Your vehicle’s battery and charging system are essential to modern driving. The SLI (starting, lighting, and ignition) battery provides initial power to the starter motor, ignition system, fuel system, and engine management computers. Once the engine is running on its own, the charging system takes over, generating current to recharge the battery and power the vehicle’s lights, audio, climate control, navigation, and other systems. Here’s how to maintain your car’s battery and charging system for reliable performance, no matter the weather!
Limit corrosion – Ohm’s law states that, for a given voltage, electric current (amps) decreases as resistance (ohms) increases. The average starter motor draws up to 250 amps, but corrosion creates resistance, reducing the flow of current through the circuit. Crusty or fluffy blue, green, or white corrosion on the battery terminals is one of the more obvious signs, but some corrosion is hidden, such as inside battery cables. Clean visible corrosion and coat with dielectric grease to protect it from oxidation. A voltage drop test can indicate hidden corrosion. Fortunately, replacement battery cables are available for most applications.
Minimize unnecessary current draw – A car battery is designed to use a large amount of current for only a few seconds, just long enough to get the engine started so the charging system can power the rest of the vehicle. Excessive draw, such as from listening to the radio without the engine running or leaving lights on overnight, can permanently damage the battery, preventing it from fully recharging. Make sure all your accessories are off when shutting down your vehicle. Recurring problems may indicate a faulty circuit or module. A parasitic drain test—look for draw in excess of 50 mA—can help you isolate and fix the issue.
Check your drive belt – The alternator generates electricity to power the rest of the vehicle. A worn, loose, or slipping drive belt may not reliably drive the alternator if it’s wet or under high load conditions. Inspect the drive belt for wear or contamination, and to ensure proper tension. Replace a worn or contaminated drive belt. Replace the drive belt tensioner if the spring is worn.
Clean your engine – Maintaining a clean engine isn’t all about appearances. Oil leaks, such as from valve covers, oil seals, or hydraulic power steering systems, can cause many problems that won’t show up immediately. For example, a leak can contaminate the drive belt, causing slipping and a lower alternator output. Oil leaking on the alternator or starter can cause overheating and burn out the windings. Fix oil leaks as soon as they’re noticed. Clean the engine regularly to prevent contamination of sensitive starting and charging system components, but don’t spray cleaners directly into the alternator or starter. Overspray is fine.
Drive regularly – As your car battery drains over time due to parasitic draw and self-discharge, it’s important to regularly top off the charge. For most vehicles, regular driving—at least 20 minutes every few days—is enough to keep the battery charge at an ideal level. That’s why daily drivers hardly ever have starting problems. Vehicles that aren’t driven often might benefit from a battery float charger, which keeps the battery at an optimal level to prevent permanent damage. Drive regularly or install a float charger.
Fortunately, your car’s battery and charging system don’t require much maintenance. However, this doesn’t mean you should put them out of your mind until they cause car starting problems. Furthermore, if your vehicle won’t start, the issue isn’t always related to your battery or charging system. You may need a digital multimeter (DMM) or scan tool to get more in-depth information about your vehicle. Next time, we’ll look at how to choose automotive diagnostic tools.
By Benjamin Jerew