How does a car's loads affect it's fuel consumption?

AI Thread Summary
The discussion explores how various electrical loads in a car, such as LED lights, MP3 players, and air conditioning, impact fuel consumption. It highlights that while AC systems consume power, they can sometimes improve gas mileage compared to driving with windows open. The conversation includes a demonstration showing that turning on lights can slightly lower engine RPMs due to increased electrical demand, which may lead to higher fuel consumption. Additionally, older cars with dynamos experience noticeable performance drops when multiple electrical accessories are used simultaneously. Overall, the relationship between electrical load and fuel efficiency is complex and influenced by various factors.
Aicy
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Hi, so I was wondering about how the car's LED, MP3/IPOD, AC systems consumes up electrical power and then to fuel?

Let's say that the loads are running for 5-7 hours. Thanks for the replies/ideas!
 
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Aicy said:
Hi, so I was wondering about how the car's LED, MP3/IPOD, AC systems consumes up electrical power and then to fuel?

Let's say that the loads are running for 5-7 hours. Thanks for the replies/ideas!

Welcome to the PF.

What is a car's LED system?

And a car's air conditioning system (AC) power consumption is very different from any MP3/radio power consumption. Why may running the AC actually improve gas mileage?

Do you know the conversion between horsepower and watts? :smile:
 
Also, what is the context of your question? Are you wanting to have some ammunition to make your kids turn off their MP3 players on long trips? :biggrin:
 
Running the cars AC system doesn't improve gas mileage. Failing to drive with the windows open improves gas mileage.
 
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Aicy said:
Hi, so I was wondering about how the car's LED, MP3/IPOD, AC systems consumes up electrical power and then to fuel?

Let's say that the loads are running for 5-7 hours. Thanks for the replies/ideas!
Had a friend that did not believe that lights influence consumption. A simple demo.
Engine on. Lights off. Car in neutral. Look at the rpm meter. Turn on lights.
The rpm will fall slightly from the drop in electrical resistance which puts more mechanical resistance on the "alternator" and as it is connected to the engine rpms get affected. And they rise back from more fuel given to the engine by the "regulator" (no idea of the terminology in EN).
 
Any energy taken from the fuel that is not used to drive the wheels will increase fuel consumption.
Anybody ever driven an old car that has an dynamo rather than alternator? Every time you switch on something, the car gets slower...try it in the winter with the lights, heater, wipers on, any attempt to put on the radio and the car almost stops!
 
when I first read this question I thought "It depends on the terrain and how many fat ladies".
 

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