Semi-hybrid XJ?

[Wow]

if you're so convinced it'll work, why are you sitting here arguing for 2 pages with people that are telling you that it mostly likely wouldn't be worth it???

I wasn't looking for anyone's permission. I was hoping someone would have some real numbers as to the power and fuel consumption of the engine accessories. What I got are a bunch of people who totally don't get it or are making random guesses.

 

[MaXJohnson]

miles driven per year = 12,000
fuel mileage in MPG = 17.0
typical cost/gallon = $2.75

annual cost for fuel = 12,000 / 17.0 * 2.75 = $1941.18 per year

cost of fuel for 5 years = $ 9,705.88

This is likely to increase as the cost of fuel over the next 5 years will easily exceed $2.75/gallon

Just to break even at your modification cost estimate of $500.00, your mods will need to save 5% in fuel efficiency. I think it would cost more the $500.00 to do a decent job.

At steady state cruise, say 60 MPH, 15% of the drag on a typical passenger car is from driveline drag. You would have to assume that 1/3 of this driveline drag is from your target accessories in order to save 5% in fuel efficiency. So in a perfect world where this is true and gas stays at $ 2.75 and your estimate of $500.00 to do the mods is reasonable, you might break even.

not likely

 

[FoMoCo]

even with 2 deep cells I think all the electric motors/pumps etc will still drain the batts pretty quickly, and with the alt switched on it would pull more hp then stock components would. why not just replace the parts that need replacing then get an underdrive pulley kit, way more bang for the buck IMO and far simpler

 

[jeepcomj]

I say do it. you'll have fun.

but it's not going to save you moeny, it's not going to be more fuel efficient, and you're tinkering with simple designs in favour of more complex systems. end result, more specialty parts needed, more repairs WILL be needed (at least at first...while you're figuring the whoel thing out), repair cost will be higher, you won't be able to take it in to have any of that system serviced (you apparently know how to do that anyways), and it's gonna be a bitch in general.

with someone so concerned over fuel mileage and efficiency and horsepower, WHY don't you just remove the damned a/c?

I went the simple route...bought an 86 4 cyl cherokee as a DD. 5 speed. I'm getting 19mpg highway, and 22 city (30" tires and 4.10 gears). I'm happy with that, it's of less value than my 86 comanche.


anyways, it boils down to what you can do, while making it work, and making it cost-effective. I say go ahead, ignore all of us who say it's going to be a waste of time, and build the sucker.

or just go full electric.

 

[Wow]

it's not going to be more fuel efficient

That's just plain wrong. It WILL save gas, the question is how much. There are tons of people who convert to just an electric fan for the fuel savings and claim as much as 5%.

with someone so concerned over fuel mileage and efficiency and horsepower, WHY don't you just remove the damned a/c?

The difference in gas mileage between using the A/C or having the windows down and increasing drag is a wash. Plus I only use it for 2 months out of the year.

 

[MaXJohnson]

That's just plain wrong. It WILL save gas, the question is how much. There are tons of people who convert to just an electric fan for the fuel savings and claim as much as 5%.

yeh, I claim 50%

The difference in gas mileage between using the A/C or having the windows down and increasing drag is a wash. Plus I only use it for 2 months out of the year.

2 months a year? what about defrost?

Your concept is sound, witness the current trend towards electric assist steering and the almost total takeover of electric fans. The Prius has both electric steering and air conditioning(yes, I know it's out of necessity).

The problem is trying to do a one-off engineering replacement of existing systems. The payback just isn't reasonable. As the cost of fuel increases, this will change.

 

[jeepcomj]

defrost isn't tied into the a/c. that's just a setting in the heaterbox and uses only the electric fan.

your thoughts on the a/c issue is sound.

the power steering...will be sound, but expensive to replace.

I don't like your idea on the alternator switch-off, because it will still generate power, just not have anywhere to put it.

likewise with the power water pump, I think it will be an issue and wouldn't do it (a new mechanical pump is cheap anyways)

 

[Ecomike]

Defrost does use the A/C. The air is cooled first, condensing out water vapor, then reheated with the heater core. This allows dryer air at ambient or higher temperatures to be returned to the windshield to dry condensation off the inside of the windshield in high humidity climates while also defrosting the outside, if needed. The need for it varies with the climate and humidity.

The alternator does not generator power, or consume significant HP when the output wiring is an open circuit (switch Off). It does use HP proportional to the current drawn feeding into the battery to recharge it.

Part of the problem here is many of these loads being discussed are not constant, for instance the power steering and alternator are variable loads on the engine and vary by as much as 1000% from peak load to minimum load.

defrost isn't tied into the a/c. that's just a setting in the heaterbox and uses only the electric fan.

your thoughts on the a/c issue is sound.

the power steering...will be sound, but expensive to replace.

I don't like your idea on the alternator switch-off, because it will still generate power, just not have anywhere to put it.

likewise with the power water pump, I think it will be an issue and wouldn't do it (a new mechanical pump is cheap anyways)

 

[DirtyMJ]

Part of the problem here is many of these loads being discussed are not constant, for instance the power steering and alternator are variable loads on the engine and vary by as much as 1000% from peak load to minimum load.

Exactly!

With my propane 4.0, it'll idle all day at 250rpm. But if you turn the steering wheel at that speed the load from the pump will stall the motor out. Likewise, if I power up the fans for the radiator, the rpms will drop and the engine will labor more or sometimes even stall.

 

[jeepcomj]

uh...YEAH RIGHT on the defrost. my non-air conditioned comanche has defrost. all of them have actually.

so no, you do not need a/c for defrost to function

 

[Dave41079]

uh...YEAH RIGHT on the defrost. my non-air conditioned comanche has defrost. all of them have actually.

so no, you do not need a/c for defrost to function

No one said you need AC for the defrost to function. It will function without it. What they are saying is that if you DO have AC, that the compressor kicks on when defrost is activated. Go find someone with AC and get the to turn the defrost on and you'll see.

 

[TRAILREADYXJ]

No one said you need AC for the defrost to function. It will function without it. What they are saying is that if you DO have AC, that the compressor kicks on when defrost is activated. Go find someone with AC and get the to turn the defrost on and you'll see.

Yes, you don't need the compressor to run, but it does turn on in Defrost. As mentioned, it turns on to clear condensation from the air to clear the windows faster, but I couldn't tell much difference with or without it.
At one point, before I converted my AC to OBA, I wired in a rocker switch to deactivate the compressor during "winter" use. I tested the switch, and the compressor is only off in the vent and heat positions.


As far as converting to electric accessories, it's an interesting idea, and if you have the time and money to try it, go for it! Just don't expect something magical to happen. Be prepared to waste a lot of time and money IF it doesn't really work out for ya. I'm not necessarily trying to talk you out of anything, and be sure to post your findings! To me it does sound like more trouble than it's worth, but experimentation can lead to innovation!

Oh, It would also be a good idea to wire in cut off switches for any water crossings.

 

[ratman572]

Don't get me wrong, -I really enjoy reading threads like this, -because they get everyone thinking.

BUT, the reality is, there is no such thing as a free lunch. To begin with, the 4.0L is not on par with other engines in terms of efficiency and fuel economy, -so you already have a lot working against you in terms of economy.

The idea of converting accessories to electric (while not impossible to do) would simply take way too long to see a return on investment.

If you're serious about making the thing green, -how about a small 3 or 4 cylinder turbodiesel?? That would be pretty dang cool if you ask me.

I like the propane conversions on the 4.0's, -that's definitely a cool way to go too.

(All just my opinions of course).

Rich.

 

[balloo93]

Just go full on conversion and don't look back :laugh:

http://www.driveev.com/jeepev/home.php

 

[rockclimber24315]

You would probobly have to run the alt. because you are converting everything to electric power, unless you have a whole bank of batts. Then your loosing HP to extra weight.

 

[fiyerbirdie]

Me thinks thar be a troll abouts. Rrrrrr

That is a good point, but it won't effect HP and MPG "significantly". A while ago when my alternator died I drove around for two months with no alternator, I just charged it when I got home. I noticed no difference in power or mileage. There probably is a slight decrease in both, but that could be fixed with an aftermarket coil. Many high power dragsters have no alt.

I believe the "high power dragsters" you speak of use a magneto. That eliminates half of the standard ignition components.

Good basic idea, stop "dreaming it" and start "doing it." Although I don't think you'll succeed exactly how you think you will. But hey, Columbus was trying to go to the Indian islands right?.... so you might figure something really unexpected out. Good luck.

 

[89xj]

wouldnt you also need to factor in the money it would take to charge the batteries every night? wouldnt you also shorten the battery life, even with a yellow top. i think you would need a different high cost battery.

 

[Ecomike]

Were not looking for a free lunch, (not that I would turn down a free steak mind ya, :clap just looking for a cheap discount lunch!

Don't get me wrong, -I really enjoy reading threads like this, -because they get everyone thinking.

BUT, the reality is, there is no such thing as a free lunch. To begin with, the 4.0L is not on par with other engines in terms of efficiency and fuel economy, -so you already have a lot working against you in terms of economy.

The idea of converting accessories to electric (while not impossible to do) would simply take way too long to see a return on investment.

If you're serious about making the thing green, -how about a small 3 or 4 cylinder turbodiesel?? That would be pretty dang cool if you ask me.

Rich.

You mean like my SD22 Nissan Diesel 4 banger in my 85 Jeep?

 

[Ecomike]

Just go full on conversion and don't look back :laugh:

http://www.driveev.com/jeepev/home.php

Now that's a Cool, I mean HOT jeep conversion. I read somewhere recently that an electric dragster holds the world record for the 1/4 mile, something in the neighborhood of 1 second, OUCH!

Now all he needs is a fuel cell for flex fuel to charge those batteries, LOL.

 

[kennzz05]

how bout a windmill on the roof to charge the batterys make it out of the alternator