The most frequent causes are electrical issues, constant running, and faulty parts. One popular cause involves a faulty fuel pump relay. Sometimes it cannot shut the fuel pump off in case the car is not running. If the relay jammed into an “on” position, the pump continued drawing power from the battery until it got completely discharged. For example, mechanics say a fuel pump that has been left on overnight can completely drain a battery, especially if it is old or weak to begin with.
Other factors that can also contribute to battery drain include an aging or failing fuel pump, since it requires more power in order for it to work correctly. With internal parts wearing down, the pump requests more current as a way of maintaining pressure inside the fuel; hence, it puts extra load on the battery. For instance, a worn fuel pump drawing 20% more than normal current greatly reduces battery life since the alternator cannot get sufficient time on short trips to recharge the battery.
Second, faulty wiring or poor electrical connections can be another easy culprit to drain batteries in fuel pumps. Resistance is created when wires are loose or corroded, forcing the fuel pump to pull more power than what is generally required for proper functioning. This increased demand for current depletes the battery, especially when the vehicle is parked for an extended period. Regularly checking wiring and connections to make sure they are secure and free from corrosion helps avoid this.
The main problem with an alternator is that, while it might consume some power of its own, it tends to make battery drain from the fuel pump worse. In such cases, when this alternator operates below capacity, the battery frequently steps in and supplies the vital parts, possibly including a fuel pump. This additional burden on the battery will, of course, result in faster wear on the battery, particularly if the alternator output falls below the typical 13.5 volts necessary for maintaining equilibrium in the electrical system.
Why do fuel pumps drain batteries? These include malfunctioned relays, aging components, bad wiring, and alternator failures-all contributing to high power draw. All of these factors need regular maintenance, and the components should be checked to keep the battery’s life and allow for continuous operation of the fuel pumps.