Battery discharge warning messages and lights mean that the car’s battery is draining more quickly than it is charging. The problem can occur when electrical accessories are left on when the engine is off. A parasitic drain can also cause this warning to appear, as can alternator issues and damage to the car battery.
How Does a Car Battery Work?
The battery is just as important to the normal function of your vehicle as its car engine. If the battery is flat, your vehicle is going nowhere! Car batteries are often made up of six cells and can produce a total of 12 volts of energy.
Most vehicles use lead-acid batteries that are made up of cells with one lead plate and one lead dioxide plate. The sulphuric acid inside the battery works as a catalyst, triggering the reaction between the two submerged plates.
This reaction produces electrons and creates the electricity needed to start the starter motor. Without a working battery, you cannot start your car’s engine – unless someone gives you a jump.
The reaction that occurs between the plates in a car battery is reversible. This means when you drive the car, the battery can be charged back up, and this is also the reason why jump starting is effective for batteries that have been drained.
The electricity created in the car battery starts the starter motor when you turn on the ignition and also powers the engine spark plugs. The spark plugs play a key role in igniting the air and fuel mix inside the combustion cylinders.
If there’s not enough charge in the battery, none of these steps can happen and you won’t be able to get your car going. Once your engine is running, the alternator takes over and supplies the car’s electrical systems with the required electrical currents.
The alternator is also the key component in keeping your car battery charged. If the alternator fails, prepare yourself for the battery to drain not long after.
Battery Discharge Warning – What Does It Mean?
If you ever notice a battery discharge warning message on your dashboard digital display, or on the infotainment system, this means that your car’s battery is draining at a quicker rate than it is charging.
The warning may be in words, or a red battery light may appear on the dashboard. Whatever the warning looks like, drivers should not choose to ignore it.
If the car battery is draining more quickly than it is charging, you are at risk of your battery going completely flat and your vehicle breaking down.
When the car battery is draining too quickly, this can cause electrical issues and lead to bigger problems with your vehicle.
Modern cars use a lot of battery power and if the battery is draining too quickly, the electrical systems and accessories will begin to malfunction.
The battery discharge warning can appear when the car is running or when the engine is off. The causes can vary depending on whether the engine is running or not, either way, you need to solve the problem as soon as possible to avoid a flat battery.
Reasons for Battery Discharge Warning When the Engine Is Off
A car’s battery is most at risk of discharging when the vehicle is not running. Without the engine running and the alternator charging the battery, when the car is off the battery can be more vulnerable to draining.
All drivers know that if you don’t turn your ignition over regularly, the car battery will die. Batteries need the electrical current from the car to charge, without it, they will drain completely over time.
Battery discharge can occur when the engine is off in the following scenarios:
Parasitic Drainage
Parasitic drainage is caused when the battery continues to be used, even when the vehicle is off. For example, a sensor or interior light may be faulty and continue to draw power from the battery when the battery is not being recharged by the alternator.
A parasitic drain can drain the battery so much when the car is off, that is it not able to charge back up normally when the engine is running.
A parasitic drain can impair the performance of your car’s battery, which can in turn impact other electrical systems and accessories in the vehicle.
A parasitic drain is a problem that can reduce the lifespan of your car battery and it can often be difficult to pinpoint the cause.
Headlights Have Been Left On
It can be difficult to leave the headlights on in a modern car, with all the alert chimes and automatic shut-off systems. However, it is not impossible for the headlamps to stay on when the car is off.
Headlights use up a lot of your car’s power and will drain up the power in your battery when the vehicle isn’t running.
Radio Is Still Playing
The radio is the same as the headlights, it uses power from the battery to function. If you leave the car and forget to shut off the radio, it will continue to draw energy from the battery and lead to battery discharge.
Listening to music while sitting in a parking lot might make waiting in the car for someone more enjoyable, but it can take its toll on your car battery.
Chargers Left Plugged in
Modern vehicles are often fitted with at least one charging port for smartphones and other accessories. Even if you remove your device, when the charger is left plugged in the battery will still be being used.
Whenever your car battery is being drained of power without the alternator working to recharge it, battery discharge is likely to occur.
Faulty Battery Terminal Connections
The condition of your car battery can put it at risk of draining too quickly. If the connections inside the battery are too loose or faulty, this can result in drainage, even when the battery is not being used.
The Weather
It may sound strange, but weather can impact the charge in your car battery. When temperatures are too high or too low, car batteries are more susceptible to draining too quickly.
Many drivers avoid this problem by keeping their cars parked in their garages, where the temperatures are less severe and damaging.
Old Car Battery
As with all parts of your car, over time the performance of your car battery will deplete. When the battery is old, it may struggle to hold its charge when the vehicle is turned off.
Over time, the battery cells and electrodes will not function as well as they once did and you will notice your battery is struggling to keep its charge.
Reasons for Battery Discharge Warning When the Engine Is On
The battery discharge warning can appear due to issues occurring when the car is off, but also when the engine is running.
If you notice the battery discharge warning message when you are driving – a time when the battery should be being charged by the alternator – one of the following reasons could be to blame.
Too Many Accessories
Running more electrical accessories than your car battery can handle can cause issues with battery power.
Whether it’s an aftermarket sound system and LED lights or too many devices charging and the GPS running, when the battery is giving more power than it is receiving, the risk of drainage is high.
Failing Alternator
Car alternators are designed to last for around 50,000 miles and when left longer than this, problems with the battery can occur. The alternator is essential for your car’s charging system and if this key component malfunctions, the battery will start to drain.
Weak/Damaged Battery
A weak or damaged car battery will not be able to charge quicker than it is being drained of power. If the battery is not maintaining charge when the alternator and other parts are working fine, the problem is with the battery.
In these circumstances, the battery will need to be replaced. Corrosion inside the battery terminal can also cause battery discharge. Rust and built-up deposits on the battery terminals will prevent it from charging as it should.
Faulty Ground Connection
All car batteries have positive, negative, and ground connections. Ground connections help to prevent fires in the battery but can also cause their own problems!
If the ground connection is faulty, the charge can end up heading towards the grounding connection, when it should be charging up the battery instead.
Damaged Serpentine Belt
The serpentine belt rotates and provides the alternator with the energy needed to do its job.
If the serpentine belt is stuck, broken, or slipping, the alternator won’t receive enough power and in turn, the battery will not be charged as it should be when the car is running.
Faults in the Charging Circuit
As well as a damaged serpentine belt, any problems in the charging circuit can cause battery drainage.
For example, faulty sensors or problems with the starter motor can all result in the car battery being unable to charge quicker than it is being drained of power.
How to Fix Battery Discharge Warning
Battery drainage is not an issue you should try to ignore. If you continue to drive with the battery draining more quickly than it is charging, you are not going to find yourself broken down at the side of the road before long.
Prevention is always the best way to avoid battery discharge. Remember to always unplug your chargers, check all the lights and accessories are switched off, and regularly check the battery for any corrosion or damage.
However, if you are already seeing the battery discharge warning message or light, there are a few steps you can take to solve this problem.
Charge the Battery
If the battery is running low on power, a simple recharge may be all that is needed to resolve the battery discharge problem.
There are standard chargers, smart chargers, and trickle chargers that can all be used to bring power back to your car battery.
Jumpstart the Car
All drivers know the power of a jumpstart, right? If battery discharge has caused you to break down at the side of the road, a fellow driver will be able to help you out by giving your car a jumpstart.
If a jumpstart is successful, you should run the engine for at least 30 minutes, this will give the alternator time to charge the battery.
Check the Battery Electrolyte
The electrolyte in your battery is an essential component for creating the chemical reaction to produce the electrical current. If the electrolyte levels are low, this can lead to power loss problems.
To check the electrolyte levels, look into the battery vents. If the battery cell plates are not submerged, there are not enough electrolytes in the battery.
Replace the Battery
Sometimes when you see the battery discharge warning this can mean the battery is past the point of no return.
If a jump start fails, the battery won’t charge when connected to a charger and the electrolyte levels are normal, there may be no other choice than to replace the battery.
If you have mechanical expertise, you can replace the battery yourself at home. Although this may save you on labor fees, doing this task yourself can be dangerous if you don’t know what you are doing.
If you buy a new car battery at Walmart, you can have it installed for free at their Auto Service Centers. However, for batteries bought from somewhere else, there is a fee of $10.
When you see the battery discharge message, make a plan to fix the issue as soon as possible.
The longer your battery is left draining more quickly than it is charging, the more chance you have of being left with a completely dead battery.
FAQs
How do you stop a parasitic battery from draining?
To prevent parasitic draining of your car battery, always make sure you turn off all lights and electrical accessories before you leave the car.
Also, remember to unplug any charging cables and check the glove box and trunk are completely closed. Drivers also need to check the radio hasn’t been left on when they switch the engine off.
Can a fully discharged battery be recharged?
Assuming the alternator and all other components in the charging circuit are in full working order, it should be possible to recharge a completely flat car battery. However, if jumpstart and using external chargers aren’t working, your flat battery will need to be replaced.
How long should I run my car after a jump start?
Following a jump start, it is wise to leave the car running for around half an hour. Drive your vehicle for approximately 30 minutes and give the alternator the time it needs to charge the battery. Charging will take longer if the engine is left idle.
Does revving the engine charge the battery faster?
Yes, revving the car engine will charge the battery faster. Revving causes quicker charging as it causes the crankshaft to turn more quickly, which makes the alternator belt turn faster.
What causes battery discharge?
Battery discharge is caused when the car battery is not charging as quickly as it is being drained of power. When the battery is in demand and not charging quickly enough, battery discharge can occur and cause performance problems for your vehicle.
Conclusion
If you have ever seen the battery discharge warning on your car dashboard and wondered what it means, now you have all the answers.
Battery discharge occurs when a car battery is draining too quickly and not charging at a fast enough rate, this can happen when the ignition is off or when the car is running.
When the battery discharge warning message appears, turn your engine over and go for a drive; the alternator will work to charge the battery while you are driving around.
However, if the battery is too flat to start the car, a jump start can help, or using a plug-in charger to power the battery back up.