Want book recommendation on off grid design

odys99

Thanks for the great forum. Lots of great info. All the info a beginner needs to understand PV design is here on the forum, I'm sure, but I'd rather not read 300 posts, if you know what I mean.

Is there a book, or single webinar, or whatever, that covers well for beginners the basics of PV design principles in specific detail, such as- factors in determining usage requirements, factors in determining battery size, type, number, factors in choosing charge controllers and inverters, factors in choosing panels, wire size calculations, etc. What I want is to understand how all components operate electrically, and the different designs/configurations available, their advantages and disadvantages, so I can decide for myself which design configuration works best for me.

When should a system be designed with higher DC voltage output from the panels, with corresponding charge controller, and when should a lower DC output design be implemented? When should the user stick with a DC system in the house/cabin, when should they invert to AC? What I want is a book that explains the electrical principles involved so that a person can decide these things for themselves, rather than a book that tells you how to install the author's system without explaining how it works, or all the possibilities.

Reviewing books available on Azmazon, I did not find one that focuses on clarifying the different specific electrical principles involved with each of the separate components.

Is there such an instructional manual out there, or do I have to read 300 posts and 6 books, all tangentially related, before I finally discover all the factors relevant to basic small scale off grid PV design?

vtmaps

Re: Want book recommendation on off grid design

odys99 wrote: »

Is there such an instructional manual out there, or do I have to read 300 posts and 6 books, all tangentially related, before I finally discover all the factors relevant to basic small scale off grid PV design?

Welcome to the forum,

Actually you need to read more than 300 posts and 6 books. See if you can find a local library that carries Home Power magazine. They have a number of articles on the subject.

covers well for beginners the basics of PV design principles in specific detail, such as- factors in determining usage requirements, factors in determining battery size, type, number, factors in choosing charge controllers and inverters, factors in choosing panels, wire size calculations, etc.

The first step in any system design is to know "What do I want this system to do?".

That means you must know your loads. Your peak loads, your average load, the time of day of the loads, and the duration of the peak loads. Once you do that, you can intelligently design on paper a system that will power your loads. Many folks are surprised and disappointed to learn that most of their system is not usable when they need to upgrade their system... it pays to get it right the first time.

After you figure out your loads, come back to the forum and you will get most of your questions answered.

--vtMaps

zoneblue

Re: Want book recommendation on off grid design

If you are building more than a small system and want to do it yourself, then yes, you are in for a wild ride. The learning curve is all part of the fun. This does however assume that you have some electrical common sense, otherwise get some help. Its easy to underestimate the consequences of bad decisions in off grid electrical systems. But, agree with vt, 3000 posts might be closer to it.

BB.

Re: Want book recommendation on off grid design

It is not that bad--It is worse :roll:.

I suggest that you "walk" your way through designing "your system". A Kill-a-Watt meter (for AC power) and an AC/DC Current Clamp DMM are a couple of basic tools to start with.

For a cost efficient system--You really need to know/understand your loads.

Next, we will go through some "cook book" math and start a paper system design (to see if it meets your needs)....

Once you have nailed down the basic system requirements--Then you can start looking at hardware (don't buy and solar parts before the first couple steps).

You will be "much happier".

Anyway, here are some books on the subject:

Regarding Solar Books:

What's a Good Beginners Book?

From the above thread:

FL SUN wrote: »

This is a link to a PV textbook I find very informative. It was a requirement for the FL contractor's exam I took last month. It even has a very good interactive CD with a bunch of informative extras. A quick search on-line shows this book goes for about $75.00 USD everywhere.

Don't forget nothing compares to OJT when it comes to installation. It's always best to apply in the field what you've learned from a good textbook first.
http://www.powells.com/cgi-bin/biblio?show=HARDCVR W/COMP MEDIA:NEW:9780826912879:75.00

TnAndy wrote: »

Rick,

Here a good "textbook" on solar......it actually IS a textbook for some solar courses, and is set up that way with practice questions at the end of each chapter, but it's also a good self guide as to the basics of components and how they mesh together to make a system. Worth the money, IMHO.

Solar Book Here

Some information on NEC and how it applies to solar power:

PV and the 2005 NEC -- Reference Document

And, of course, the NEC Code Book (current edition or version that is used by your locality).

-Bill

PS: Our host also has a Book they recommend:

Book - The New Solar Electric Home

PPS: From another poster:

KeithWHare wrote: »

I recommend "Photovoltaics: Design and Installation Manual" from Solar Energy International. This does a pretty decent job of explaining everything except for battery banks.

Keith

PPPS: From another website, I saw this Boatowner's Illustrated Electrical Handbook recommended.

PPPPS:

rollandelliott wrote: »

according to wikipedia once it is adopted into law by a particular govt agency it becomes public knowledge

http://bulk.resource.org/codes.gov/ga_electric.pdf

is one link

there are many more specific to certain states/cities here

http://bulk.resource.org/codes.gov/

May 26th, 2013:

ChrisOlson wrote: »

I always recommend Hugh's recipe book
http://scoraigwind.com/axialplans/index.htm

It has the "plans" on how to build six different turbines. But Hugh also goes into the theory in explaining why the turbines are built the way they are, and it's written by a master that has spent most of his life working with wind power.

I don't know about the Otherpower book - I have only read excerpts of it and never the whole thing.
--
Chris

June 30th, 2013:

ChrisOlson wrote: »

Ed Lenz's website is probably the best resource for building a small microturbine. Ed has articles on there covering three-phase basics, along with several small windpower projects he has done, etc.
http://www.windstuffnow.com/main/

--
Chris

July 19th, 2013:

Panamretiree wrote: »

A good manual on boat electrics is: Boatowner's Mechanical and Electrical Manual: How to Maintain, Repair, and Improve Your Boat's Essential Systems by Nigel Calder. Goes through all issues that you can be confronted with, including solar, wind and hydro power. Has considerable information on grounding and bonding in a boat. Approximately $36.00 on Amazon.com.

Cheers

-Bill

zoneblue

Re: Want book recommendation on off grid design

Wow. Ask and ye shall receive

westbranch

Re: Want book recommendation on off grid design

Bill, that list would, in and of itself, make a Great Sticky.. way to go.

WillBkool

Re: Want book recommendation on off grid design

I agree, good post. Definitely should be a sticky.

odys99

Re: Want book recommendation on off grid design

Wow- watch out what you ask for, you just might get it. Thanks a lot, Bill. Now I have my reading cut out for me, and I have to decide just what loads to instal in my (as yet unbuilt) cabin. I'll be back with, hopefully, intelligent questions to ask.

Thanks again

BB.

Re: Want book recommendation on off grid design

I have posted information about books in the:

Working Thread for Solar Beginner Post/FAQ

among other stuff there...

If anyone else wants to add their favorite information to that thread, please feel free. Someday, perhaps the thread fairy will go through and make a nice FAQ out of it.

Odys99, I (we) did not intend to push you out there without any help.

There are many ideas and folks out there that can give you some good starting points. Energy usage is highly personal, so we try not to answer "how we would do something"--Because you may not find our solutions fitting your needs.

People have a very poor "feeling" of power usage and generation. A desktop computer/server running 24 hours per day may use 4-5x as much power as a 25 cuft full sized (North American) refrigerator/freezer. Making accurate measurements will be a big help in understanding your needs, and what you are will to pay for.

Just to give you some ideas on general energy usage:

• 1,000 WH per day (30 kWH per month): A small cabin with lights, laptop, radio, water pump to pressurize plumbing
• 3,300 WH per day (100 kWH per month): Add a full size 120 VAC Refrigerator/Freezer, "reasonable" well pump, washing machine--About the minimum for a "normal" electric power experience
• 10,000 WH per day (300 kWH per month): Add more people, a second freezer, TV+DVR, desktop computer, possibly even some heat pump heating/cooling/hot water
• 33,000 WH per day (1,000 kWH per month): A "typical" north American home
• 100,000 WH per day (3,000 kHW per month): Heavy A/C usage in a hot climate, swiming pool pump, electric water heater, etc...

For a weekend cabin, you probably would aim at 1,000 WH per day.

For an off grid home occupied 9+ months a year--Around 3,3000 kWH per day

For a full home with kids, and some creature comfort--10,000 WH per day.

A 3,300 WH per day system is not cheap--Probably around $10,000 to $20,000+ dollars worth of hardware+batteries+etc... Add a bit more if you pay somebody to install (systems larger than ~3.3 kWH per day, you should look closely if you have the knowledge and skill to install vs hiring somebody else--Especially if this is your first rodeo. And you need to replace the battery bank every 5-7 years or so, and electronics (charge controllers, inverters, etc.) every 10+ years (ongoing expenses).

Roughly, if you add up all the expenses (installation, maintenance, battery replacement for 20 years) and divide it by the amount of power you use over 20 years, you will get around $1-$2 per kWH, although a few folks here have gotten well under $1 per kWH for their estimated power costs.

When you compare to utility power at $0.10 to $0.20 or so per kWH, off grid power costs around 10x as much.

With power cost for off grid power so high--you can see your appliance selection is very important (electric coffee pot, perhaps not, A/C--Not on a small system, LED lights instead of filament, efficient $1,000-$2,000 well pump vs "cheap" jet pump, etc.).

I hope this helps. The numbers are very rough, and as I said, others may have different opinions/results (I, and the other moderators, are not in the solar business--We have nothing to sell)--But for a first look at your loads and potential budget--They are "good enough" to at least get you in the ball park before you really get down into the numbers for "your system" (looking up costs, selecting hardware, etc.).

Please ask questions and let us know how your plans are going. We are here to help and learn ourselves.

-Bill

odys99

Re: Want book recommendation on off grid design

Thanks again Bill. The books you recommended will give me a good start.

I was quite aware that I would have to start with an assessment of my actual uses, so as not to deplete the batteries on a regular basis, and be able to recharge them readily with enough panels.

My main desire is to learn about how all the components work and work together so, once I've determined my loads, I'll be able to work on design. I'm the kind of person who wants to know the principles behind the workings before leaping in, and that will take study.

But, just to get a bit specific on my particular instal, my cabin is about 500 feet away from where the panels will need to be installed, because of geography, trees, etc. So, I will want to design with keeping wire costs to a minimum. I suppose the way to do so is bump the voltage up from the panels by placing them in series, so that with higher voltage I can run current up the hill in lesser size wire. So, as you can see, I'll need to be familiar with the principles involved. As well, I want the system to be scalable, so later I can add panels without pulling new wire from the panels to the charge controller. At some point I'll have to decide just how large a wire size I want to pull through that conduit, planning for both the present and anticipating the future. So, I'm going to have a lot to think about.

Any initial thoughts on such a scenario would be appreciated.

Thanks again.

BB.

Re: Want book recommendation on off grid design

A higher end MPPT type charge controller with ~140-150 VDC maximum input voltage can usually take an array with around 100 VDC Vmp-array maximum for most areas. Places that never get very cold may accept a higher voltage array.

And there are higher voltage controllers from Midnite with 250-~295 Varray-cold max voltage:

http://www.solar-electric.com/misoclchco.html

And there is a Schneider 600 VDC input MPPT controller (~400 volt Vmp-array).

http://www.solar-electric.com/xaxwmp80amp6.html

There are some other ways of doing this with SMA's Sunny Island system--But that is usually a bit "pricey" for a smaller system, especially outside of Europe (but it is very nice--Especially if you need a distributed AC power system for a small group of homes/work shops/etc.):

http://www.solar-electric.com/smasunnyisland.html

Lastly--There is building the power system at the array (panels, chargers, inverters, battery bank) and sending AC power from the array to the home (120/240/480 VAC etc.).

The drawback is the system is 500 feet away--A trek to check/maintain the system, figure out what you are going to do for AC backup genset, etc. But it can be done.

-Bill

odys99

Re: Want book recommendation on off grid design

Thanks Bill that's a great start.

zoneblue

Re: Want book recommendation on off grid design

Roughly, if you add up all the expenses (installation, maintenance, battery replacement for 20 years) and divide it by the amount of power you use over 20 years, you will get around $1-$2 per kWH, although a few folks here have gotten well under $1 per kWH for their estimated power costs.

When you compare to utility power at $0.10 to $0.20 or so per kWH, off grid power costs around 10x as much.

Just for kicks and giggles heres a shot at the 20 year cost of our off grid power.

Grid rate here is NZD 0.32/kWh, (including line charge at low user rate) increasing at 4.98%pa (09-12).
Energy produced 4.6kWh/day, average.
System cost NZD 9800.
Discount rate 5%.
NPV of system including 7 yr battery replacements, 15 year other hardware is NZD 13,941.
"Cost" of energy produced= NZD 0.42/kWh.

That doesnt factor my labour, but nor does it factor the high grid connect charge (21K). All told, not easy to call with regards to being economic.