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OraLabora
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# Posted: 5 May 2019 08:29pm
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First, I am completely ignorant. I have been researching as much as possible in order to educate myself, (a bit overwhelming). We are planning a 320sqft off-grid cabin, -full time use. We plan to use minimum electric until we get our finances mapped out. I'm looking to power the following:
A few LED lights
2 laptops and a smart phone
A compost toilet (or homemade version with electric vent fan.)
A tiny refrigerator / converted deep freezer
Occasional box fan
Occasional charging of Lithium batteries for power tools: screw-gun, leaf-blower, etc.
I'm looking at a small generator and battery-bank to begin with since it is reliable, rain or shine. I'm trying to keep a 2k (or less) budget.
What all do you think I will need? I'm told golf-cart batteries are best for beginners...
Thank you and God Bless.
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Brettny
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# Posted: 6 May 2019 08:41am
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Loose the electric fridge and your $2k budget is more than adequate.
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SCSJeff
Member
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# Posted: 6 May 2019 09:09am
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I have (2) golf-cart batteries w/ 600W ProSine Inverter that runs all lights in house, occasional fan use, and RV water pump no problems. I charge with (1) 100W panel and (1) 250W panel. However, I run a small 2000 Watt Champion Inverter to watch TV/DVD and converted chest freezer. (However, I think I could get the freezer conversion to run off the solar without issue too, (at least during the day)) I can get by with an hour or two of TV only at night on the solar too.
Note: This is not full time use. The longest we've stayed is 4 days.
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offgrididaho
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# Posted: 6 May 2019 11:32am
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Lots of good threads on here that will steer you the right direction.
One thing of note that I just recently realized, a lot of the newer 20v cordless tool chargers are "fast chargers" and will actually draw a lot of power over a short period of time. Not necessarily a huge issue compared to your battery bank size, but worth noting when sizing an inverter.
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OraLabora
Member
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# Posted: 6 May 2019 02:49pm
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I've been reviewing the threads; Unfortunately I haven't figured out how inverters are sized, how to determine what generator would be adequate without being overkill, how many batteries would be needed, or how I would even go about plugging an appliance into the system. I've done hours of researching, but things just haven't clicked with me. The acronyms alone are enough to put me in a head-spin. I may be a determined woman, but I am certainly not a technically minded one. Give me something hands on and I'll do just fine, but start spewing numbers/loads/currents/Ah's + voltage and I'm lost. Tips anyone?
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NorthRick
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# Posted: 6 May 2019 07:40pm - Edited by: NorthRick
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You need to start by determining your loads. This will involve watts, hours, and yes, watthours. It's not that bad though.
Start with the list of things that will need power. Find out what wattage each of these things use. That will be on the label of the appliance or you can look up on line and find standard values for a lot of things. Even better, get a kill-a-watt meter and plug stuff into it and directly read what it consumes.
Once you have your list of stuff and their wattage, decide how long you will have each item on each day. Once you've done that, you simply multiply the watts a device consumes by the hours it is on and you have the watthours needed to power that device for a day. Add up all your watthours and that will give you your total daily load. You need to know this before you decide on anything else.
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offgrididaho
Member
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# Posted: 6 May 2019 11:42pm
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Basically what NorthRick said is place to start. Once you know what you're going to draw, approximately, you can start to figure out how to provide it. Even once you figure out your draws there will be losses from voltage conversions etc but worry about that later, first just figure out how many X watt light bulbs per day, how many phones charged for how many hours etc and come up with a total of watt hours per day.
To make your life easy go with what you have to have, don't try to build a system that will allow you to mine bitcoins all day or run air conditioning or do anything ridiculous, keep it simple... charge a few devices, run a few light bulbs.
If the conversion between AC and DC sounds confusing, don't let it be. Just start by adding up total watts a device uses by how many hours it's running and that's the watt hours per day for that device. Watts are just amps * volts, so a device that draws 10 amps at 12 volts (car battery) for one hour draws 120 watt hours. A device that draws 1 amp at 120 volt (household current) for one hour draws, yep, 120 watt hours.
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Brettny
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# Posted: 7 May 2019 07:06am
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Ora. Use a generator calculator to help add up your loads. If you want to find loads of items that switch on and off get your self a KillAWatt meter. Home depot has them for $20. It can track watts used for hours/days/weeks.
There are online calculators for nearly everything today. Solar system sizes, inverter and battery bank WH size all have them. You should really start with battery bank size first, then size your pannels.
Wholesalesolar.com has a bunch of online calculators but you can also just google what ever calculator your looking for.
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offgrididaho
Member
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# Posted: 7 May 2019 08:49am
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Quoting: Brettny Wholesalesolar.com has a bunch of online calculators but you can also just google what ever calculator your looking for.
They have some good PDF's you can download (I think you have to give up your email address to do it) that will give you some good overviews of how these systems work too.
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creeky
Member
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# Posted: 7 May 2019 04:47pm
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Have a look at Wilbour's system. Looks exactly what you need. It was under 1500 cad $
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OraLabora
Member
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# Posted: 7 May 2019 06:33pm
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Thank you for the references everyone; the calculators are extremely helpful! I am looking at panels a bit more seriously now that I read a genny will run about $2.50 to $5.00 per kilowatt hour. Yikes.
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OraLabora
Member
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# Posted: 8 May 2019 07:01am
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creeky
Is this the system you were talking about? https://www.youtube.com/watch?v=VwcbmfPwN7k&feature=youtu.be
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Brettny
Member
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# Posted: 8 May 2019 08:53am
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Quoting: OraLabora Thank you for the references everyone; the calculators are extremely helpful! I am looking at panels a bit more seriously now that I read a genny will run about $2.50 to $5.00 per kilowatt hour. Yikes
Where did you read that? A solar website?
Generator burn rate is very very generator specific and the price of gas changes alot. They sell open frame inverter generators now that are very fuel efficient and some what cheap.
https://www.homedepot.com/p/Westinghouse-iGen-4-200-3-500-Watt-Gasoline-Powered-Hybri d-Open-Frame-Portable-Inverter-Generator-with-RV-Ready-TT-30R-Outlet-iGen4200/3065459 65
18hr run time (prob 25* load) on 2.6gal of gas.
If i was to need to buy a new generator this is what i would get. I lucked out and bought a hardly used briggs 3500w for $50 that does 240v. Its goig to be a gas hog though.
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OraLabora
Member
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# Posted: 8 May 2019 09:41am
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http://solarhomestead.com/charging-batteries-with-a-generator/
"Making your own electricity with a gas, propane or diesel generator can cost anywhere from $2.50 t0 $5.00 per kilowatt hour compared to the $.05 to $.60 per kilowatt hour most utilities charge."
I've heard the Honda EU2200i is a really good inverted generator, but I like the price on your Westinghouse a lot better.
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OraLabora
Member
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# Posted: 8 May 2019 09:44am
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In Wilbour's YouTube solar setup he uses a 1kw Chevy Battery. Is that the way to go? If not, what's a Trojan golf-cart Battery equivalent?
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qbodsyt
Member
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# Posted: 8 May 2019 10:41am - Edited by: qbodsyt
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I would encourage you to do a lot more reading on solar and batteries before even considering a DIY solution. Creeky on here sells ready made setups but of course that's going to be pricier. A lot of lithium enthusiasts here and that's cool but lithium can be dangerous if you don't know what you're doing and you don't have proper BMS setup. If you don't know what BMS is, you're not ready for lithium or probably for DIY... electrical work of any kind is very dangerous if you don't understand the fundamentals. This site isn't particularly a solar panel education site, there are some out there with a lot more easily accessible information on the subject, I encourage you to read read read before spending any of your hard earned cash. I've been studying solar/battery tech for three years and I'm still not always sure of what I'm talking about....just some friendly advice from someone in a similar situation to you 
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OraLabora
Member
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# Posted: 8 May 2019 04:52pm - Edited by: OraLabora
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I'm not planning on lithium at this point; I've read that beginners tend to fry their batteries and I don't want to cry over such a major investment.
I've actually looked into plug and play systems, but they are pricey and right now every $ counts. My brother is an electrician, (I would take these issues to him but he works overtime and goes to school...) Nevertheless, if I have the basics along with the ready-to-go parts, he could probably walk me through it a bit.
Unfortunately, he just doesn't have time for ignorant questions. 
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OraLabora
Member
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# Posted: 8 May 2019 05:39pm
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Wow, I just realized the Chevy batteries are lithium and that used ones are not badly priced...
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ICC
Member
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# Posted: 8 May 2019 05:52pm
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Quoting: OraLabora I've read that beginners tend to fry their batteries and I don't want to cry over such a major investment.
More true with lead acid batteries, IMO. I have seen many newbies forget they have to keep the fluid level up. You can't go a year w/o checking/adding distilled water. Lithium has no water.
Lead acid react poorly when discharged to low levels all the time. Some newbies disregard that. They pay the price. Lithium has a wide range of acceptable discharge levels.
Lead acid don't react well when left in a partially discharged state for several days at a stretch. That combined with regularly discharging too deeply (mentioned above) is a recipe for early failure. Lithium have a wide range of charge levels they can sit at for months and not be damaged. Lithium actually do quite well, better even, when not charged to top levels.
The key is to buy quality hardware; charge controllers and inverter/chargers. Lithium based cells and batteries reduce the impact of human forgetfulness.
Sure quality is not cheap. However, my first quality charge controller was built 20 years ago. It is still in use with the people who bought it and the old inverter/charger from me.
However, if you need to shave the initial costs down, go with lead if you can get by with golf cart batteries. GC-2's are cheap enough at places like Costco and Sam's Club. Buy quality hardware that can be used with lithium down the road. In which case you should have hardware that is meant for a 24 volt battery system; charge controllers (good ones) can operate with assorted battery bank voltages, but inverters are designed for specific input voltages.
If you have trouble understanding how electrical things work, money spent on a good adviser saves money in the long run. Buy once, once make mistakes. Not everyone is an expert on everything. There are advisers, designers, for off grid who don't actually sell products.
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OraLabora
Member
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# Posted: 9 May 2019 07:15am
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ICC
Good read; I have a list of parts that Wilbour used per Creeky's advice:
VE.Direct Bluetooth Smart dongle $50
Victron Energy Inverter, Phoenix 500W 24v $166
Victron Energy Marine MPPT 100/15 Solar Charge Controller $107
310w Mono Panel $219
My main decision now is batteries; if I find a good lithium on ebay, that sounds like the way to go. I will also look into an off-grid "adviser" just to sure things up. 
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offgrididaho
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# Posted: 9 May 2019 11:15am
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Quoting: ICC If you have trouble understanding how electrical things work, money spent on a good adviser saves money in the long run. Buy once, once make mistakes. Not everyone is an expert on everything. There are advisers, designers, for off grid who don't actually sell products.
This is VERY VERY sound advice. I ended up doing this at the end of my design process and it was very helpful. I didn't want someone to design the system for me as I wanted to understand it, but having a pro check it out was very helpful, especially on some of the issues that are confusing to most of us like grounding.
So is drawing out a schematic (either with a computer or by hand, doesn't matter). I drew out a complete schematic of the whole system (OK, actually drew 4 completely different schematics with various iterations of each) start to finish labeling everything down to wire sizes and ring connector sizes. This will be really really helpful in catching the little nitty gritty things that escape when we all just think about the big picture.
THEN take that schematic to your friendly local solar guy (might even be able to find someone to do it after hours for a modest cash fee... here we have companies that do giant McMansion grid tie solar installs who wouldn't have been bothered with designing or building my little system but are happy to look at schematics for beers and a little cash) and have them go over it with you and look for problems.
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Steve_S
Member
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# Posted: 9 May 2019 05:30pm
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I word of caution on the Generators your see out there... The HONDA is a Genuine Real HONDA ! When you look at "Westinghouse", "Hyundai", "Energizer" these ARE NOT THOSE "BRAND NAMES". For example, the Energizer "Brand" is made in China by Quinqan ? and sold through a VAR used under license by Midland Power Inc. The "Label" does not means it is the company you "think" it is...
Regarding designing... I would suggest looking at the Midnite Solar Inc REF: http://www.midnitesolar.com/ as they have excellent human readable documentation for their controllers, wiring them up and all the various options. I myself have a Classic 200 and I more or less followed their documentation & suggestions with a few extras for my 0wn sanity. (Rule of 3 applied, triple redundancy etc).
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offgrididaho
Member
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# Posted: 9 May 2019 06:14pm
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Also as far as generators, since I just went down this very path, check out the EG2800i as well. 2500 watts continuous instead of 1800 for the EU2200i, a little bit louder but not a big deal in a cabin sort of situation (I have an EU1000i that I love for my pop top camper van because we're very noise sensitive in that, often in campgrounds where we're trying to be good neighbors, but in the cabin setting the EG2800 was a much better fit for us, more power, bigger gas tank, same price).
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beachman
Member
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# Posted: 10 May 2019 10:20am
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Back Woods Solar (backwoodssolar.com) has a great site and a downloadable solar products and installation guide - also comes in hard cover for off-grid camp reading. All free. They sell products but give good advice.
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