How to minimize electrical power consumption of a car

How to minimize electrical power consumption of a car

It is often desirable to minimize electrical current draw of the different electrical loads of a car. This minimizes stress on components like Alternator, Battery and Electrical cables. This in turn prolongs the life of those components.

Some people are actually doing non-standard practices that causes higher current draw than modifications that are benefitial.

  1. Ensure that battery terminals are tightened. When the point of electrical cable connection with the battery is not tight, it forms a point of high resistance to current and at that point, the electrical current would be converted to heat, thereby increasing power consumption.
  2. Replace old and degraded cables. Example is the cable that runs from alternator to the battery. When this cable is old and has developed more resistance that is out of specification, it is going to cause voltage drop. This is because there would be significant current draw by the cable itself. Recall that P = I^2 * R, V = I * R
  3. Keep cooling fan connection stock. The cooling fan is designed to kick into operation only when the engine has attained a certain predetermined temperature. Again, the fan is not meant to keep spinning continuously without stop or speed reduction. For some reasons, such as masking of overheating or not getting to properly diagnose an electrical fan circuit fault, some people connect the fan to a direct battery or alternator voltage point. This makes the fan to operate at full speed, drawing maximum current that it can draw.
  4. Use Light Emitting Diode (LED) bulbs. Light Emitting Diode bulbs have low power consumption compared to incandescent light bulbs. Even if all the lights cannot be retrofitted, it might be easy to retrofit interior lighting, fog lights , trunk lights and number plate lights.
  5. Keyless entry cars should be locked when there are no occupants in the car. This is because when the car is in an unlocked state, more electronics that control signal reception from the key and other electronics that controls some other accessories are active. This does not only occur in a keyless entry car though but the current draw in keyless entry cars are higher. A test was one on a 2006 volkswagen passat Vr6 and the current draw when the car was unlocked was about 10 amps while the current draw while the car was locked was less than 0.5 amps. That's a huge difference. Imagine how the battery will quickly drain when this car is left unlocked even though it is equipped with a 100 Ah capacity battery.
  6. Electrical connections and earthing points should have good contact. This is because electrical resistance can be created at these points, creating voltage drops and even adding to the electrical power consumption.
  7. Have a good and strong battery. When batteries go weak, they exhibit a particular behavior - they take a lot of current to charge, they might even take a longer time to charge and them discharge over a short period of time. A good battery will go through a phase of boost charge and then float charge but a bad battery might keep drawing current continously.
  8. For Hybrid vehicles, hybrid batteries should be in good condition as weak batteries draw excessive current and tend to heat up easily. When they get heated up, this causes the battery cooling fan to activate more frequently, thereby consuming more electrical power.

Minimizing power consumption can in turn lead to lower fuel consumption thereby lowering fueling cost. The impact on fueling cost is small over a short period but it is is appreciable over long periods of time. Again, practices that make one to minimize electrical power consumption also help in giving the car a good maintenance that can prolong the life of parts in the car and the car itself.