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Small Cabin Forum / Off-Grid Living / brief primer on solar equipment 2016
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creeky
Member
# Posted: 14 Apr 2016 10:28
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well the spring season is upon us and folks are buying solar stuff. so I thought I'd do a quick primer on solar stuff to buy.

Batteries: Buy nothing but lifepo4 lithium. You can source to 50% discharge for max life. Ie. a 5kw battery bank gives you 2.5 usable daily cycle for something like 15 years.

You can search the web, or my past posts, or my blog. But lithium will last longer and cost less and need no maintenance. It is also at least 20% more efficient charging then the heavier options. For seasonal folks. The batteries are easier to transport if required. And don't need to be charged while away. In fact, discharge to 60% and leave them for years. No worries.

Anybody recommending anything else is likely a salesman. You've been warned.

Controllers: There are some nice new controllers out there. Victron and the B series from China (epsolar, various rebrands) look really good. And prices! Wowza. Quality is up, cost is down. The morningstar remains the go to. they have new lower price mppt controllers out as well.

Mppt is a must. Panel Voltage (higher is better, but 100v min). And amperage is the key (so your panels can be whatever voltage but the amperage must be close to controller spec).

ex: 1000w solar panels needs a 60 amp controller on a 12v system (12.7x60=800 watts of panels. You're overpanelled slightly. which, with a good controller, it's what you want.)

Note: over amperage is okay. Over voltage is not. So buy a controller that is rated at least 15% over your coldest day panel voltage.

Inverters: Some new inverter/chargers from Europe. Pricey, but much better quality control. I would buy one of those. In fact. I did. I bought one of the first TBS (now in the US as MasterVolt or some'at). Three years of continual operation. No problems. Huzzah.

Look for efficiency. Should be 90% or better. Idle load is very important. Many of the new inverters are 10 watts/hr or less. Remember, older inverters will be 35 watts/hr. Do you really want to spend 875 watts a day powering your inverter? My TBS eats 200! 675 watts for free.

I also recommend, for full timers, inverter/charger combos. They were hideously expensive when I built my system. So I built ats, charger, inverter separate. It worked out. But a combined unit makes install much easier.

Now brand/warranty becomes more important. I trialed a good brand name inverter/charger. The ats dies. And that kills the whole unit. The charger worked, the inverter worked. But the ats (automatic transfer switch) blew and that meant replacing the whole shamoozle. Not recommended.

Solar panels: Poly or Mono. Doesn't really matter. But BIGGEST is best. 250 and 300w panels give you the best bang for the buck. They also need less wiring. Have better construction.

However you will likely need an mppt controller to get the most out of the panels.

Bits and bobs: Wiring etc is pretty straight forward now. Look for a reliable brand name and lowest cost. There are many good wiring diagrams on the site. You'll find one to match.

You probably need: Some sort of power monitoring if not provided by the solar controller. Fuses! Definitely. Cables that can handle the max amperage of your input/output. Combo boxes. Etc.

Good luck. And if anyone has an equipment suggestion. Have at it. If you've posted an equipment list or diagram might be nice to put a link to it here. Enjoy all.

bobrok
Member
# Posted: 14 Apr 2016 11:51
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Perfect timing for your post, creeky. Thank you.

I had saved this from a thread last year with the intention of swapping out my cheap, inefficient unit this spring. Other than a new efficient, fanless inverter right now I don't plan any changes.

Would this still be a good 'plug and play' inverter given my other equipment and batteries are old school?

URL

creeky
Member
# Posted: 14 Apr 2016 12:27
Reply 


that inverter is exactly what I'm talking about.

and it's been around for years. ha!

also brings up a good point about "how big?" bigger inverter means more idle power wasted.

and how to build your system. i think most of us have "upgraded" a component or two on our way.

(some more urgently than others. I added a charger my first year discovering how cloudy nov/dec in my area is. changed my inverter when the first one, uh, died. that was urgent! Added an ats when the inverter mfct put out a warning about the effect of chargers on inverter electronics...)

live long grow and prosper I guess

NorthRick
Member
# Posted: 14 Apr 2016 14:27
Reply 


Quoting: creeky
Batteries: Buy nothing but lifepo4 lithium. You can source to 50% discharge for max life. Ie. a 5kw battery bank gives you 2.5 usable daily cycle for something like 15 years. You can search the web, or my past posts, or my blog. But lithium will last longer and cost less and need no maintenance. It is also at least 20% more efficient charging then the heavier options. For seasonal folks. The batteries are easier to transport if required. And don't need to be charged while away. In fact, discharge to 60% and leave them for years. No worries.



It's not that black and white. If you charge lifepo4 when they are below freezing, they can be damaged. We have a weekend cabin that sits unheated when we are gone. We rely on the solar panel to charge the battery bank to full during the week when we are not there and quite often it is below freezing. So, it is still flooded lead acid for us.

Also, you need to make sure your charge controller can be adjusted to properly charge lithium. Many can't do this and you will damage your expensive batteries.

KelVarnsen
Member
# Posted: 14 Apr 2016 15:32
Reply 


Maybe something like this might be available in the near future: link.

The all-climate battery uses a 50-Ám thick nickel foil with one end attached to the negative terminal and the other extending outside the cell to create a third terminal. A temperature sensor attached to a switch causes electrons to flow through the nickel foil to complete the circuit. This rapidly heats up the nickel foil through resistance heating and warms the inside of the battery. Once the battery is at 32F, the switch turns off and the electric current flows in the normal manner.

Rickkrus
Member
# Posted: 14 Apr 2016 18:23
Reply 


Can you recommend a specific battery? Looking for a 1500 watt solar system

MtnDon
Member
# Posted: 14 Apr 2016 18:53
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Quoting: NorthRick
It's not that black and white.


Agreed. Especially when there is a quantum difference in price. I am well aware of the arguments for and against LFP. Lots of good; the big drawback to many folks looking at small cabins is the out of pocket "right now" price.

The freezing cold is and is not an issue, from my point of view. In our cabin we will need to relocate the batteries to an inside location, a secondary one time issue.

On the plus side if the batteries are at least half to 3/4 charged I would have no qualms about leaving them over a winter absence. Leave the PV charge system turned off. LFP don't care about how cold it gets if they are just sitting there doing nothing. It would be a different matter if the system had to be operative to power security or other systems. When you (or I) go back, warm the cabin and batteries to above freezing before turning the PV system back on. If left at 50 to 80% charge the batteries can be used to power lights, etc and that will help warm them too.

However I think back to when we were building on our mtn property... spending another $2000 on batteries at that time would have delayed other things.

rockies
Member
# Posted: 14 Apr 2016 21:21
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Excellent information. I toss a gauntlet down to you though.

While all the individual parts of a solar panel system are discussed few people know how much power their system really needs or how to house their system when they come to install it. Can it all go into a small space inside the cabin or is a stand alone small building better suited for it? I was wondering if you could do a sample diagram for a typical small cabin system (like mine?)

I plan on using a Sunfrost RF16 fridge and a Unique 120 liters Portable Solar Freezer . Cooking will be on an induction cooktop. There is no water heating, space heating, washing machine, dryer or dishwasher. There will be led lights, TV, computer and radio and there might be a Nuwave oven. The only other things might be typical small kitchen appliance stuff.

One thing not usually considered is hoe to power a well pump. I heard they can be run off of a separate solar panel that doesn't really need to be connected to the battery bank. Is that right?

If you decide to do this perhaps you can recommend changes to appliances or things most people forget to include when designing their system? You seem to have far more experience with these systems than most other people. Thanks

rmak
Member
# Posted: 15 Apr 2016 05:49 - Edited by: rmak
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If it will help anyone, here's the story about my solar adventure. The system is still working fine several years later.

http://www.small-cabin.com/forum/3_4817_0.html#msg70949

I used Trail Solar in Central Ohio
http://www.holmescountyshopper.com/local%20news/2011/11/10/trail-battery-and-solar-kn own-for-made-in-america-high-quality-products

creeky
Member
# Posted: 15 Apr 2016 09:24
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excellent posts all. thanks rmak. yours is a good small system to look at. nice schematic. And very tidy install. wish mine looked as good.

nice spot KelVarnsen. I plan to use a seed starter blanket attached to a temp switch. Should be the ticket. May get all fancy with arduino tracking, but don't count on it. I will also be wrapping in 6-8" of polyiso. The batteries may not generate the heat that lead acid does but at 93-95% efficient there is some heat generated for sure.

(btw. I have my lead acid battery pack heavily insulated with xps/polyiso in an insulated building. I keep them around 10C/50F so that there's power in them. Lead acid drops power alarmingly with temp. So nothing new here. They self heated all winter. It was mild. Lowest temp was -1/30F. But mostly stayed around 10C)

Anyone who can't keep their batteries warm is going to have even more trouble with lead acid. Filling water. Remembering to equalize. Lead acid is a lot of constant drudgery. Along with a lot of extra wiring and storage cost.

Rickkrus. I don't know what use you're using. But a 5kw from Balqon could do the trick. Give you 3 kw daily for the next 10 to 15 years. That's lights. Fridge. Induction cooker. A/C. Dishwasher. All with good mgt of course.

Rockies: one advantage of lithium is no off gassing. no explosive fears. Put your batteries inside the house in a small closet. You're done. This is a key advantage. No separate facility required. Especially when you get to larger systems, lead acid gets heavy (I'm at 720 lbs). Takes up a lot of $ space (even built at 30/sq foot). And needs to be vented. Kept warm. Etc etc.

On the good solar mgt side:
For your needs, why have no washer etc? If you have solar you have the power. You simply adjust your usage. Wash laundry, heck I run a dishwasher with electric heated water, in the afternoon. Once the batteries are charged, even easier with lithium, you're good to go.

I would lose the expensive "solar" fridges. They're just expensive. A basic "estar" fridge, 15-18 cu ft, from a big box is less than 800 bucks. Anything that uses 300-350 kw/annual you can run off of a 1kw solar set up. I've done it for 3 years. Now you have thousands to put into a better solar system. In fact you probably just paid for the battery upgrade to lithium.

And it goes double for propane. A propane fridge pays for the battery upgrade vs an electric one. My little 10 cu ft cost 400 bucks. that's 1200 in savings off a propane fridge in my area at that time. now it's 3 years old. Add in another 1000 in propane savings. There. 2200 towards the lithium pack.

With 1.5kw solar Rickkus is good to go on an electric fridge. And a small a/c unit for those miserable hot days. And internet. and tv. and ...

I do like my propane hot water and stove though. The stove more for the ease of cooking. Nothing beats a gas stove. I like my induction hot plate for slow cooking. But it's not that useful for stirfry or ... tho it does boil water fast. I have an acquaintance who uses induction for cooking. I can see the appeal. An induction hob doesn't take up much room. anyway.

and propane hot water. with on demand you don't use that much gas. I fill a 40 lber about once a year. I do heat a lot of water on the wood stove in the winter though. And will be installing a solar hot water heater for the summer showers this year. probably adding an outdoor shower as well.

but my point in all this is that the tech has changed. lithium is only about 50% more. And the performance benefits make it worth the cost. The fact that it's cheaper in the long run is just a bonus. Trust me. Lead acid blows monkey chunks. And only gets harder to use as the systems get bigger. I see guys pricing lithium vs la and totally forgetting all the add on costs. The extra storage space. The vents. The extra heat loss. The extra building built (as in my case). The wiring. The lugs. The need to keep the battery cool. Go to the RV sites. See how many people burn through the la battery packs every 1.5 years from over heating / excessive dod.

The balqon, by example, (I'm not associated at all in any way), comes complete with fuse and everything. That's a savings right there. And takes up 1/3 the space of a lead acid pack.

And the facts remain. It is far cheaper and less bother. But most importantly, performs better. Better charge/discharge efficiency (there's a reason my la batteries can keep themselves at 10C in week after week of -10C temps with nothing but some insulation). Longer life.

Really key though, is you can happily discharge even at 50% dod not worrying your killing your batteries. Run la at 50% dod and they're dead in 2 years. Go to 80% and they're dead even faster.

Lithium 100 amp cells are available for less than 100 bucks right now. you can build a 12v system for 400. Top balance. Keep an eye on them of course. Forget the bms. That's an easy 600w daily for the next 15 years. need more power. parallel in another pack. doesn't matter when.

VS lead. to use 600w a day you need 250 amp hours. And then you can water. Throw away every 3-5 years. Can't expand. Need extra solar to charge. Have to worry in the a.m. when the wife wants to use the electric hob, "just to boil some water," whether your 5 year life just went to 1.5. Etc etc. Can't add another pack as the old packs kills the new one. etc.

Larger lithium systems for small houses/cottages should use a BMS. They've really dropped in price. 200 should do it. Unless you get carried away and then 370 with "battery fuel gauge." Btw, a fuel gauge for lead acid also costs 170 bucks.

Anyway, getting a bit long winded. The point remains. Some good quality new stuff out there for solar. Have at 'er, yar.

silverwaterlady
Member
# Posted: 15 Apr 2016 11:05
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I don't have a suggestion since we haven't invested in solar but I do have a question.
We would like to run a small pump from our water tank to our shower. We don't have enough water pressure to our on demand shower to keep the pilot light lit.
I like to take long showers so can anyone tell me what I need to run this pump? I would like to use a lithium battery and plan on taking it home with me.

Julie2Oregon
Member
# Posted: 15 Apr 2016 15:20
Reply 


Creeky,
Do you recommend 12V or 24V for just average household use? I've been planning on 12V but have found some package deals with 24V, and the Balqon 6 kW 24V lithium battery is just $800 more than the 5 kW 12V so it's not a huge deal-breaker.

Also, if your inverter charger is 24V, could you use that with a 12V battery or does the battery also have to be 24V?

Thanks! (The reason I'm asking is that if I do go with a modular or other construction company for the build and roll this all up into a construction loan, then it's possible to include the solar in that and have them install it for me, rather than my arranging a separate contractor. That's why I'm looking at solar packages and then buying the Balqon battery for the package.)

Bret
Member
# Posted: 15 Apr 2016 18:07
Reply 


J2O:
Those are all good questions. I'm back and forth between 12v and 24v. So this is a great conversation for me. Thanks for starting it Creeky.

creeky
Member
# Posted: 15 Apr 2016 19:09
Reply 


I went 12v as I had a travel trailer. Thought it would be better to have 12v for the trailer. I was wrong. I only ever used the 115 to the trailer. Sheesh.

24v is the way I'd go Julie2/Bret. Especially if you get an extra kw of power. Keeps the wiring smaller. Handles higher amps more gracefully. But once your 24v you're pretty much stuck there. Well. you can use a buck converter. But why?

>You could even look at 48v.

So caveats:
12v appliances are easy to find. 24, still okay. But when you start looking at 48v and above, even inverters etc start to become scarcer. And scarcity breeds cost. Sadly.

Note:
What I found though. I'm all 115v ac now. Even my old 12v shurflo sits idle. This summer I will hook it up to use as a garden pump. Standard ac appliances are cheaper. More design options. More convenient to buy. To me it doesn't make sense to think about DC.

(Maybe in the future? It does seem odd that we transform our ac into dc for so many of our modern conveniences. From tvs, to phones, to stereos, to a/c. ah well.)

Silverwaterlady. Any good 12v pump will give you enough pressure. The Shurflo revolution is popular around here. You'll want a small solar panel system to keep the battery topped up.

uh oh. boss is calling. supper time.

rockies
Member
# Posted: 15 Apr 2016 19:31
Reply 


Thanks for your reply. I suppose the reason I was considering one of those hand crank washing machine devices instead of an electric washing machine is because when you start to plan going off grid you're "kind of expected not to want or need all those big city gadgets". For the last 30 years "getting back to the land" implied that you'd be doing everything manually with maybe a few modern conveniences like a chain saw or a 12v string of lights.

Now, of course, you can have pretty much anything you want but you're still made to feel that you should cut back, install solar hot water heating, forget the dishwasher, etc. That was the reason why I was also considering the Sunfrost fridge. You almost feel guilty if you're not buying a specially designed "off grid" appliance.

Another reason for not planning on all the modern conveniences is that people assume that buying the solar panel system to rrun it all will cost them tens of thousands of dollars. I remember reading homesteading articles in Mother Earth News in the 1980's and thinking "Do I want to be tending an extremely complicated system everyday just to have basic power"?

Since you've suggested buying a common estar fridge I will look at those. I do plan on putting the whole power system (along with the wood fired indoor boiler and hot water heating) inside a small out-building about 20-30 feet away from the cabin. I'd rather have the noise and mess out of sight and use the cabin space for living space rather than storage. I could also put the laundry out there too since I'm a guy and only do 1-2 loads a week. Why take up space in the cabin with a washing machine that sits idle most of the time?

What about the well pump though? I've read that some motors take a tremendous amount of power to start up. Should the well pump be on a separate panel or wired into the main system?

silverwaterlady
Member
# Posted: 15 Apr 2016 19:52
Reply 


TY,Creeky.

creeky
Member
# Posted: 16 Apr 2016 11:17
Reply 


Quoting: rockies
I was considering one of those hand crank


This is the question. Just like in small/tiny house. What suits you. For me the hair shirt off grid experience isn't what I wanted. smile. But you know. Things really change with full time. It's fun to go camping. But aren't you always real happy to fall into that comfy bed after a hot shower when you get home ...

Heck, I run a zigbee network along with wifi. I can control lights/internet from the comfort of my bed. To me that's off grid.

Your solar system, for full time off grid, without the hair shirt, comes in at 5-7k. that's 2016 top reliability (self-installed of course). And it's why I started this post. Never hurts to repeat the truth.

With today's equipment. Its also a no fiddle faddle system. The bulk of which is good for 25 years. You'll probably have some replacements required around year 10. Hopefully later.

When you've seen many people spend more on "toys" to run around country property on. Or calculated the depreciation the minute you drive a new car off the lot. It's pretty affordable.

I'm not the best person to ask about well pumps. So many variables. My dream system would be a stand alone solar powered pump filling a cistern. From which I use basic shurflo pumps to run the appliances.

I inherited a deep well with 230v pump. I use my genny on it to fill my cisterns. And then use 115v pumps (2) from there. I also collect rain water. Am planning a pretty major upgrade there this year also. I like the softness of rain water when I do laundry or shower.

am I digressing?

Julie2Oregon
Member
# Posted: 16 Apr 2016 16:21
Reply 


creeky
Thank you!!!! 24V it is!!!!

Now that I'm looking at buying an existing cabin that already has electric, I have the luxury of doing grid-tie. Now, that doesn't mean that I'm going to be altering my plans and consuming electric with abandon. What it DOES mean is that I will be an existing electric company customer and, as such, will qualify for the Energy Trust to pay a nice chunk of my solar conversion and installation! And there's that net-metering benefit in which they pay me.

So, I can afford to go bigger and better with my system. Def the bigger Balqon battery. What size of an inverter would you suggest? Because now I can get a small clothes dryer to go with my portable washer! Very big grin.

rockies
Member
# Posted: 16 Apr 2016 18:04
Reply 


What is your blog, creeky?

creeky
Member
# Posted: 16 Apr 2016 21:15
Reply 


oh. my blog.

Julie2Oregon
Member
# Posted: 16 Apr 2016 22:16
Reply 


There's the Creekster! Love the hat! Creeky, you're a Renaissance Man! Builder, inventor, artist -- seriously impressive.

creeky
Member
# Posted: 17 Apr 2016 07:27
Reply 


Julie2.

rmak
Member
# Posted: 17 Apr 2016 11:39
Reply 


Thanks for the link to your blog! I'm an easel painter, mostly oils. I was glad to see your work. Good color/value sense. And we both know that's more than half the ball game.

creeky
Member
# Posted: 18 Apr 2016 09:49
Reply 


That's very kind of you to say rmak.

I worked with a very talented artist in an art gallery's framing shop. Earning the money to go back to school. His knowledge and experience were a real gift. Made a lifetime friend.

There are three things I love in art. Colour. Love colour theory. Hand. I'm afraid I'm rather picky about the "hand." Some people get it as a gift. Others have to work for it a bit harder. And structure. Really structure is something we have to learn I suppose.

But once you look at those three elements you can have, at least imo, an aesthetic understanding of all art.

Sure you could add theory. But I'm not a huge fan of theory only art. Well. Unless it relies on colour theory. And being of that theoretical musings type. I don't mind a good theoretical bash about.

Kind of like solar power. Having a knowledge of the w=aXv is the technical stuff; which becomes structure. The hand is the assembly. To be able to tighten the bolts with enough force they don't come off but not so much you strip the thread. The colour, is what you create it for. The understanding of how to get the most from what you've created.

getting a bit out there now

rmak
Member
# Posted: 18 Apr 2016 17:15
Reply 


Quoting: creeky
getting a bit out there now

Naw, man, you are just getting back on topic. Sorry for going off on one of my tangents.

rockies
Member
# Posted: 18 Apr 2016 20:36
Reply 


I found the 2016 "Best of the Best" appliances from Energy Star Canada.

https://www.energystar.gov/most-efficient/me-certified-refrigerators

The Frigidaire seems to be a good one. 18.1 cubic feet and 363 Kwh/yr

https://www.energystar.gov/most-efficient/me-certified-refrigerators/details/2219151

Also washing machines.

https://www.energystar.gov/most-efficient/me-certified-clothes-washers/

The Samsung seems to be the best for energy usage.

https://www.energystar.gov/most-efficient/me-certified-clothes-washers/details/223330 2

There are also some Kenmore ranges listed on the site that use about 299 kwh/yr .

rockies
Member
# Posted: 18 Apr 2016 21:20
Reply 


Links to freezers.

http://oee.nrcan.gc.ca/pml-lmp/index.cfm?action=app.search-recherche&appliance=FREEZE RS

This seems to be the most efficient freezer above 5 cu ft listed on the energy star site. The "Igloo" model seems to be out of stock.

http://oee.nrcan.gc.ca/pml-lmp/index.cfm?action=app.formHandler&operation=details-det ails&ref=10012785&appliance=FREEZERS&nr=1

This is 8.12 cu ft and uses 189 kwh/yr

rockies
Member
# Posted: 18 Apr 2016 21:36
Reply 


For ranges it gets a bit more complicated. They say that induction is the best method of cooking for the stovetop because it only heats the pot and not the surrounding surfaces or air. For the oven I've read that you should get a self-cleaning oven because there is a lot more insulation built into the body of the range (just don't use the self-cleaning feature).

The most efficient induction/self cleaning range I found from a well known manufacturer was this one:

http://oee.nrcan.gc.ca/pml-lmp/index.cfm?action=app.formHandler&operation=details-det ails&ref=14863286&appliance=RANGES_E&nr=1

It takes 346 kwh/yr to run. There are some regular "coil" top ranges that use maybe 20-30 kwh/hr less but to get induction I think the extra energy needed is worth it. A bit pricey at $1800 but not when compared to similar stoves at $5600.

creeky
Member
# Posted: 19 Apr 2016 09:17 - Edited by: creeky
Reply 


Quoting: rmak
tangents


I love tangents. why I was born to use oblique angles.
maybe we should start an off grid art thread.

Quoting: rockies
The Frigidaire seems to be a good one


That is a nice fridge. 18 cu ft. The U.S. has new electricity measurement rules that are tougher than the non-updated Canadian ones. In Canada that fridge uses 322 kw/yr. That's compared to my 10 cu ft at 311.

LoonWhisperer
Member
# Posted: 19 Apr 2016 15:22
Reply 


Great thread creeky! We will be setting up our baby 80 watt system in the coming weeks so everyone's input here is very helpful.

Question for the experts .... I will be running wires from the battery (outside) into the cabin and part of the plan is to setup a couple 12v plugs and voltage meter from a Blue Sea fuse block. Can I also run wires from the fuse block into the solar controller or should those wires go directly from the battery to the controller?

Thanks!

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