Car batteries help start the engine by supplying power to the starter motor and other important components. But much more important is their function when the engine is not running. Because then the required current for all switched on consumers comes exclusively from the battery. The more consumers switched on, the greater the power consumption is, of course. In modern vehicles, in which more and more electronics are being installed, the consumption is generally higher than in older vehicles. However, if winter with cold temperatures is added to the mix, the car battery is put under even greater strain. On the one hand, this is because the chemical processes run more slowly and, on the other hand, because additional consumers are needed.
For this reason, it is worth knowing the biggest power guzzlers:
As soon as the vehicle is running, the alternator takes over the power supply. Of course, the more revolutions per minute, the more watts are generated. In idle mode, on the other hand, just 150 watts are consumed. Conversely, this clearly shows that when stationary or even with the engine switched off, as many consumers as possible should be switched off.
How long does a battery last?
Vehicle batteries do not have a classic expiration date. However, manufacturers specify certain time periods until which the battery should be used. Only after this date is a recharge necessary before the battery can be installed in the vehicle. The time period varies from manufacturer to manufacturer. At opel, for example, it is max. 12 months, 15 months for VW and up to 18 months for Ford. Basically, it can be said that the voltage should not fall below 12.4 V during installation. All batteries below 11V voltage can no longer be saved by charging, because the decomposition process is then already too advanced and the required power can no longer be retrieved.
How long a built-in battery lasts depends on the type of battery and the ambient temperature. Lithium-ion batteries, for example, discharge by just 2% per month at around 20° celsius. With lead-acid batteries, the value of self-discharge varies between 4-6%, with others it can be 10% or more. In addition, a modern vehicle also consumes electricity when it is switched off, as many control units and electrical consumers remain active even when the vehicle is switched off. This discharges a battery on average within 3 – 4 weeks.
But more exciting is the question of how long a car battery will last if other power consumers remain switched on. It is not uncommon for the active turn signal to be forgotten when parking in the evening, or for the lights not to be switched off. But does that really mean that the battery is dead in the morning?? Not necessarily. Depending on the ambient temperature and if the battery is intact, the car can still be started without any problems even after 10 hours of continuous operation.
The situation would be different if the hazard warning lights were to shine through the night. In this case, the battery would be completely discharged after 5 – 6 hours at the latest. Even leaving the car radio running when the engine is switched off costs electricity, which, depending on the power of the radio, would cause rapid battery death. The discharge time is always dependent on the ambient temperature. The colder it gets, the faster the car battery loses power. This is why a car battery often gives up the ghost in winter.
How can the life of a car battery be extended??
It is very easy to extend the life of a car battery. Even though most vehicle batteries are considered maintenance-free nowadays, it is still worthwhile to give them a little time now and again. The following tips can be done quickly and easily:
- Make regular trips of at least 30 minutes or charge the car battery with a charger every 1-2 weeks
- After the vehicle has been stationary for a longer period of time, or. After a longer period of discharging by power consumers, it is imperative to take a longer trip
- Do not switch on unnecessary power consumers such as radio, heating and lights until the engine is running
- In winter: do not switch on lights, windshield wipers, radio, fan, heater, rear window heater and seat heater until the engine is running and switch them off again as soon as they are no longer needed
- keep an eye on the fluid level, keep the poles clean and coat them with pole grease, at least once a year
- check battery voltage every two weeks with a voltage indicator
- Do not tip car batteries over a long period of time, as corrosive acid can leak out
- Carry out jump starting in the correct sequence
- Do not electrostatically charge the battery housing when cleaning it
- Transport the battery carefully
- Avoid overcharging with an external charger
How to recognize a weak battery?
In modern vehicles there are so-called "intelligent battery sensors", constantly measure the voltage, current and temperature of a car battery. You will inform the driver accordingly if the values are out of the norm. In addition, of course, anyone can measure the voltage with a voltage indicator.
But there are also two very practical indicators of a weak battery. The first one is when the starter doesn’t start right the first time. The second indication is when the dipped beam dims quickly after switching off. Then a longer drive is advisable to recharge the battery.
How to change a car battery?
If longer journeys and the other tips mentioned no longer help to refresh the battery voltage, a battery change is necessary. There are a few things to keep in mind. For example, all power consumers must be switched off before the vehicle battery is removed. In addition, first the negative terminal cable and then the positive terminal cable is removed. It is advisable to wear gloves when carrying out the work so as not to injure yourself with any acid that may have leaked out. The new car battery installed should be the same battery type and have the same dimensions as the old battery. However, it is perfectly possible to use a starter battery with a higher power rating. In addition, make sure that the batteries are of high quality, such as the original starter batteries supplied by the vehicle manufacturer.
It is important to clean the contacts and spray them with pole grease or pole spray before installation. To coat. This is the only way to protect them from oxidation. Then connect the new battery first with the plus pole and then with the minus pole. After installation, it is necessary to register the new battery in vehicles with an energy management system so that the battery sensor provides correct values. It may also be necessary to reactivate some power consumers by code after changing the battery. This includes car radios, electric windows and also alarm systems.
How does a jump start work?
But a new car battery or charger is not always readily available. Many therefore try to start the car first. However, this is only possible if there is still residual voltage in the battery and the vehicle is equipped with a manual transmission. Attention please do not try with a vehicle with automatic transmission!
For the push, the procedure is as follows: in the broken down vehicle, with the ignition on, engage the second gear and let the clutch come after a few meters. But be careful, if the car does not start immediately on the first few meters, unburned fuel can get into the catalytic converter and damage it.
A more sensible alternative to starting the engine is to charge the car battery with the aid of a jumper cable and another vehicle. For this it is important that both vehicle batteries have the same voltage and the vehicles are not in the rain or. Do not allow the terminals to come into contact with water. In addition, the following steps should be followed in advance:
- All power consumers such as radio, heating, light etc. Switch off
- Apply the handbrake
- Take the car out of gear
- Switch off the engine
Next, attach the red jumper cable to the positive terminal of the donor vehicle and then attach it to the positive terminal of the dead battery. Now connect the black starter cable to the negative terminal of the donor battery first. Attach the other end to an unpainted metal part in the engine compartment of the broken down vehicle. This can also be a part of the bodywork. Important: do not connect the black cable to the negative terminal of the dead battery.
Once all jumper cables are in place, the intact vehicle can be started and then the broken down vehicle can be started. However, the start attempt should not last longer than 15 seconds. If nothing happens, all pole clamps should be checked again for correct fit. If there is still no movement, the vehicle must be towed to a workshop. If the starter motor spins, but the engine does not start, stop the process immediately. Obviously, there are more serious defects than just a weak battery. At this point a professional should take a closer look at the car.
If the broken-down vehicle could be started, however, the engine must continue to run and one of the larger electrical consumers, such as a starter, must be switched off. Switch on the fan or the rear window heater. In the meantime, the jumper cables can be removed again. Here it is important to first disconnect the black cable, then the red one. Then switch off the electrical consumer again, but keep the engine running.
The breakdown vehicle should now be taken on a longer cross-country trip. Otherwise, the car should be hooked up to a charger so that the vehicle battery can be fully charged again. If it is not possible to fully charge the car battery again, a battery change is unavoidable.
Just quite popular is an alternative jump start, where the two vehicles are connected to each other via the cigarette lighter with the help of a special jump start cable. However, it should be noted that most cigarette lighters only work when the engine is switched on. In addition, neither the electronics nor the wiring and the electrical protection of the cigarette lighter are designed for such high current flows. Therefore we recommend to better rely on the conventional method of jump starting.
Regular care increases the service life of the vehicle battery
In principle, deep discharges should of course be avoided in your car battery. Together with the above tips, it is easy to extend the life of the vehicle battery. If the end has come, it is worthwhile to pay attention to high quality when choosing a new car battery. Our service team will be happy to advise you on this.