Power consumption vs. fuel economy

O dang someone ^^^^^ had to bring up the Ecotaz

 

Just my 02 cents. But, instead of blaming the bulbs. How about blaming the alternator itself. Why not build an alt. with ultra hard smooth bearings, and optimal pulley diameter. Or the fact that the belt/pulley fitment may be the cause of 90% of the drag. What would you gain by going with a wider pulley and a narrower belt. What if pulley/belt shoulder contact could be limited to under 10% instead of 100%

Once that's done, how about the tensioner and idlers. How much HP do those rob, and at what cost to fuel savings? Ever looked at the crappy block castings from a water pump. Those are begging for a balance and blueprint job. The blade itself is crude at best.

Change your math from an alternator using 40hp down to 5hp. What would the fuel savings be?

How much HP do all drive accessories consume? I would bet that power steering pump sucks some major power to keep it spinning.

 

manufactures went to serpentine belts becuase they grap better then v belts. they last longer then v belts. and they use an idler to keep the tension where as v belts require tension via the accessory they are hooked too. serpentine belts also don't stretch like v belts do.

v belts afte awhile stretch and cause whiney squeaky noises. if not kept tight.

serpentine also has the ability to run all accessorys while the v belts would require more then one belt. some alternators have two belts. specially if it also runs the a/c.

has absolutely nothing to do with fuel.

serpentine belt or v belts. your mileage stays the same. it's called technology.

the only thjing that causes a drag on the engine is the air conditioner compressor.

the alternator only causes a drag if you have dead batteries. but even that is minimal compared to what the air conditioner pulls.

and that is speaking SCIENCE.

aerodynamics and weight are the main factors for mileage. not alternators. if your that concerned. drop the trailer and just bobtail.

i get x miles per gallong with a loaded trailer. i gain 1/2 mile by being empty with a flatbed. only 1/4 mile with a tank as it's heavier. 3 miles bobtailing.

so if you want the best mileage. leave the trailer behind and bobtail. and don't run the air conditioner.

otherwise, suck it up like the rest of us do. keep your tires properly inflated. your air filters cleaned. that's all you can do. other then some expensive tweaks to the ecm and exhaust.

 

You could just microblue the alternator

 

Formula from the interweb:

Amps x Volts = Watts
Watts / 745.7 (one HP) = Electrical HP Produced by the Alternator
HP x 15% Efficiency Loss = HP Loss
HP + HP Loss = Total HP Used

So using that formula we can figure out the HP used per amp.
Example:
1A x 13.7V = 13.7 Watts
13.7 Watts / 745.7 = 0.0184 HP Produced by the Alternator
0.0184HP x 15% = 0.00276 HP loss
0.0184 + 0.00276= 0.02116 Total engine HP used per amp

Now if someone felt like testing amp draw from the truck with all accessories turned off/unplugged and again with all accessories turned on we'd know exactly how much HP is lost.

 

So now you can see that an entire whopping two hundredths of a percent of the total horsepower is used from 13.7 watts. So if you could improve on that maybe a couple of hundredths more along comes a 5 mph headwind (or some other uncontrollable real world variable) and just completely wipes out anything you've gained. It's not even a tenth of a percent loss...

 

That's per amp though. At 100 amps that'd be OVER 2 HP!!!
Or for percentage:

0.02116 / 500 = 0.004232% HP PER AMP (off a 500 HP engine)

 

like i stated earlier.

the air conditioner is where the concern would be. not the alternator.

anyone know how much horses the a/c takes away? on a car it used to be 10 % performance drop. but that was back when motors were weaker. you could literally feel the drag every time that clutch kicked in.