Test: Alternator vs. no alternator = 10% MPG gain @ 70 km/h

[Philscar]

Here's a silly idea.Take an old turbocharger,use it to drive an alternator then install it in the exhaust system for free electricity.
Most of the energy from gas goes out the tailpipe.

Phil

[MetroMPG]

Phil: Google "TIGERS exhaust generator".

Nerys: sure you could. But it would be much simpler to just stop the engine (thus the alternator) before you electrically dis/connect it.

[RJVLER]

There would be no benifit from turning it with the rear tire or air. Work is work. But it would be interesting to drive it with the turbulant air that has to enter the car for cooling. Would be quite a job but interesting thought. What do you think about wiring your relay in with the brake light circuit so it comes on automatically when you have to brake

[RJVLER]

There would be no bennifit from turning it with the rear tire or air . Work is work. But that being said you already have turbulant air that has to enter the car for cooling. It would be a big job but dont know if that would work either. What about wiringyour relay also into the break light curcuit so it will come on automatically if you have to break ?

[selene]

There is one mod in an Eagle Research book, that cut off alternator load when engine load go through a set threshold. I don't know where I put these damns books. I think i lent them to my mechanic ... in France -_-' .

[darlo]

I am seriously considering deleting my alternator, after reading through this topic! If I go with 4 12V 750CCA deep cycle batteries (costco), would they last longer than if I simply went with one or two? What I mean is, is 1/2 killing one battery worse than 1/8th killing 4?

If I buy 4 @ $80 = $320 and they last 2 years, that is $13.33 per month.

If I buy 1 @ $80 = $80 and it lasts me only 3 months..... = $26.67 per month.

I know I would be sacrificing some rolling resistance due to the weight, but if it is better in the long term........

I wont have an issue with the water pump.....I can find another belt for that for $10 or so.....

[roflwaffle]

I really doubt you're going to kill a 5+ kWh battery in three months. Assuming you drive 10000 miles/year at 30mph, and your car uses 200W on average, then you'll put the equivalent of ~15 100% dod cycles on it, which shouldn't kill any deep cycle battery. You should fill in the specifics to get a better idea of the wear on your battery, but I really doubt you'll need more than one deep cycle battery unless you are driving more than 5 hours w/o charging and have fairly high current draws (~500W).

[darlo]

Originally Posted by roflwaffle

I really doubt you're going to kill a 5+ kWh battery in three months. Assuming you drive 10000 miles/year at 30mph, and your car uses 200W on average, then you'll put the equivalent of ~15 100% dod cycles on it, which shouldn't kill any deep cycle battery. You should fill in the specifics to get a better idea of the wear on your battery, but I really doubt you'll need more than one deep cycle battery unless you are driving more than 5 hours w/o charging and have fairly high current draws (~500W).

I drive around 600 Miles a week on average (less in the summer), but since June 2010, I have gone 15000 miles. Also, my stock alternator is only 50 amps, so that is in my favor! I basically want to make sure I could drive for 4-5 hours @ 50 mph and not have to even think about worrying about running out, lol!

My question was also about what is better for the life of the battery too, and what would be harder on the car?

Is there any other things to watch out for when doing this mod? I am not very mechanically inclined, so I may be thinking this is easier than it sounds?

I am literally thinking of just buying a couple big deep-cycles, hooking them up to my existing starter battery, and then removing my alt belt and installing a shorter one that just hits my engine and water pump. Oh and I was thinking of perm installing a battery charger so I would simply have to plug my car in at night!

Will this work, and is it that simple?

[roflwaffle]

Scratch what I said earlier about the energy per battery, since it's closer to 1300Wh than 5000Wh.

Before you get any batteries you should probably measure the power draw of your car like MetroMPG did assuming a high use scenario like having the high beams on, the heater fan on high, the defroster on, the radio on, the wipers on, and whatever else you think could likely be on.

If it's 500W, and you want to drive for five hours, then you'll need at least 2500 Wh (500W*5h), which would require 2 of the 115ah Kirkland batteries at least, depending on whether the Kirkland battery is rated for 5 hours or 20 hours. If Kirkland is listing the 20hr rate, then you'll only get about half ([url=http://www.csgnetwork.com/batterylifecalc.html]Here's a calculator for battery energy versus discharge rate), maybe less, of the ah rating if you're using the battery at a 5hr rate, so you would need at least four of those batteries for a 5h trip at 500W.

Since you want to be on the safe side, you would probably want 3 to 6 batteries, depending on whether or not the Kirkland ah rating is for 5h or 20h, at least for 5h of driving at 500W. If I were you I'd start out with an alternator kill switch, one Kirkland battery, your starter battery in the trunk, and the right wrenches to swap it back in, since that'll allow you to see how much mileage you gain and how far you can go on one Kirkland battery. If you run out of juice, just swap in your old battery. If you find that the mileage increase isn't worth it then you can just return the Kirkland battery, and if it isn't worth it you can get however many Kirkland batteries you want and wire them up in parallel along with a cord to plug a battery charger into.

[darlo]

How do I go about figuring out how much draw I have???

I think I will go with 3 of those deep cycles from costco. What guage of wire would I need to run for these? Is 8 guage big enough?