The Proper Way To Jump Start a Car Battery

A dead or weak car battery can happen to anyone. Perhaps a map light was left on, or you sat parked longer than planned with the air conditioning on but the engine off. Cars sometimes develop their own internal electricity drain, which a mechanic must find, or maybe the car hasn’t driven for a few weeks. Plus, of course, all car batteries eventually get weak and fail without warning. The most consistent thing is that it never happens at a convenient time.

Jumpstarting the car is the first course of action, and anyone can do it.  This is why it is always a good idea to keep a set of jumper cables in your car. With them, you will have the opportunity to help a friend or stranger in need, and if it is you who needs help, it is much easier to get help from a fellow motorist when all they need to do is provide their car and a little bit of their time. Jumpstarting a vehicle is a relatively simple procedure, but some ways are safer than others, so Bud Brown Volkswagen wants to show you the right way.

Step One: Securing and Positioning a Booster Vehicle

The first step is to secure a booster vehicle. Size doesn’t matter. Little cars can jump-start big trucks and vice versa. The first thing you will want to do with the booster car is locate its battery. The vast majority of cars have their battery in the engine compartment. (Some models, usually sports cars, place the battery in the trunk). However, there is no standard location within the engine compartment, so the battery may be to the right or left, upfront, or to the back, though all will be easily accessible, as all will have to be removed and replaced at some point. Batteries used to be out in the open and easy to find. On modern vehicles, they may be under a plastic cover, though that cover should be marked by a battery icon and + and – symbols.

When you have located the batteries on both vehicles, you will want to position the booster vehicle as close to the stalled vehicle as possible while still giving yourself room to walk between the cars. Almost any jumper cables should be long enough to allow this.

Step 2: Locating Battery Terminals

All car batteries have two metallic protrusions with clamps attached. They are usually on the top of the battery, but some can be on the side. One will always be marked with a “+” for the positive terminal and a “-” for the negative terminal. Sometimes, the positive terminal may be identified by a red cap. 

If the battery is old, the terminal may be covered with a white or greenish substance. This is battery acid, and you will need to remove it. The most effective removal method is with a wire or stiff brush, but you can use a cloth or anything aside from your bare skin, as the acid will burn upon contact. Also, do not jump if a battery is cracked or leaking. The jump won’t succeed, and the leakage could ignite. In this case, simply replace the battery on the spot.

Step 3: Connecting the Jumper Cables

When connecting the jumper cables, there are four things to keep:

1. The clamps connected to the battery should remain in place
2. Red always connects to positive (+) 
3. Black connects to a negative (-) or a grounded part (explained in a moment) 
4. Never let the red and black clamps on one side contact each other when the others are connected to a battery. This will cause sparks and risk a short in the vehicle with the attached battery. 

Even the failing battery may have enough charge to create sparks upon contact with the other end of the cables. To best avoid contact sparks, follow this order in connecting the cables:

1. Attach a RED clamp to the positive terminal (+) of the DEAD battery.
2. Attach the RED clamp from the other end of the cables to the BOOSTER battery’s positive terminal (+).
3. Attach the BLACK clamp to the negative terminal (–) of the BOOSTER battery.
4. Attach the BLACK clamp to an unpainted metal part of the car’s engine, such as a bolt or bracket, of the vehicle with the DEAD battery. Some models have a grounding bolt marked with a (–) placed solely for this purpose.

The last step is the least followed, with people often connecting the black clamp to the negative terminal of the DEAD battery instead. This usually works, but it poses a risk. Connecting it to the final negative terminal can produce sparks. While jumping, the receiving battery produces hydrogen gas, which can ignite and possibly damage the battery and electrical components of the vehicle. It isn’t common, but the risk is there, so connect to an unpainted engine instead. After all the connections are made, make sure the cables are clear of any moving engine parts. 

Step 4: Jump Starting

First, start the car with the good battery. Next, try starting the car with the weak battery. If it does not start at first, wait a few minutes for the weak battery to build up a sufficient state of charge. Increasing the idle speed of the booster vehicle can accelerate this process. 

Step 5: Disconnecting the Cables

Once the car with the weak battery has started, keep it running while you remove the cables. Disconnect them in the reverse order that you connected them:

1. Black clamp from the jumped car
2. Black clamp from the booster car
3. Red clamp from the booster car
4. Red clamp from the jumped car

You should keep the jumped car running for 20-30 minutes after the jump to allow the alternator time to charge the jumped battery. Before shutting off the vehicle, make sure it is parked in a location where the battery can be jumped again if necessary. Some weak batteries are simply beyond charging, or there may have been a problem with the alternating charging process that caused the problem in the first place. 

Keep in mind that some batteries are too depleted to charge, or the starting issue might not be battery-related. Hearing a clicking sound when trying to jump-start the car may indicate a bad starter or solenoid needs replacing. This will usually involve a trip to a service center. May we recommend Bud Brown Volkswagen? Our service department is second to none. We always use factory replacement parts, and we keep a large supply of them on-site to help you get back on the road again.