How long can a car run at idle (stationary) to charge a battery bank like a Delta or two?

[gfmucci]

Maybe a good thing for the idle to increase and let the ecu do what it thinks is best otherwise running out of fuel won't be what stops the vehicle!
I have 2 sets of jumper leads built-in ready for the apocalypse or when the car lights get left on.
Today's vehicles are different and I'm not sure what are the problems associated with long term idling, if any, since that's what city cars do most of the time anyway. In an emergency why not?

Glazing of cylinders was a problem in older vehicles, probably still is in diesel engines.
Make sure your vehicle is outside, carbon monoxide is insidious.
Siphoning from your tank can block the filters from plastic scraped of the hose after a number of times.

You and I are on the same wavelength concerning the impracticality of siphoning from modern vehicles as well as infrequent dire emergency use and practicality of using direct car power for SHTF situation.

Most of the advice from others in this thread assumes that using the car's electrical system for my purpose would be a daily, weekly, or monthly operation when in fact it would be a rare, next to last resort action every few years at most - just prior to resorting to pure solar panel usage.

 

[NwCali]

airflow so having the hood open and even a small 12v fan blowing on alternator would help

Well, first off some cars have the best airflow with the hood closed...

And using the alternators current to cool itself seems counter productive, meaning the fan will put more of a load on the alternator.

Not wanting to knock your idea, but without doing a control test you'd never know if it actually was better or not.

Long ago I thought a vacuum cleaner worked its hardest when you put your hand over the end. Indeed it actually is not its hardest (most amps) draw. That is when its moving the most air it can move.

 

[sunshine]

To use in a rare, one off event every few years as is my purpose, your assumed level of required efficiency is irrelevant.

Probably would be the best solution, financially and environmentally, to the problem....and will always be a backup to any other proposed answers.
I had already written the above before your latest reply...still will let it stay!!

The best part of some of the negative replies is that often they contain info that may be relevant to the question or even to some other problems.

With EV's the two way connection to homes will be the norm.

 

[noenegdod]

From wattstreet.com and many sites that cover the same topic:

Due to the lower energy density, you need to run propane faster than you will gas a model, which is called fast burn.

Because of fast burn, propane generators are less efficient than gas generators as propane models can produce fewer BTUs per gallon of fuel.

You really dont have a clue what your talking about, have a grasp on what you quoted or understood anything in my post. As you said earlier, your not mechanically inclined and have no interest in it. Your out of your depth on this subject so you should probably stay silent on it until you are willing to put the effort into actually understanding the subject.

 

[DerpsyDoodler]

delete

screw this ass inine thread.

 

[sunshine]

Long ago I thought a vacuum cleaner worked its hardest when you put your hand over the end. Indeed it actually is not its hardest (most amps) draw. That is when its moving the most air it can move.

This would also go against my thinking,
Fans burn out when the blades are impeded.
Compressors draw max amp at startup.
Please enlighten me!

 

[sunshine]

What is the reason they don’t work?

I haven't been able to siphon any modern vehicle for at least ten years....that was when my neighbour's car came with a petrol cap lock.

 

[Alphacarina]

With regard to propane vs gasoline for powering small generators, I do know that a given engine puts out less power when running on propane than when it's running on gasoline. Onan makes a 4Kw generator for RV's and they also make an identical version of that same generator for propane and it's only rated at 3600 watts. It also uses more fuel to generate 3600 watts than the gas version does to generate 4000 watts

Designation​	Model​	Fuel​	Watts/Amps​	Fuel Use (half load)​
RV QG 4000​	4.0KY-FA/6747​	Gasoline​	4000/33.3​	0.5 gal/hour​
RV QG 3600 LP​	3.6KY-FA/26120​	Propane​	3600/30.0​	0.6 gal/hour​

Don

 

[noenegdod]

With regard to propane vs gasoline for powering small generators, I do know that a given engine puts out less power when running on propane than when it's running on gasoline. Onan makes a 4Kw generator for RV's and they also make an identical version of that same generator for propane and it's only rated at 3600 watts. It also uses more fuel to generate 3600 watts than the gas version does to generate 4000 watts

Designation​	Model​	Fuel​	Watts/Amps​	Fuel Use (half load)​
RV QG 4000​	4.0KY-FA/6747​	Gasoline​	4000/33.3​	0.5 gal/hour​
RV QG 3600 LP​	3.6KY-FA/26120​	Propane​	3600/30.0​	0.6 gal/hour​

Don

Don, what modifications were done to the generator. Was static compression raised to optimize it for propane? Was the ignition curve optimized for propane? Or did an engine that was intended for gasoline simply have its fuel system swapped out for a propane system?

That said, propane engines will always be de-rated compared to an identically optimized gasoline engine. Why? because propane enters the combustion chamber as a gas, displacing and therefore reducing the amount of air you are able to introduce into the chamber. A portion of the gasoline introduced into the combustion chamber remains liquid until after the valve closes therefor not displacing as much air. More air+more fuel+ bigger bang.

Still does not change the fact that an optimized propane engine is more efficient than a gasoline engine. Remember: Efficiency is ENERGY out/ENERGY in, not energy out/volume (liters/gallons) in.

 

[OM617YOTA]

In my vehicles, I consider half tank to be my "empty" and refill at that point. Stuff happens, and a half tank gives you options even just during normal life. If your car is plan C for backup power, this might be a good system to adopt.

 

[evad]

If the situation is so bad that you have exhausted al other sources of power having a car with a empty tank might not be the best solution.

 

[alfaeric]

From wattstreet.com and many sites that cover the same topic:

Due to the lower energy density, you need to run propane faster than you will gas a model, which is called fast burn.

Because of fast burn, propane generators are less efficient than gas generators as propane models can produce fewer BTUs per gallon of fuel.

That really only covers fuel flow, not efficiency.

If an engine was optimized for propane, since propane has an octane rating of 110, you can always run closer to best spark, helping the thermal efficiency. And it was pointed out that propane enters the intake as a gas, but that can also be used as an advantage as you can run more open throttle- lowering pumping losses.

As for the "fast burn" thing- most people take that meaning very wrongly. Still, the rest of the sentence may be correct, but, again, that's about the fuel flow, not efficiency.

And, as I posted before, any generator running at in it's designed output range will be more efficient than a car running at idle due to how an engine runs at idle.

But even making it a financial efficiency thing- propane is so much cheaper than pump gas, even with increased flow, it would be more financially efficient.

 

[alfaeric]

OP- the reason nobody knows this is that nobody has ever really done it. Even in development, cars are not left to idle until they run out of fuel. So it's really hard to calculate how long it will run.

But, if you really want to know, what you can do is get an OBD monitor system, and watch the fuel flow during idle. From that, you can calculate how long it will take to empty the tank.

For what you are asking, yes this will work- and given your constraints, it's a good choice. As pointed out, there are better options- but all of them cost money and storage for minimal use. So not adding to your system, charging a 12V battery system with your car will work in a pinch.

 

[gfmucci]

You really dont have a clue what your talking about, have a grasp on what you quoted or understood anything in my post. As you said earlier, your not mechanically inclined and have no interest in it. Your out of your depth on this subject so you should probably stay silent on it until you are willing to put the effort into actually understanding the subject.

You remind me of a famous line: "You can't handle the truth." Torqued much? (That's a mechanical term.)

 

[noenegdod]

You remind me of a famous line: "You can't handle the truth." Torqued much? (That's a mechanical term.)

Its not truth I have a hard time handling. Its when someone is insisting something is the truth but have 0 ability to explain it. Not that having faith (in the right things) isnt important but when someone believes something is true but they are no ability to explain it, they are simply religious. It doesnt make it true.

Thanks. Great advice for a mechanic, which I am not and have no desire to be.

and now your using "mechanical terms"......

Keyboard hero.

 

[gfmucci]

Its not truth I have a hard time handling. Its when someone is insisting something is the truth but have 0 ability to explain it. Not that having faith (in the right things) isnt important but when someone believes something is true but they are no ability to explain it, they are simply religious. It doesnt make it true.

and now your using "mechanical terms"......

Keyboard hero.

No desire to be your level of "master mechanic." I don't have time left to know all that you know. And I do understand how those who believe they are at the top of their field can be very touchy and easily provoked with others who are not up their standard.

 

[noenegdod]

No desire to be your level of "master mechanic." I don't have time left to know all that you know. And I do understand how those who believe they are at the top of their field can be very touchy and easily provoked with others who are not up their standard.

Not a mechanic. I am a welder, steel fabricator, power engineer, and a denturist. I have spent a life time of learning and listening to genius and idiots. A smart person learns more from an idiot than an idiot learns from a genius. I am not a genius. I just actually listen to what everyone says and learn from each interaction.

You came on here and asked a question that in theory made sense but is practically dumb. You have been told that by many smart people that it was not a good idea and were given many better ideas. You then had 2 choices. Be a visionary and peruse your solution and prove us all wrong or implement one of the suggestions. You instead chose to whine about the fact that no one felt your proposed idea wasnt a good one. The ignorance to the subject isnt the issue, its the whining and unwillingness to pay attention to what is right in front of you that is annoying.

 

[snoobler]

Locking thread.

Has degenerated into a completely unconstructive series of personal comments against other members.

OP: answer your own question. Run you car for a set period of time and measure the amount of fuel burned.