Reference books and books for beginners.

Re: Reference books and books for beginners.

BB,

Thanks for the thorough reply.

1.Measure/quantify your loads (peak, average watts; energy use per day in Watt*Hours, etc.).

Will get started.

2.Conservation, conservation, conservation. Insulation, new energy star appliances, turns stuff off when not in use, etc.

I have teenagers... nuff said... I do have separate services to my shop and barn vs. my home so it does make monitoring a bit easier.

3.Repeat #1 and #2.

4.Define your needs... If the grid fails, do you need 100% of your pre-fail power usage? Or can you live with a lot less.

We can live on a lot less, we as a family spend many hours outdoors so electric can be reduced to food refrigeration, lighting and air circulation. I am mainly looking at long term grid outages, weeks, months, etc. Short term is not an issue as I have a backup diesel welder/generator (11kW continuous) with 1200 gallons of diesel.

5.Alternative fuels... Heating (home, hot water, cooking) with alternative fuels is usually cheaper than with solar+battery+generator

Our primary heat is wood, generally I have between 10 and 30 cord split and stacked depending on the time of year. it has really kept the electric bills down in the winter versus when we first moved out here. We can also cook with wood and there are plans to improve that.

6.Do a paper design (or three) for systems that meet your needs (don't pick hardware yet, just use rules of thumbs designs and decide which version will best meet your needs--Do some cost estimates--Costs are a huge issue with off grid solar--$/kWH pricing for off grid solar is around 10x the cost of utility power--You need to be very sure that every kwH you feed your loads is "cost effective").

I will have a lot of question on that as I progress.

7.Pick hardware and review design results with your needs.

8.You may wish to stage a roll out... a) genset, b) battery bank+Inverter/Charger, c) solar array etc...

I have main generator as mentions, Miller Trailblazer 302D (Kubota D722 engine with 11kW continuous) and fuel, also I have a small cheapy 3.5 kW for camping that runs on gas. But no bulk gasoline so that is only short term. We use it at deer camp.

9.Monitoring... If you do not (or cannot) monitor your system (especially power usage and battery banks--weekly/monthly checks of water levels, specific gravity, electrical connections, state of charge, etc.)--You can end up with a ton of scrap lead in a few months (if not weeks or even days with a major "oops").

10-4!

10.Upkeep/repairs... Solar panels may last 20-40 years, but batteries may last 3-5 years for "cheap" ones, 8-10 years for expensive ones, and 15+ years for industrial traction batteries. Inverters, charge controllers, electronics--Plan on replacing every 10+ years, with possible repairs in the 10 year period.

10-4!

Re: Reference books and books for beginners.

BB. wrote: »

I don't want to put the cart before the horse (measuring, conservation, planning)--But generators are one of those things that are (relatively) cheap to buy but can be dear to run...

Your 11 kW unit may run on 1-2 gallons of fuel per hour--And lightly loaded diesel (less than 40-60% or rated load -- another rule of thumb), they can wet stack, carbon, glaze cylinder walls, etc.).

Energy usage is highly personal... For me, I would love to have a battery bank+off grid AC inverter--But I have may be 2 hours of outage every few years. An off grid system does not make sense for me. Because, for the most part, I don't use a lot of power (natural gas for everything heating), a Honda eu2000i (1,600 watt) genset that will run 4-9+ hours on a gallon of fuel (1.6kW to ~400 watt) is great for me. Plus it is portable (for us, earthquakes can red tag a home--can't take the solar system with me). And I can use fuel from the cars or use my 20 gallons of stored fuel to cook and/or bug out. (and California is almost making fixed backup diesel gensets illegal out here due to pollution regulations).

But I live in a major metropolitan area with temperate weather conditions--So my needs (and failure modes) will be different that you.

In your cause, once you understand your "base power" needs--You might look for that (somewhat mythical) 3-4kW diesel genset, or a 2-4 kW genset to run on propane (if you have it) or even gasoline (don't know how cold it gets in winter for your area--Gasoline can be easier to start/run in very cold conditions vs diesel or propane).

Anyway--just part of the discussion.

-Bill

Thanks, I am very aware of engines and their limitations, both diesel and gas as well as long
term storage of such fuels. I have actually several options for auxiliary power, PTO driven
generators (I own 5 tractors, 3 gas, 2 diesel/4 antiques and one modern, the modern 2007
New Holland is diesel). I also have a fully equipped machine/fab shop, less a set of powered
rolls and a hydraulic press brake (still on the want list). I am zoned ag and as a result have
separate electric services (meters) to my shop and my home both are 400 amp services, not
that I will ever use 400 amps in the house, there is a story there involving a storm and very
hungry Comed workers... And while I have never used 400 amps in the shop I have exceeded
200 amps on many occasions, but I am not looking to run the shop off a PV system, I don't
think I have enough acreage for all the PV panels needed for that application. I do not
have natural gas, propane or "fuel oil" as options not do I want to add any of the above. I do
have 900-1200 gallons of diesel fuel at any given time here, usually not much more than 20
gallons of gasoline. Temps can be from 105F in the worse of the summer to -35F in the coldest
part of the winter. I have what I need to cover both extremes. House is well insulated now
but will be better after the renovation.

What I am looking to do is not a system to cover my butt for a day or two or even a week of
outage; my generators will easily cover that for me now with what I have. What I want is a
fully DC system that will provided me services for months or years if the grid goes down for
a long time. Again I do not think this is the place for a socio-political discussion.

My view is to set up a DC system (right now I am leaning toward a 24V system) that will power
necessary loads such ceiling fans, blowers, lighting, refrigeration and well pump all being DC;
but this be an every day system up and running. Then have the "comfort" loads, dryer, hot
water heater, microwave, TV, Play station (kids), baseboard electric heaters, etc. run off con-
ventional 115/230V AC. Having both 115/230AC and 24VDC wiring in the house. Now if I can
get any excess DC converted to AC and spin the meter backwards I would not be opposed to
that either.

We raise organic foods now, chickens, beef, (considering hogs) and all kinds of fruits and veggies.
We have 2 freezers and 2 split freezer fridge units now to keep all the food we harvest and hunt
for now; I would like to over the next few years convert those to DC units, they are all AC right
now. Not to mention shelves of canned, pickled and fermented foods.

Re: Reference books and books for beginners.

mtdoc wrote: »

I am in a similar situation as yours - electrical service at end of long rural road with occasional extended power outages. I also share your concerns about extended grid failures in the future. A few points:

As BIll points out - You need a full accounting of the loads you expect to power.

On the top of the list.

As Vtmaps alludes to = A DC system may sound more efficient but in reality unless your are powering small loads a short distance from your battery bank (think motorhome) it is not the right choice.

I understand that DC does not transmit well over distances, I am a very experienced
welder and understand the size copper needed for high current conductors So my
plans on locating my Controls and load center are fairly central in my home, with that
my extreme run, (and yes I am including the vertical distanced (walls) as well as
horizontal runs as well) is 50 feet and that would be the ceiling fan/lighting in my
master bedroom. Bigger loads like the refrigeration would be under 25 feet as would
the blower in the duct work. My house is an L shaped ranch and the DC load center
would be in the inside corner of the L.

Based on your description so far, you do not want to do a 24V system - trust me on that. 48V is what you will want - I suspect the regulars here with 24V systems will agree. These days the cost savings of a 24V inverter/battery bank is not enough to offset the loss of efficiency and extra copper costs, etc for anything but very small systems.

This is why I am here, I do completely understand that P=VI, and wire size is dictated
by current. I also am the type that if 3 gauge is code but borderline for what I will
running off it I have no issue with running 2 gauge. That is what I did do for my 100
service to my TIG Welder, and now you know why I have a 400 amp service to my
shop, and that is only one of the 2 welders I have that is not counting the air compressor
machine tools, plasma cutter, lighting, fans, etc... I digress...

Cost of copper while I do not want to waste money I have no issue with spending extra
on wire as it will out last my lifetime, I am 46. Something like PV panels, I will have to
replace at least once before I die, Inverter/controls a couple of times, batteries several
times. I read in another thread about using cheaper batts on your first bank so you can
gain experience with a minimized cost before you really get into higher cost batts; I like
that idea. I do look at lifetime costs.

Now most of the appliances I have seen, and I have not exhaustively looked, seem to
be for 24V system. If I go with 48V distribution are there appliances that come in that
voltage or are they like a lot of 3 phase equipment where you can wire accordingly?

Or can you wire it up like the typical 115/230 center tap AC residential system where you
would have a +24V leg a -24V leg and a neutral leg, and where you need 48V you use the
+ and - legs or with DC does that not work with chassis grounds? (I am learning DC)

Take at look at my sig. My system powers a modern 3000 sq foot energy efficient home (Sans heat) with ave Daily loads totaling 5-8 kWh.

Thanks.

Re: Reference books and books for beginners.

Cariboocoot wrote: »

Actually welders are inductive: your basic welder is a great big transformer.

The load (actual welding process) puts a resistive load on the transformer or inverter. None
of my machines are transformers, one is a generator the others are inverters, better arc and
control. So even if there is a transformer, the end load is still resistive.

icarus wrote: »

Just a comment, please watch your language, and indeed keep the political comments to a level to where they are only relevant to the thread.

Icarus

Sorry about the language, but I have tried to take the salt out of the sailor, but with little
success. I was trying to avoid the political stuff, but I could not think of a better explanation.

Re: Reference books and books for beginners.

mtdoc wrote: »

OK, I get the prepper bit - I have some prepper tendencies myself..

You still should build a system of only AC loads and here is why:

AC appliances are not only much cheaper and more efficient, they are more common. If things fall apart it is going to be much more difficult to replace DC lighting and appliances than AC. All those folks without power are not going to have much need for their unused AC stuff, are they?

Had not thought that way, that is a very good point.

If you're worried about inverter reliability over the longer term - use the money you save not buying DC appliances and buy a back up inverter.

If 10 yrs after the grid goes down your inverters are dead - well if there is not enough tech available to repair or replace them then finding batteries will be an even bigger issue.

Finally - if we end up going back to early -20th century, pre-petroleum technology- you can always make (or have made) some simple DC lighting, motors and other DC electronics using salvaged parts from all the scrap electronics that will be lying around...THEN it would be the right time to go DC (may Nicholas Tesla rest in peace!) 8)

One question, how efficient are inverters taking DC power from the battery bank
and converting back into AC power? I was thinking it was in the 70 percent range.

Re: Reference books and books for beginners.

icarus wrote: »

IMHO the flaw in the total package logic is, assuming you don't have fuel or grid for several years, where are you going to source replacement batteries in an end of the world scenario? I would posit that battery procurement might be much harder than fuel, since one has fuel alternatives, like bio diesel, veg oil, wood and coal gasification etc. I can see making other fuels a lot easier that I could see making batteries.

Icarus

What is the life cycle on batteries 3-5 years for cheapies, even well maintained. Ten years
or more for good ones? Like Surettes. Lifetime for iron nickel? (a little extra electrolyte is
easy to store) not like I have that kind of budget. Maybe if I win the lottery big. I am a chemist
battery chemistry was literally Chem 101.

Preppers stock up on everything.
I do have plans for getting at least one full set of extra lead acid batteries purchased with out
electrolyte in them, store them dry (they would have an indefinite shelf life; longer than I will
live) and when needed add the sulfuric acid and instant battery.

Not really planning for "End of the World" more of a fiscal collapse followed by a societal
collapse. I figure once society collapses it will be 2-3 years before it will starts to rebuild itself.
If the Yellowstone caldera blows or a big meteor or comet collides with the earth, we are
toast and will not likely survive anyway. Socio-political collapse is what I am worried about.

Twenty years ago I would have thought I was a crack pot; and maybe I have become one...

Re: Reference books and books for beginners.

Okay back to step one, analysis of loads. Yes, I know this is not an in depth analysis but
I am working on that, issue is my biggest power hogs are 230V loads, well, hot water,
stove, oven, etc.. I am researching equipment to analyze those loads. The 115V 15A
Kil-a-watt meter is not much help. This is just an overview of my total consumption. My
wife who cannot throw way anything has our electric bills back to 1997 in the filing cabinet
and I am sure she has the back to 93 or earlier some where. What is interesting is the
kWh usage is not all them much different other than the summer and winter peaks, well
post wood heat at least.

The attached file is the kWh used in my home by month. Now you have to keep in mind
that my home is all electric, no natural gas, no propane, no fuel oil, I do try to heat with
wood, but my wife is eternally cold...

I have not done any serious conservation measures yet, that will be done with the house
renovations. Mostly what I have done is as appliances are being replace we have replaced
with energy star appliances, stove, microwave, washer, dryer and the main chest freezer
all are energy star rated; the fridges are not, yet, nor is the really old upright freezer but
that is empty and off most of the year. I am stilling thinking that DC chest freezers could
be a good choice, transmission will not be an issue because they will be parked next to the
inverter and battery bank, they will share opposite sides of a wall.

Now I have a shop and barn they exist on a separate service and meter so this is just the
house loads. My prospective PV system will only service the house. If I ever get to a PV
system for the barn and shop it will be completely separate system.

Now for those faint of heart about energy consumption, sit down before viewing my graph.

Attachment not found.

And I have no idea what the heck happened in Nov and Dec of 2010?