Why car battery keeps dying but alternator is good can leave many drivers in a frustrating bind. However, this phenomenon is quite common and has several underlying causes.
This article will discuss the reasons why a car’s battery will die even though it has a good alternator. Also, we’ll discover practical methods that you can take to rectify the situation should you find yourself in this situation.
- 1 Why Does the Car Battery Keep Dying but Alternator Is Good?
- 1.1 – Forgetting to Switch off Headlights and Dome Lights
- 1.2 – Car Batteries That Lose Their Potency Overtime
- 1.3 – Batteries Affected By Extreme Weather Conditions
- 1.4 – Loose Battery Connection to the Alternator
- 1.5 – Defective Car Battery Charging System
- 1.6 – Corroded Terminals of a Car Battery
- 1.7 – Parasitic Drains Reducing Battery Power
- 1.8 – Taking Too Many Short Journeys
- 1.9 – Starter Draining Your Battery
- 2 What Are Solutions to Car Battery Dying but Alternator Is Good?
- 3 Conclusion
Why Does the Car Battery Keep Dying but Alternator Is Good?
A car battery will keep dying but the alternator is good due to leaving the headlights on overnight, weak batteries, and extreme weather conditions. Loose battery connections and challenges with the battery charging system can also cause the battery to die even though the alternator is good.
– Forgetting to Switch off Headlights and Dome Lights
Headlights consume a lot of energy from the battery and can drain it when left overnight. The dome lights illuminating the car’s interior can also have the same effect on the vehicle if you forget to switch them off.
Batteries work even when the engine is off and they have a very limited capacity, which drains much quicker. Thus, buying lunch across the street or talking with a friend while the headlights are still on can cause a drained battery.
– Car Batteries That Lose Their Potency Overtime
Car batteries, just like any other component, get weak over time and lose their ability to produce enough power. This process is often fast-tracked by poor battery maintenance and improper handling.
Also, when too much stress is placed on the battery, it is overworked, or it is used to accomplish tasks that are beyond its capacity, it becomes weaker. Weak batteries won’t function properly and would drain quickly regardless of how long they are charged.
– Batteries Affected By Extreme Weather Conditions
Extreme temperatures can also take a toll on the health and lifespan of a car battery. An extremely high temperature can cause premature aging of the battery and untimely battery failure. Also, it causes a faster chemical reaction between the chemicals of the battery, which increases water evaporation. Also, the hot temperatures can increase the rate of corrosion by speeding up self-discharge and corroding the plates, resulting in a weaker battery.
Extremely low temperatures also have negative effects on the strength of a car battery. When the weather is extremely cold, it may slow down the chemical reactions of the liquids in the battery, resulting in a weak battery. Also, the extremely low temperature increases the resistance in the battery, which means that it’ll take longer for it to charge. This affects the capacity of the battery and shortens its lifespan, leading to a car that won’t start.
– Loose Battery Connection to the Alternator
A slack battery connection to the alternator can affect how the battery is charged. In most cases, the battery will be undercharged as the loose connection supplies low power to the battery. Sometimes, sloppy connections can build resistance in the battery, which may affect the charging system and car electronics.
A loose battery terminal can also cause a slow cranking noise or a rapid clicking sound, which can be very unsettling.
– Defective Car Battery Charging System
Just as with the other problems above, a faulty charging system won’t supply enough energy to the battery to help it function optimally. This may be attributed to a broken or worn-out alternator belt or one that easily slips and falls off.
If the alternator belt is faulty, the voltage required to charge the battery drops, which may give the impression that the battery wasn’t charged. Also, an old battery won’t be able to hold a charge and thus not perform as expected even though the alternator is in healthy condition.
– Corroded Terminals of a Car Battery
Battery corrosion is normal and occurs when the hydrogen gas from the chemicals in the battery escape and reacts with moisture and salt in the air. It usually occurs around the terminals of the battery, thus preventing the battery from receiving the full power it requires to charge properly. This reduces the battery’s lifespan as it fails to operate at full capacity, putting excessive strain on the dying battery to run the other car electronics.
– Parasitic Drains Reducing Battery Power
Parasitic drains, also known as parasitic draws, are electrical systems that run in the background even though your car’s engine is off. These devices usually don’t require your input and most of the time, you won’t be aware of their activities, which is why they’re called parasites. Their activities seem innocuous but can cause battery drain if they are not regulated.
Common parasitic devices include the glove box and trunk lights, which can turn on and stay on for long periods.
– Taking Too Many Short Journeys
Though this may seem unlikely, taking too many short trips can negatively impact the battery’s health. It takes a lot of power to start a car (150A – 350A), which can cause battery drain if you start and stop the car too many times.
This is because the alternator won’t be able to replace the lost charge in time, which will affect the battery’s health. Sometimes, short trips are unavoidable, especially in urban areas, which is why you may be experiencing a dying car battery.
– Starter Draining Your Battery
The signs of a starter draining your car battery include strange noises, smoke, unusual smell, engine refusal to turn and when the starter is soaked in oil. Fixing or replacing a car starter can only be done at auto shops due to the technicalities involved.
What Are Solutions to Car Battery Dying but Alternator Is Good?
The solutions to car battery dying but the alternator is good include switching off the headlights, dome lights, and parasitic devices of your car. You can also fix the corroded terminals of the battery, repair the charging system, avoid taking too many short trips, and fix loose connections.
For those who are worried, a car battery doesn’t die when you don’t drive it for three days because it is still being used by other components. Generally, a car can sit for about a month or two before the car battery runs out. Thus, a car battery dead after sitting 5 days is highly unlikely.
All is not lost when your battery keeps dying even though the alternator is healthy. In most cases, you can fix the issue and the battery will return to its healthy state. Some solutions will even require you to change how you drive and that’ll be all. Here are a few ways to solve issues related to bad batteries:
– Switch off Headlights, Dome Lights, and Parasitic Devices
Whenever you disembark from your car, remember to switch off your headlights and dome lights even if you’re just going to get coffee across the street. These lights consume a lot of energy when you turn them on, thus avoid doing that frequently. When they are on, make sure they stay on as long as you need them, after which you can put them off. One way to help you remember to turn them off in the evening is to park in the dark, which will help you see them.
Some new cars come with a feature that switches off the lights 30 minutes after removing the key from the ignition. However, we’ll advise you to cross-check because you never know when the feature might malfunction. Also, ensure you check your car thoroughly for parasitic components that are small but can cause battery draining over time. Finding them without help is difficult, time-consuming and ultimately fruitless.
Therefore we suggest you use tools such as a multimeter, a wrench, a fuse puller and zip ties to help you out. Make sure you disconnect the negative terminal and check the current in the car with a multimeter. Monitor the multimeter while you remove and replace the various fuses one after the other to determine which ones are the culprit. Fuses that produce more than 4A could be faulty and should be replaced.
– Fix the Corroded Terminals of a Car Battery
To fix this issue, check the surroundings of the battery for any leaks and if you find one in the tray or around the bolts, then the situation is worse than it seems. If there are no leaks, then mix some baking soda with water, dip a piece of cloth into it, and use it to clean the terminals.
Remember to disconnect the battery and wear protective clothing including a pair of goggles to be safe. Once you’re done scrubbing the corrosion off the terminals, spray them with WD40 oil to polish them.
Now, thoroughly clean the top of the battery with water and wipe it with a clean rag. However, if the corrosion is severe, then no amount of cleaning or scrubbing will suffice. The only reasonable thing you can do is to purchase a new battery to replace the old one. To keep your battery from corrosion, make use of felt battery washers and protective grease.
– Repair a Faulty Car Battery Charging System
One of the ways to fix a broken charging system is to inspect the fuses and replace any of them that are blown or malfunctioning. Check the terminals for corrosion and clean or replace them accordingly.
Also, another culprit could be a bad alternator belt, which might be hindering the alternator from generating enough energy to charge the battery. An aged battery might also be the reason why the battery is not charging, therefore, inspect it as well.
– Avoid Taking Too Many Short Trips and Fix Loose Connections
One practical way to avoid taking too many short trips is to plan your trips and stick to them. If the grocery store, laundry mart and coffee shop are on the same lane, plan to buy everything you need so you won’t have to take multiple trips to the same area in a day. You can also use a bicycle for your rounds in the city if the shops and your house are not too far apart.
Also, you can check the battery for any loose wires or connections and fix them. Ensure you replace all blown fuses in the charging system so the battery can get enough power during charging. Remember to replace worn-out or torn wires and tighten loose battery cables as well.
A car can die even though the alternator is good because there are other factors and components of the vehicle that cause car battery drain.
Here is a summary of these factors and how to fix them:
- Extreme weather conditions can weaken batteries and make them run out quickly, thus avoid storing your battery or parking your car where the weather can affect it.
- Corroded battery terminals prevent the battery from getting the desired power to recharge, therefore clean the terminals with a mixture of soda water to fix them.
- You can also check the entire charging system for faulty wires and fuses hindering the charge and replace them to ensure a smooth charging process.
- Make sure you turn off the headlights and dome lights to avoid the situation where the car battery keeps draining overnight.
- Avoid taking too many short trips within a brief period because it takes a lot of power to start a vehicle, which can take a toll on the battery.
Don’t forget to check the serpentine belt as well because a defective alternator belt can hamper the recharging process. If all these measures fail, then your battery is probably too old or too weak and needs a replacement.
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