something that has been found and settled on by someone else who has made many buying mistakes to get to the point of finding decent quality. As you're an electrician you can always take it apart and check the wire gauge is up to the amps and the case is grounded and nicely isolated from the hot wires and nothing is stuck together with chewing gum etc.

I made my own solar panel from cells bought from US at about $0.30 per Watt. And I use old car batteries that other people have given up on, which I recondition by breaking into them and topping them up. OK they are not deep cycle but put 4 in parallel and only cycle them down to 80% and they are giving you the same charge/discharge as 1 deep cycle batt.

You can run two panels into one 12V charge controller. Just connect them in parallel. Same voltage, double the amps. The comment about losing 50% is correct, kind of, in that you need to put 50% more into a battery than it will give out, which means you are losing about 33%. But if you are using direct from the solar panel when the sun is shining then you are only losing the losses in the cabling and the inverter, maybe 15%. But a 250W panel is usually actually a 375W panel anyway. Each cell is 0.55V and they usually come out to 18V+ total if you count the cells or measure with a meter, for a 12V rated panel. This is so that after losses in the schotsky diode and cabling, the charge controller can still get the 15V+ that it wants for charging a 12V battery. So some of your 33% charging loss is already allowed for by the panel maker.

Something else that occurs is buy a cheap combined fridge freezer rather than one of each. The cheapo ones have just one compressor that runs both, giving you less precision temp control but also using less power.

For what you're doing, defo go lead acid for now, it's almost free, you can get 85Ah 12V (1KWh+) golf cart batteries for $80 brand new and stack them in parallel. Easy to maintain, not as prone to setting fire as alternatives, and can usually crank out more amps for instantaneous high loads like starting a motor. Being plug and play with your motor vehicles is another advantage in case of too many cloudy days.

Thank you gents!

Maybe we can hook up Dan. My wife has her immy visa and we'll be home for the 4th. We'll be settling near Newport, if you're in the neighborhood. With a little lead time, I'll even fire up the smoker and get some pulled pork going.

Good advise Steve. And yeah, the LA's are my first option for now. Maybe if I win the Power Ball I can upgrade to the latest gee whiz gizmos.

The MPPT I bought has (I think) a 100 V rating and I want to run 3 250 W panels in series to get me close to that (90ish VDC). I will invest in over sized cabling (w/o getting crazy) to minimize line losses. Eventually I'd like to have an array in the 2500-3000W range with a battery bank that will give me some room to use (occasionally) a tablesaw, etc on a small project, especially if I'm in float mode and have the watts to burn. I'll have a gas genny for the big jobs.

I can highly recommend the simple pump well pump with the linear bearing link drive solar motor. Works awesome. Mines a 24 volt. Its a slow pump like about 1 gallon a minute or less. You fill a large reservoir tank with a float switch and then plumb a booster pump inline to a regular pressure tank. Then viola, running pressurized water.

Eric Hammond wrote:I can highly recommend the simple pump well pump with the linear bearing link drive solar motor. Works awesome. Mines a 24 volt. Its a slow pump like about 1 gallon a minute or less. You fill a large reservoir tank with a float switch and then plumb a booster pump inline to a regular pressure tank. Then viola, running pressurized water.

You must be looking over my shoulder while I devour YT vids Eric. My main challenge is that the tank will have to be inside to prevent freezing. Maine winters are a tad rough.

I was just talking to my folks yesterday too, about incorporating a rain catchment system into the plan as well. The same set up of series plumbed 55 gal drums (or 250 g totes) would just as easily serve as a well res. A 12 or 24 VDC RV pump would handle the pressure side of the loop.

First I have to drill the well to see what the depth is. My neighbor's well is about 40' and we'll be maybe 50' down hill from him. We're coming home for the 4th so right after I wanna try my hand at dousing and see what I can learn from that.

The well driller here just recommended buying a new septic tank and burying it if I was worried about freezing, and use that as the resevoir. I however am not taking that path. I'm building a greenhouse on top of the well and having the water storage in there which is a 500 gallon BPA free tank. Plus I intend yo raise fish etc in there. I really hope all the mass of the water will help regulate the greenhouse temperature year round. I'm choosing a green house because the simple pump well pump must be pulled from the well every 5 to 10 years and have new seals put on. The sticks of PVC are quite long so I intended to just pop out one poly panel of the green house and pull the pump right through the roof.

I have actually been thinking about using a cement septic tank as a cistern. I want to know what sort of nasties are in the cement that a multi stage filter won't handle first tho.

Would you have this sort of set up in mind?
http://youtu.be/F3W03YlClmQ?list=PLU9Apt3956uWjHaD25rC31kLUBG7ifGnS

Concrete is pretty benign and unreactive as a drinking water container.

It will affect the pH of the water for a while. It will make it alkaline. For drinking water, this is more or less harmless. You could throw some vinegar in to accelerate the process. You wouldn't want to keep fish in a new cement tank due to the pH effects.

In theory, some concrete contains fly ash, which is a byproduct of coal fired power plants. It can have a meaningful amount of nasties in it, so it's worth asking the manufacturer.