Two words: RED DAWN.
This is a discussion on Group Think! Duration of SHTF! within the Off Topic & Humor Discussion forums, part of the The Back Porch category; Two words: RED DAWN....
Less Than a Week
One to Three Weeks
A Month or Two
More than Two Months
Whoops! I Forgot to Plan!
Two words: RED DAWN.
07/02 FFL/SOT since 2006
Now you've done it; I've got "Red Dawn" on tape and I may watch it tonight. Then again, "Man on Fire" and "Collateral" wouldn't be bad choices either.Originally Posted by freakshow10mm
keep in mind that there are situations where a small underpowered engine will have to work much harder burning more fuel per hour than an overpowered unit that doesn't break a sweat doing an equal amount of work.Originally Posted by Tangle
Red Dawn: The only movie in which Patrick Swayze wasn't a pansy.Originally Posted by Tangle
Saw Collateral. Decent movie. Liked the gunplay, not as well as Heat. Not a Cruise fan though. Denzel neither. Heard Man on Fire wasn't really that good. How'd you like it?
07/02 FFL/SOT since 2006
"Man on Fire" wasn't that good?????? I bought the DVD and must have watched it 6 or 7 times, not in a row of course; over a period of months. I thought it was good.Originally Posted by freakshow10mm
Like anything from Hollyweird, it's gonna be larger than life.
I consider Red Dawn to be a classic! Man on Fire is also very good, but in a different genre. Worth watching if you haven't seen it.
pjward did a good job of saying what I was trying to, in a much simpler, straight forward manner.
But. . . My wife has decided to make it much easier for me! She's decided that the generator does NOT have to run the whole house, heat-pump/AC and all. I can now scale it down to "survival mode" and just supply power for a more realistic version of the necessities.
This means getting one that will power the 'fridge, a couple of florescent lights, air pump for the ponds, and the well, with the well being switched on only "as really needed."
Doing it this way, we can cut our power needs just about in half. And as far as the air temps go, I think I can "splurge" by making sure the well circuit is off and maybe run the heat-pump/AC for an hour or so in the early afternoon and again just after sun down, and keep the house at a pretty "live-able" temperature this way.
I think the total cost of getting the larger system together made her re-think the situation.
Sure makes things much easier for me! Heck of a lot cheaper, too.
Political Correctness has now "evolved" into Political Cowardice.
I've heard the small engine working harder than a larger engine theory before. If that were true, then it would be reasonable to assume that as engines got bigger and bigger, they would get more and more efficient and burn less and less fuel for a given HP output. Hence, according to the fuel consumption figures we've been looking at, to generate 10 HP, a 10 HP engine might consume 1 gal per hour, a 20 HP engine should consume about 0.5 gal per hour and a 40 HP engine should consume about 0.25 gal per hour. Do you see a problem developing here?
Here's another perspective. To generate AC power at 60 Hz as needed for the home, regardless of size, the engine has to run at 3600 rpm or the AC frequency won't be right. So the bigger engine has to turn the same RPM as the smaller. It simply takes more energy to rotate the components of a larger engine due to the bigger cranks, bigger pistons, etc. For example, if we removed the spark plugs from a large and small engine so we don't have to deal with compression issues, which do you think would be easier to rapidly turn by hand, a 10 HP engine or a 40 HP engine? Well the fuel has the same issue, it has to overcome the heavier components of the larger engine just like we would.
Working harder may mean the smaller engine will wear out faster due to higher bearing and stress loading, but I seriously doubt a smaller engine is half as efficient as a larger engine.
Honestly, I think there's a mix up in the fuel consumption specs.
The effciency curve is probably a parabola, eventually it will flatten out.
"I am a Soldier. I fight where I am told, and I win where I fight." GEN George S. Patton, Jr.
It is extremely difficult for me to believe a 20 HP engine (Honda GX-620), turning the same RPM (3600), generating the same amount of power (assuming the larger engine is generating the max power of the smaller engine) is over twice as efficient as the very same style and brand rated at 11 HP (Honda GX-340).Originally Posted by tanksoldier
I could accept numbers like 10%, 20%, but not over 100% more efficient. I believe somebody messed up some specs.
The laws of physics are just that - laws. I believe you are right, sir!Originally Posted by Tangle
OK, so how does one come by the "real numbers?" No realistic planning, therefore no action can be taken without real-world numbers to work with.
Going to Honda for answers wasn't productive and it looks to me like all the web sites that sell generators get their specs from the same source.
I don't know if this subject is one that much of anyone has any interest in, but if it is, I think it should continue in a thread of it's own. We've wandered a ways off-topic from the poll question.
If I come up with any more thoughts or ideas, or usable info, I'll start another thread if no one else does.
Political Correctness has now "evolved" into Political Cowardice.
Hey - we're all learning! Interesting nonethe less!Originally Posted by madmike
mm,Originally Posted by madmike
It is frustrating because the published numbers are suspect and we can't seem to find out for sure. I'm interested in this too don't forget. I wanted a 7-8 kW gen. but I'm not about to buy a 7-8kW gen if I can get a 13kW gen that consumes half the fuel a 7-8kW would. I find it interesting that Honda publishes fuel consumption numbers for the GX-620, but don't give the GX-340 fuel consumption numbers.
I had a really busy week last week, but maybe this week I can put some time in effort into this. I don't know what I can do that you haven't already done, but maybe somebody will get lucky.
And, like Rock and Glock said, we're all learning and it is interesting.
I guess we kinda need to hurry though, hurricane season is getting closer.
Iím coming in late to this discussion but it is still fascinating.
As far as the original poll goes, I figure a real SHTF situation is more than two months. Katrina was kinda like that. I am thinking we could be in for real trouble if Iran, N. Korea, or China decides to lob a Nuke over the home land and detonate about 100 NM over the surface. (Not a surface hit.) No need for accurate targeting there. The Electro-Magnetic Pulse would shut down every Computer chip and power grid in line of sight of the detonation. No power, no transportation, no communications except for hardened systems; welcome back to the 1800ís. Now, assuming there is no ďinvasionĒ following, we are still in for a serious time of it.
My personal (family) preparation at this time is only up to about a month of food, water, and hygiene provisions. Got plenty of ammo if needed. We try to keep at least 1 month dog food on hand although timing is important because we breed and sell pups from time to time. If there is a litter on the ground, thatís going be tough, a full litter can eat up to 40# a week at 8 weeks of age. Besides, I canít see people buying a puppy in the midst of a SHTF situation. (For that case, I might have to record a few ďrecipesĒ from a Vietnamese friend.)
We also make our own wine and have about 100 bottles in the cellar at any given time as well as the equivalent of about 200 bottles brewing in the carboys. (SHTF? What SHTF? Hic! ) Because we make wine from kits, we reuse the big Mylar or heavy plastic juice bags to store water. So far I think we have 50 gallons bagged, add the water heater tank, we have plenty of drinking water for several days. Baby wipes are for cleaning & hygiene. The chest freezer is only 20 cubic feet, so it will have to be consumed first & hope for little loss. A friend, who is an electrical engineer, has developed a single 12v car battery powered power supply that can probably extend the freezer a few days. (His power supply has been demonstrated to power a Rock Band, three guitars, two pianos, electronic drums and full amps for about 3 hours without putting a dent in the battery capacity.) Iím working on getting one for myself to use as a backup for my computers.
My perfect preparation is more like 3 months provisions, hand pump well for water, propane for the grill and live in an underground shelter. That will involve moving to the country, but we can dream I suppose. Till then, I do the best for suburban living.
Iíd love to be able to eventually do the power generator thing, but until then, I plan for powerless provisions, like I do for hunting. $$ is the issue these days. (A country boy can survive.)
Itís so much easier now days, to "Love and honor" my wife, when she is armed, and shoots a better group than I do. (Till death do us part, eh?)
ďThe way you get shot by a concealed weapons permit holder is, you point a gun at him,Ē the Sheriff said.
I hate to be the one that keeps saying something doesn't look right here, but something doesn't look right here. First, a 12V car battery is not designed to be used in a deep discharge application such as a long term power conversion and supply. A few deep discharges will kill the battery. (I should mention that I worked for five years in a huge electric vehicle test program) A deep cycle battery is built to handle the deep discharges, but OTOH, doesn't make as good of a cranking battery.Originally Posted by elkhunter
Second, to convert 12 volts to 120 volts is a 10:1 conversion. The power supplied by the battery will always be more than the AC power it supplies. For example, a table shows that a freezer draws about 700 Watts. Hence, the battery has to supply more than 700 Watts because the convertor is less than 100% efficient. But, even assuming 100% efficiency, in order to supply 700 W, the battery would have to supply a a bit over 58 amps! 12 V x 58 amps = 696 Watts. The cables connecting the battery would have to be the size of welding cables. The battery might last an hour minutes at this rate.
There are no ways to get around the fact that input power must always be greater than output power and so one can basically divide 12 volts into the power required out to determine how much current will have to be supplied by the battery. A group 24 size deep cycle battery is probably a bit larger than a car/truck cranking battery, and is rated for about 1.7 hours at 25 amps. At 58 amps it's gonna last about 40 min. Of course if the device it's powering only runs 20 minutes at a time or so, it's gonna last a while longer.
Power inverters (12VDC to 120VAC) are available from a lot of places and the technology is very mature. I'm an electronics/electrical engineer and I build lots of electronic stuff including an all MOSFET power controller that can handle 800 amps in-rush current from a 24 volt battery pack. I doubt even with my sources/resources that I could build an inverter for what I could buy one for.