Most of us know that electricity will only flow in a closed circle. If you break this circle at some point, it will not allow the electricity to flow into the system at all. It means that if you disconnect only one of the battery terminals, the system should stop working completely because there is a cut in one of the main points. But things are much more complicated.
Car battery issues highlights
- Possible reasons:battery age, driving conditions, drains, long sitting, electrical problems
- Types affected:all types
- Average age:4-5 years
- Most commonissues:low voltage, no crank, battery light, glitchy electronics
- Can you drive?only if it starts
- DIY fix:possible
- How much to fix?$150 - $250
Disconnecting battery terminals - why both?
If you are going to do some quick job in the vehicle, you may only disconnect the negative terminal and leave the positive one connected. But this may still cause some battery drain. Also, it makes it quite risky for longer periods. Once something touches the negative battery terminal, the system may start working. For example, some lost wire may touch the negative battery terminal and then the car's body or the cable that was put too close to the battery.
After such an occasion, the vehicle may drain the battery and this will be the best thing that can happen. In some cases, the current may flow without any control and even burn your vehicle if the problem is not addressed on time.
So, we would recommend disconnecting both battery terminals and putting the cables with connectors safely to the side so that they don't jump back to their normal place without you knowing that. Even if it's something longer than an hour or two, we would disconnect both terminals to avoid problems.
Which battery terminal should come first when disconnecting?
The only rule you should know: never disconnect the positive terminal first. Also, never connect the negative terminal first when you are done. If the positive terminal is connected, it will not cause any short circuits or other problems. If the negative terminal is connected but the positive is disconnected, the risk is extremely high and the wiring in your vehicle is in danger. It may even go to flames!
So, whenever you disconnect your car battery, make sure you first disconnect the negative terminal. After that, you may leave the positive terminal connected or take it off, too. But the most important thing to do is to disconnect the negative terminal first.
Also, it's extremely important to make sure that the cable is safely protected from jumping back and touching the terminal. This is a very common mistake that can cause a short circuit or even fire.
When is it important to disconnect the battery?
Here are some of the most common situations when you may need to disconnect the battery in your vehicle:
- you are going to repair something in the electrical system of your car;
- you want to reset a certain error code or check the engine light;
- you want to replace some part that is connected with electrical wiring in your vehicle;
- you need to replace the battery;
- you want to charge the battery;
- you are going on vacation for a couple of weeks and won't take your vehicle;
- your car got into an accident;
- some electrical modules in your vehicles have gone crazy.
This is not the full list of things that may make you disconnect the car battery. The most important thing is that whenever you are doing this, you should remember the most important rule: always disconnect the negative terminal first and when connecting the battery, always connect the positive terminal first.
Can my car go to flames if I make a mistake?
Yes, burning vehicles because of battery problems and bad connections are very common. If the negative terminal of your battery stays connected, it may lead to a short circuit and eventually, this will heat up the wiring in your car. When it happens, there is always the chance that the vehicle will be set to fire eventually. Of course, everything may still be OK, but the risks are quite high.
So, just follow the guidelines that we've provided you with in this article and stay away from danger.
About the authors
The CarAraC research team is composed of seasoned auto mechanics and automotive industry professionals, including individuals with advanced degrees and certifications in their field. Our team members boast prestigious credentials, reflecting their extensive knowledge and skills. These qualifications include: IMI: Institute of the Motor Industry, ASE-Certified Master Automobile Technicians; Coventry University, Graduate of MA in Automotive Journalism; Politecnico di Torino, Italy, MS Automotive Engineering; Ss. Cyril and Methodius University in Skopje, Mechanical University in Skopje; TOC Automotive College; DHA Suffa University, Department of Mechanical Engineering
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