As a fleet manager, there’s something strangely unsettling yet completely normal about that unmistakable sound of a car struggling to start. When that sound happens, the battery is usually the first thing you think of.
But before it gets to that point, there are usually a few telltale signs that a battery is heading for trouble. When your drivers are trained to recognise early symptoms and report them clearly, your technicians can intervene before it results in downtime. That saves your fleet time, money, and plenty of frustration.
The obvious: problems with starting
At first, it might be nothing more than a slow crank. The engine turns over, but it takes longer than usual. Then it reaches the point that you need to turn the key and crank the engine two or three times before it fires up. Those are some sure signs that the battery’s struggling in some capacity.
When you hear that grating, quick clicking sound, or even that single ‘click’, it might sound like a faulty starter motor, but it’s often a weak battery. A weak battery can’t provide the cold cranking amps needed, so the solenoid clicks but doesn’t engage the starter.
Sometimes, a jump start will get the vehicle moving again. But in a fleet environment, where reliability is the name of the game, it’s still good practice to carry out a battery test. Occasionally, it’ll flag an underlying problem that might prevent the vehicle from starting again mid-route.
Electrical system problems
The vehicle might start, but that doesn’t mean the battery’s in the clear. Look to the electrical system. If you notice headlights dimming or interior lights fading, it’s a sign the battery isn’t holding charge as it should.
Then, there are the other accessories to take note of. The radio cuts out, or the air conditioning fans flicker. Inconsistent electric windows or wipers are another red flag. Sometimes, you’ll trace these back to a power supply problem caused by a battery that’s nearing the end of its service life.
Modern vehicles have on-board diagnostic systems (OBD II) that give a clearer picture of the battery’s health. As you know, a warning light or a dashboard notification about the battery should never be ignored. Reading these codes quickly can help you confirm if the battery is the culprit before making costly repairs.
If your vehicle diagnostic tools show irregular voltage fluctuations, it’s often a sign of an aging or faulty battery.
The physical signs of a poor battery
Sometimes, a quick inspection under the bonnet tells you everything you need to know.
Start with the battery terminals. If you see corrosion, it could indicate a deeper problem. Corrosion typically results from battery gassing (often due to overcharging or aging cells) leading to acidic build-up on the terminals. If you spot corrosion around the terminals, clean them off with a battery cleaning solution before you proceed with further tests.
Next, look for any physical damage to the battery casing. If it’s swollen, cracked or deformed, it’s a sure sign that the battery has been overcharged or overheated. Batteries work best in specific temperature ranges. If they’re pushed beyond those limits, they fail much quicker.
Even more concerning is the presence of any electrolyte leakage. If you see any fluid around the battery, it’s leaking and unsafe to use. Leaking batteries can lead to electrical damage or even more dangerous scenarios. It’s time to replace the battery and dispose of the old one properly.
Regular inspections and battery checks will help you stay ahead of these issues.
Use, age and the environment
Batteries don’t last forever. For fleet vehicles, the three-to-five-year benchmark remains, but use patterns can significantly alter that estimate. Short trips, stop-start routes or prolonged idling (common in last-mile delivery or utility service fleets) often mean the alternator isn’t given enough opportunity to fully recharge the battery.
Age is also important. A battery might look okay, but after a few years, it can’t hold a charge as effectively. Even if the vehicle hasn’t been driven much, battery capacity still declines over time due to natural chemical aging.
Seasonal changes make things worse. Batteries don’t like the cold, and the cold doesn’t like them. During winter, a battery’s charge capacity drops, and the battery is under more strain trying to start the engine because the oil is thicker. On the flip side, hot weather causes batteries to overheat and degrade faster. In a fleet, where your vehicles may operate across different regions and climates, the impact of temperature on battery health is something to stay on top of.
Proactive battery management prevents breakdowns, saves time and money
We all know the cost of a roadside breakdown. It’s not just inconvenient for your customers; it’s a headache for your workshop, too. Proactive battery management can save you and your customers from dealing with emergencies. A good, proactive maintenance schedule can extend the life of the battery by catching small issues early and preventing them from becoming costly repairs.
The more your team understands what early signs to look out for, the fewer surprises you’ll face on the road.
Most importantly, make sure your equipment is up to date and ready for quick diagnostic checks. Rotronics’ range of battery maintenance tools supports testing across 12-volt and 24-volt systems. Built with fleet technicians in mind, these devices keep your vehicles working longer without unnecessary breakdowns. Simply hook up your battery tester and read the results.
If your organisation could use a helping hand with battery maintenance, Rotronics is here. We specialise in the equipment you need to keep your fleet or garage operating smoothly. Get in touch today for a commitment-free chat about your needs and how we can help.
