Help! My Battery Won’t Hold A Charge!
February 18th, 2016
At St. Lucie Battery & Tire in West Palm Beach, FL and Jensen Beach, FL, we run across a lot of customers who come in with a battery that apparently won’t hold a charge anymore. This is something that seems easy, but it can get complicated pretty quickly. Let’s do a process-of-elimination to address some of the potential causes:
- What kind of shape are the battery’s posts, cables and cable clamps in? It’s easy for a battery to build up corrosion around the clamps and posts, which will usually appear as greenish-white, fluffy deposits. In extreme cases, it can even look like a glassy substance on the post itself. Either way, corrosion will prevent the battery from getting a good charge from the charging system, or can be enough to prevent it from delivering enough voltage to the starter. Corrosion can be cleaned with a stiff wire brush, and then an application of dielectric grease or even Vaseline can prevent it from forming again.
- If the battery is a “wet” design, with access to the individual cells and not a sealed “maintenance free” style, is there enough fluid in the cells? Remember to top off the cells with distilled water only.
- How old is the battery? Like the battery in a cell phone, a laptop or any other rechargeable battery, a car battery can only withstand a certain number of charge/discharge cycles before its storage power starts to weaken. Even the best automotive batteries are only good for a five or six-year service life, under the best conditions. In places with temperature extremes, such as Texas or New Mexico, a battery might only last for three years. Cold weather, while not a big concern in Jensen Beach FL or West Palm Beach, FL, can also stress a battery. At 20 degrees F, a battery can only deliver 50 percent of its cranking power!
- A weak battery can also be due to a poorly-performing charging system, and more often than not, a failing alternator is the culprit. An alternator can be overloaded by something like an aftermarket sound system, causing it to overheat and fail, and a failing alternator can’t charge the battery properly. Dim headlights are a sure sign of a charging system problem, not necessarily a battery issue. Many parts stores have a test stand where the alternator can be checked; if it’s necessary to replace the alternator, make sure it has the same or higher amperage as the original-equipment battery specifications.
- Another charging system problem can be the voltage regulator. The voltage regulator prevents the alternator from overcharging the battery; many vehicles have the regulator built into the alternator or incorporated into the powertrain computer’s functions. Still, some older vehicles might feature an externally-mounted regulator, which can fail and cause charging problems.
- Something could be discharging the battery while the car is parked and the key is out. It’s normal for things like the clock, the digital radio and various computer functions to draw a small amount of current from the battery while the engine is off. Their chips have stored information and settings that rely on that small current draw to preserve their memory. Other are on a timer and go to sleep or standby mode…but on occasion, one of those systems can continue to draw current rather than powering down. Other possibilities include a stuck switch or relay for something like the fuel pump, keyless entry, rear window defogger, antilock brake module or others. Sometimes even a diode in the alternator can cause current to leak from the battery! An auto repair tech can connect a multimeter to the battery while the engine is off and get a reading on current draw, then begin to track down a problem from that starting point.
- If the engine cranks too slowly to start, it’s still possible that it’s not the battery. Slow cranking accompanied by unusual noises could mean a starter that’s about to fail. If the battery cables have been replaced at some point, it’s possible they aren’t the right gauge; cheapo replacement cables might have thick insulation but small-gauge wire that can’t deliver enough amperage to the starter. A click when trying to start the vehicle (but all the lights, radio, etc. are working) could mean a bad starter relay.
Our list, while far from covering every reason for poor battery performance, hopefully clears up some misconceptions about car batteries for the average driver. If you’re concerned about your battery, make an appointment and come on down to St. Lucie Battery & Tire in West Palm Beach, FL or Jensen Beach, FL and let us have a look!
Posted in: Auto Repair 101
Comments:Cheyenne Cornell says:
May 21, 2014 at 8:24 am
You guys are great!
Richard A. Rappa says:
February 20, 2016 at 7:03 pm
As a local General Contractor I can not say enough good things about the servicing and repairs that you guys have been doing for me for many years to get me in and out of your shop and quickly back to the job no matter what the task. Hats off to all of the employees at the SLT&B for your great service!
Linda Lewellen says:
May 9, 2016 at 3:06 pm
Mike, Marco, Michelle and the crew at the Jensen Beach store are the best!!!