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Small Cabin Forum / Off-Grid Living / Need Cost effective Solar Advice
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Rockfish Dave
Member
# Posted: 30 May 2015 10:21 - Edited by: Rockfish Dave
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Looking to install a solar power system

I'm looking for low cost reliable and powerful enough for full time use.

I've read here how members have done this for a fraction of the cost of package systems and am hoping someone can point me in the correct direction. I'm trying to get my mind wrapped around cost.

What would be helpful would be:
What to buy
Where to buy it
Installation nuances that I should keep in mind


My cabin design is 90% complete but still have room for changes.

bldginsp
Member
# Posted: 30 May 2015 11:45
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In designing a solar system it's always best to start with hard calculations of your actual usage requirements. No one can tell you what to get or how much it will cost until you know how much real capacity you need in terms of amp-hours. Make a worksheet with all your appliances and their expected use times and amperage requirements. Then design the smallest system that will handle that.

Having a backup generator available allows you to keep your solar system to a bare minimum in capacity since you can charge the batteries with it when necessary.

Take a look at the new Tesla home batteries, lithium battery packs for off grid use. Don't know if they are right for you but lithium lasts longer than lead-acid and doesn't require as careful monitoring.

Rockfish Dave
Member
# Posted: 30 May 2015 12:27 - Edited by: Rockfish Dave
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Thanks,

I probably should have been clearer in my original post:

What equipment is needed? (Inverters, panels, etc.)

What Brands/models are best values?

What retailers carry the items?



Good pointer on the spreadsheet, I'll do that next.

Clearly I have no idea of what is available or needed.

I do fully understand that I need to have an accurate estimate of peak use though.

I'm hoping someone can help me navigate the myriad of products that are out there and avoid getting poor equipment.

Rockfish Dave
Member
# Posted: 30 May 2015 13:44
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Found a series on youtube that is helpful:

https://www.youtube.com/watch?v=eR4qhbJ2g3M

https://www.youtube.com/watch?v=-PT8xBcgeZs

https://www.youtube.com/watch?annotation_id=annotation_3837970787&feature=iv&src_vid= -PT8xBcgeZs&v=JdPP4_meZ3Y

https://www.youtube.com/watch?v=-kQr85t8u_Y

groingo
Member
# Posted: 30 May 2015 14:00
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Hot tip, figure how much power you need, where you are then quadruple it and you will be pretty close.
Equipment, efficiencies, mis calculations, weather and just generally crappy equipment can make a dramatic difference between wheat you think you need and you actually need.
Best advise, work into it in stages, see how it goes then if need be, ad to it, there simply is no one size fits all or one sure fire solution...baby sterps will save a lot of aggrivation and money.

MtnDon
Member
# Posted: 30 May 2015 14:07 - Edited by: MtnDon
Reply 


As bldginsp stated, the absolute first thing you need to know is a reasonably accurate estimate of how much electricity will be used in an average 24 hour day. The amount would be expressed in watt-hours or kilowatt hours for large systems; just like your power company electric bill lists the metered use. Your definition of "minimal" may be different from mine, or bldginsp's, or anyone else's. Your TV may grow in size in the future, so a cushion is needed.


A basic equation is volts x amps = watts.
Watts x time in hours = watt hours.


What to buy and where to buy comes after the estimated consumption is a known fact (or good estimate).

For solar the "what" includes, PV panels, charge controller, inverter and batteries. The best inverters include a charger to be used with generator power. There are other parts required for installation.

So, I recommend you carefully make a list of what you want to use and how long each day each item would be used. The list needs to include the voltage and the amps, or the watts.

Some things can be run off DC voltage, others are easier or demand AC (house) power. Make two lists if necessary. Some of us use both DC and AC devices. Some of us only DC, direct off the battery and others only AC, via an inverter.

Rockfish Dave
Member
# Posted: 30 May 2015 14:50 - Edited by: Rockfish Dave
Reply 


Thanks.


I am taking the advice from the previous post and working on putting together a spreadsheet on energy use to scale a system to meet my needs.

Are there any Brands/models that are known to be better (more reliable and efficient).

What are some reputable retailers that carry the items?


creeky
Member
# Posted: 30 May 2015 15:29
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I actually went the opposite way. I built the solar system i could afford and then I plugged devices into it until I reached the available capacity.

Then i added capacity and started again.

Nothing wrong with doing it either way. Initially when I did the spreadsheet for the house I was living in I needed 4kws panels and 800 amp hrs battery at 48v (If i remember correctly).

However that would, at the time, have been a north of $30k system. Instead I built a 1kw system for 5k. Really lucked out with dropping solar panel costs.

So think of it that way as well. What can you afford. then manage your loads within that energy budget.

There is also some hesitation to promote specific brands / retailers as this becomes an issue of PR / marketing folks hijacking threads. the site has seen people with 1 or 2 posts come with a question and then they start with marketing bumpf. See the algonquin thread for an example ... tho we had some fun with that.

good luck.

Rockfish Dave
Member
# Posted: 30 May 2015 16:39
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Thanks creeky. Unfortunately the budget is crazy tight and can't afford any do-overs.

creeky
Member
# Posted: 30 May 2015 16:59
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Then I would go my route. Build the most power/storage you can. There are many posts on this site to read that will help.

Unfortunately the axiom you get what you pay for applies in solar.

For my own build look at my posts here or go to my blog. See my member info for the address. I have a few solar posts here.

MtnDon
Member
# Posted: 30 May 2015 17:17
Reply 


Quoting: Rockfish Dave
the budget is crazy tight and can't afford any do-overs.


That's why the accurate estimate is needed. Then you can tell if you can even afford it at this time.

Brand name does not matter with PV panels. IMO.

Charge controllers and inverter/chargers... IMO it is nice to choose them from the same brand. Then they can communicate with each other and enhance the experience. But that means Outback or upscale Schneider / Xantrex and nobody else and that means bigger dollars than it sounds like you have to invest.

I probably sound like a broken record, but to make an intelligent selection you have to get that step #1 figured out. Then that the the knowledge of the budget can provide a realistic answer to the question... "can I afford to build a PV system?"

Steve_S
Member
# Posted: 30 May 2015 18:57
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Rockfish, I see your in Canada but no idea where... I am at foundation pouring stage (next week) but have already purchased my Solar System Link to my system description thread. Shopping & hunting around saved me nearly 10K on cost but I am self installing and not getting an ESA inspection (still being done to code) as I am not having anything to do with Hydro... They get to stay away from my property !

You really need to figure out how much your going to use. The BIG Killers are Electric ranges / ovens, tank water heaters, electric heating of any kind. Fortunately there are many good options available to replace those nasty blighter's.

!! Water Pumps CAN be solar killers, so careful planning is a must there. Same applies to anything with a motor (think furnace blower).

240V requirements: Do you really need anything 240V ? Something else to think on.

I went with Propane for stove & on-demand water heater. The heating will be with the wood stove (Jotul 3TD) & in-floor radiant heat (Pex being put into my Frost Protected Slab Foundation) which will be heated partly by radiator beside wood stove & separate on-demand unit.

Lighting is the easiest to trim on and I have already been on all LED for my home for 3 years now. Ikea has best pricing and super prices when on sale for LED bulbs & strips. My fridge is a Danby Apartment style High Efficiency which only uses 300kWh per year, they have newer & bigger models now with same power usage.

Spend the 20/25 bucks on a Kill-A-Watt metre and check all the electrical gadgets to see what they really draw and add them all up.

Then prioritize "Need to have", "Want to have" and last but not least "Like to have".

Almost all Hydro Companies show your power usage broken down to daily averages, so that is also a good start to see how much you use now and how much you can trim off.

Just an FYI, I spent a year researching and this past winter seriously attacking my plans and fine tuning materials to suit my particular usage needs. I also have heavy tools like MIG, Table Saw etc which will only be used off Genny Power (I have a big 7/9kw unit for that side of it).

Rockfish Dave
Member
# Posted: 30 May 2015 22:20 - Edited by: Rockfish Dave
Reply 


Thanks Steve great link. Kind of what I was looking for.

groingo
Member
# Posted: 31 May 2015 01:31 - Edited by: groingo
Reply 


First get the KillaWatt power meter and see how much juice you are actually using then start checking and keep close track of the sun exposureon your property, do you have trees or vegitation that may block the sun and how much blockaage at what times of year on your property specifically and not some chart.
Can you reduce power requirements by using other methods?
My best tool that has saved me a bundle is to remove electricity from the equation wherever possible and use something else or some other way entirely....it's not something that can be packaged.....there yu go it works, you need to think outside the box or better yet re-invent the box and don't let anyone no matter how wacky the idea "it can't be done" but over all, keep it as simple and focused as possible.....there, I've spoken my piece, time for some pie.

Julie2Oregon
Member
# Posted: 1 Jun 2015 02:43
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Ditto to what groingo wrote about prioritizing. I've kind of made a brain-teaser game of how I can avoid electrical appliances, if possible, save the watts for the things that don't have alternatives, and checking wattage on just about everything. It's blown my mind how many watts small appliances use -- yikes! So, a big no to a toaster and coffeemaker. It's oven toast or "fried" bread and French press coffee for me!

I've found some really cool products, too, that do double-duty, such as a lighted medicine cabinet with motion sensor night light that runs on regular batteries and solar lamps with little built-in solar "panels" that also charge cellphones!

I'm on a limited budget, too, and I don't want to spend a lot now when the Tesla Powerwall will be available in a year or so. I want to have about 1,500 watts available daily, which should be enough for a small chest freezer, a couple of LED lights, a few hours of TV and the laptop per day, and an RV water pump. Stove and on-demand hot water will be provided by propane. I'll have a propane generator, too.

A suggestion: Monocrystalline solar panels cost a bit more but they're better producers in partly cloudy or lower light conditions, from what I've read. Better quality in construction, too.

Rockfish Dave
Member
# Posted: 11 Jun 2015 10:08 - Edited by: Rockfish Dave
Reply 


Yes, I get it, and have pretty much done all that I need to do. The only appliances that will be running 24/7 are the Refrigerator and Freezers. The game plan is to have LPG for as many appliances as possible as well as the generator.

The only things that are planned on being electric are the LED lights, ceiling fans, Ductless Heat Pump, Washing Machine (dryer will be a gas heating element), and Chest Freezer and a Chest Freezer converted to refrigerator.

Heat will be wood stove and LPG vent less radiant heater, water heater will also be an on demand LPG Bosch model.

The Generator will be used to supplement energy needs at peak times (Laundry, A/C, charging batteries, etc.).

Unfortunately no one has stepped forward with any recommendations on good/bad equipment.

What I would really like is either: what to get or what to avoid based on personal experience. It would be immensely helpful. Thanks

creeky
Member
# Posted: 11 Jun 2015 11:14
Reply 


Rockfish, if you go through the search/forums you will find the many solar builds that people have done, discussions that have taken place. This might help you. Blanket questions are hard to answer when you don't have specifics in mind. ya? That's why folks suggested you calculate either your budget (me) or your expected power usage (others).

So you mentioned, vent less heating: You will see it's recommended to use a vented propane heater.

The japanese Tagaki water heaters are the best quality. Most of us use lower cost models.

But when you ask a question that is basically (by example) "I need transportation what do you recommend?"

what are people to say? get a bike. fly a plane. a truck. we don't know what distance you are traveling? etc right.

hope you don't mind me pointing this out.

ps-steve_s 's build is probably pretty close to what you need. good luck.

Rockfish Dave
Member
# Posted: 11 Jun 2015 12:51
Reply 


In the previous post I clarified the energy requirements.

I think his system would be kind of over kill. Since the elec. requirements are minimal, as will be the heating/cooling energy required.

As good as his post is, it does not address what I am seeking. In a nut shell: "what to get or what to avoid based on personal experience".

The cabin in addition to being small is ICF with 8" of compressed boron treated cellulose insulation in the ceiling/roof space. The roof is a metal roof with 4" stand off for air flow to the ridged Styrofoam with reflective aluminum backing as the radiant barrier.

The plans are drawn, build site prepped, the builder selected, now I just need to order the energy related items.

I have been reading here for some time. That is why I posed my question the way I did. I'm sure that there are some here that have built a system and are either happy with how it turned out, or some that had bought equipment that was less than satisfactory. Sharing that information would be helpful.

The system I am targeting: 24v (or 48v?) 800W array and 3-500 Amp storage.

offgridjunkie
Member
# Posted: 11 Jun 2015 13:28 - Edited by: offgridjunkie
Reply 


Fill this out and we can calculated down to the watt. [img=null]null[/img]Let me know if you have questions. As far as equipment to look at, nothing off E-bay or Amazon. You are going to want a high quality charge controller and Inverter. Stick with Grid Tie panels in the 250-325 watt range.

_ Well it seems like I can not up load the file I wanted to. Send me a pm with your e-mail and I will send it to you.

We need to know what your total watt-hrs per day are going to be, then we can calculate it out and recommend equipment for you. What we are going for is a balanced system.

creeky
Member
# Posted: 11 Jun 2015 13:57 - Edited by: creeky
Reply 


redacted due to excessive length

Rockfish Dave
Member
# Posted: 11 Jun 2015 14:37 - Edited by: Rockfish Dave
Reply 


Creeky:

"The only appliances that will be running 24/7 are the Refrigerator and Freezers."

"The Generator will be used to supplement energy needs at peak times (Laundry, A/C, charging batteries, etc.)."

"btw. from what you've described as your expected loads. unless you live in the land of perpetual sun, Steve_s 's system is 1/3 less than what you probably need." [Creeky]

The only thing I want to use the battery/solar power for in addition to the chest freezer and chest freezer converted to refrigerator are the LED lights and ceiling fans when needed.

That seems like allot less than Steve_s's requirements. Not sure what you are talking about. I think you are assuming the cabin is in Canada? Hint: It's not

During peak charging time I can run a little more (maybe a smallish LCD flat screen and DVR) without dipping too deep into the batteries (figuring around 600w actual peak charge from solar).

Yes. I get the orientation, and have factored that in. Where I am located it is splitting the difference between optimal summer and winter angle.

Truly a minimal solar power system.

I appreciate your interest and effort, but I really am just looking to utilize the experience of others as to what equipment is best or what to avoid. Budget may be tight, but it will not help if I purchase 3 times to get equipment that works.

Rockfish Dave
Member
# Posted: 11 Jun 2015 14:53
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offgridjunkie


I can't seem to figure out the PM system on this site. Can you point me in the right direction?

offgridjunkie
Member
# Posted: 11 Jun 2015 14:59
Reply 


Click on the Member under my user name and you will find my e-mail

Rockfish Dave
Member
# Posted: 11 Jun 2015 16:38
Reply 


offgridjunkie
Got it thanks, email in bound.

Rockfish Dave
Member
# Posted: 12 Jun 2015 00:30
Reply 


So being generous like Freezer Chest and Freezer Chest converted to a refrigerator, and all the LED lights running 8 hours a day my total daily watts are 961watts a day.

That is pretty much the worst case scenario...

Like I had mentioned the high load items like Ductless Heat Pump, Washing Machine, Dryer, etc. will only be used with the generator.

So for lights, and continuous freezer and refrigerator use, I think the 800 watt system will fine.

Even at the lowest daily insolation for area and time of year the system will be used the battery system will be over kill, it will likely have a week to charge back up between use.

The cabin will be used mostly on the weekends, and a few week long stays, in those cases the generator will likely see use for charging the batteries.

offgridjunkie
Member
# Posted: 12 Jun 2015 12:55 - Edited by: offgridjunkie
Reply 


Rockfish, Are you planning to have the Freezer Chests run when you are not there? How many watts / day are those using?

rockies
Member
# Posted: 12 Jun 2015 20:28
Reply 


This magazine is very helpful.

http://www.homepower.com/

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