A cold Monday morning, but duty calls. We get into the car and… silence. The starter doesn’t budge, starting the engine is out of the question. What actually happened and why?
Discharged battery can be a real pain – especially when the car seems to be absolutely necessary. Nerves, however, will not help. You need to look for the cause of the problem and prevent its recurrence in the future.
What causes a discharged battery?
There are many reasons why car one day works perfectly, and the next day will not start, there are many reasons. The most common ones include:
- old battery with limited capacity and too low starting current, which as a consequence of excessive wear can not turn on starter,
- incorrectly matched battery to the engine, which can lead to overcharging or undercharging, both of which reduce battery life,
- malfunctioning alternator, which makes the battery is not properly charged when the engine is running. As a result, current is depleted faster than it is recharged – a situation typical for cars driven on very short distances (where even a functioning alternator may have performance problems),
- uninterrupted operation of on-board devices – controllers, central locking system, alarm, radio, cameras monitoring the vehicle’s surroundings – and leaving the car with lights on,
- poor quality and improper installation of additional devices causing excessive power consumption,
- current “leakage” in different parts of the electrical system,
- dirt and moisture that can cause “creepage currents”.
The above list covers the most common cases. Experience shows, however, that they do not end there. It is not uncommon that there is more than one cause of discharged battery.
Discharged battery – what to do
If battery refused to serve, the first thing to do is to consider when it was last replaced with a new one. Unfortunately, battery life is not unlimited and many batteries begin to fail after only 5-6 years. In very few cases it happens that battery will last up to 10 years.
So if battery is old and worn out, the only solution is replacement. Otherwise, even when fully charged, especially in winter conditions, you can expect rapid re-discharge. It’s a waste of effort – especially since even good quality batteries are not particularly expensive nowadays (remember to return old device to the point of sale).
If the existing battery has not yet reached the age of retirement and no objective circumstances explain its discharge, you need to look for the cause. We check the degree of charge of the battery, as well as the current supplied by the alternator. If the latter does not work efficiently enough or not at all, the battery is not charged. The car uses electricity, but there is no way to replenish it. With more time at your disposal, you can disconnect the battery and then charge it fully with a charger, then leave it for a day or two. If it discharges on its own, it is the battery itself that is causing the problem.
Checking power consumption
In the absence of any obvious irregularities, it is necessary to verify the power consumption of individual on-board devices. For this you will need a meter and a little patience – and preferably the owner’s manual or service book, in which the individual fuses will be described. Disconnecting one fuse after another will allow you to check whether any of the devices has started drawing more current than it should (which could be the result of a puncture in the electrical system).
Verification of the state of the electrical system
Another thing that should be checked are wires and clamps. Loose clamps, for obvious reasons, will not allow to start the car – that’s one thing. The second is dirt and snow on the contact elements. They can also cause leakage of current and cause battery discharge. Solid cleaning of connections in some situations may be sufficient “repair”.
If none of the above simple tests indicated the solution to battery problems, it is worth going to a car electrician, who will professionally check the electrical system. The cause may not be obvious – and only the eye of an experienced professional will be able to spot it.