Is it your alternator or battery? When your car refuses to start, most people immediately blame the battery. But here’s the catch—sometimes the battery isn’t the villain. In many cases, the real issue lies with another critical component: the alternator. Knowing which one’s at fault can save you time, money, and a whole lot of frustration.

At Deltec Batteries, we’ve seen this scenario countless times. That’s why we don’t just replace your battery and send you on your way—we find the root of the problem.

Alternator or Battery —Which One is to Blame?

Your car battery has one primary job: to supply the power needed to start your vehicle. Once the engine is running, the alternator takes over—supplying electricity to all electrical components and keeping the battery charged.

Because they work so closely together, symptoms of failure can look nearly identical. Slow starts, dim lights, and warning messages on your dashboard can be caused by either component. That’s why a proper diagnosis is key before replacing parts unnecessarily.

Common Signs of a Failing Alternator

While alternator and battery issues can overlap, certain symptoms often point to alternator trouble:

• Dashboard warning light (usually shaped like a battery or says “ALT/GEN”)
• Flickering or overly bright headlights that change as engine speed changes
• Electrical accessories cutting out (A/C, wipers, infotainment system)
• Burning smell (overheated wiring or slipping alternator belt)
• Growling or whining noises from the engine bay

If you’re noticing more than one of these signs, your alternator might be struggling to keep up.

How to Diagnose the Problem

You don’t always need advanced tools to get an idea of what’s wrong.

• Visual inspection: Look for loose or damaged belts, burnt smells, or visible damage to the alternator housing.
• Voltage test: A healthy alternator should show between 13.5–14.5 volts on a multimeter while the engine is running.
• Negative terminal test: With the engine running, carefully remove the negative battery terminal. If the car stalls or performance drops, the alternator may be faulty.

(Note: Always take safety precautions—or better yet, let professionals handle these tests.)

Repair or Replace?

If your alternator is failing, you have two options:

• Replace it—but always choose a genuine replacement. Cheap knock-offs may fail faster and risk damaging your electrical system.
• Refurbish it—often a cost-effective solution. Common repairs include replacing brushes, voltage regulators, diodes, or bearings.

At Deltec Batteries, we help you choose the best option based on your budget and vehicle needs.

Why Visit Deltec Batteries?

At Deltec, we don’t guess—we test. Our technicians are trained to diagnose charging system issues accurately, so you don’t waste money replacing the wrong component.

• Professional diagnostic tools and expert staff
• Large stock of high-quality Deltec batteries
• Services for alternator and charging system issues
• Bellville and Tokai locations for easy access

We make sure you leave with a solution that lasts—not just a temporary fix.

Final Word: Don’t Wait Until You’re Stranded

If your car is showing signs of electrical trouble, don’t wait for it to leave you stuck. Visit Deltec Batteries for a professional diagnosis. Whether it’s your alternator, battery, or something else, we’ll help you bring your car’s power back to life.

Want to know how you might be damaging your car battery? Click here to read more.