How to remove a car battery correctly without damaging it

The battery is one of the main elements of a car. An energy source with a capacity of 12 volts supplies electricity to start and operate the engine and car electronics. Powers the alarm when the engine is turned off. Sometimes it is necessary to remove the battery for recharging, maintenance, winter storage or replacement with a new battery. It is important to know how to remove the battery correctly. When removing the battery for the first time, it is recommended that you read the instructions for the car.

Preparing for work

  Before starting work you must:

Turn off the headlights, air conditioning, heater, player, on-board electronics and other energy consumers.
Turn off the ignition and put the key in your pocket so that there are no problems associated with getting into the car with the battery disconnected.
After turning off the ignition, turn off the ground switch, if the car has one. This will protect the on-board computer from power surges and accidental short circuits.
Wear long sleeves and gloves to protect yourself from accidental burns if battery acid comes in contact with your skin.

Why do you remove the battery for the winter?

Guys, everything is simple here - they remove it so as not to “kill” the battery! If the car is not in use, but the terminals are connected to the battery, then the discharge microcurrents are still present, of course, for some the leakage is much larger, for others it is much smaller, but in any case it is present (by the way, how to check it, read here ). Also, do not forget about self-discharge currents; even the most ideal battery can discharge itself during a long period of inactivity. YES, to be honest, batteries are not always clean on top, that is, they may contain dirt, moisture (for example, precipitation, evaporation, etc.), antifreeze and much more. All this can drain the battery, albeit slowly but surely.

Battery location

The battery is not always located under the hood next to the engine. In some cars, the battery is located under the driver's seat or under the rear seat. To remove the battery from under the seat, you need to partially dismantle it using 8 and 13 mm wrenches.

On a Citroen Xsara Picasso, for example, keys are not needed to remove the battery from under the seat. The chair is equipped with different levers for easy access to the battery. In German cars the battery is often installed in the trunk. In some cars, the battery is located under the front or rear fender. You must first remove the wheel or remove the bumper, then just remove the battery.

If the battery is not in its usual place, you can look in the car manual or find out via the Internet the location of the battery in a given car model.

Required Tools

To work, you will need 8 or 10 mm ring wrenches to loosen the terminals and 12 or 13 mm to remove the fixing tie. A rag will help to remove dirt and dust.

Algorithm of actions

There are several ways to remove the battery. Car enthusiasts have found the most effective one and recommend using this particular algorithm when removing the battery.

First of all, it is necessary to warm up the battery to normal temperature when it is in operation; it is recommended to do this while moving.
Next, you need to remove the negative terminal and wait for the computer to reset, 3 minutes is enough. Then the terminal is put back. If the battery has been completely taken out of the car, you must first connect the positive one.
Then, without touching the pedal - this is very important, you need to start the engine and warm it up for 10-15 minutes. During this time, information will be collected from the on-board system sensors.
After 15 minutes the ignition is turned off to allow data recording to take place.
Next, the car starts and accelerates to a speed of approximately 50-60 km/h, followed by a complete stop.
The ignition is turned off again, this time the computer records the readings of the sensors operating in motion.

When using a car for a long time, it often happens that the computer memory produces false codes, signaling various malfunctions - errors that affect the car. To get rid of the problem, you need to periodically reset the computer by removing the terminals. Everything seems simple, however, the risk of harm is high, so be sure to approach the process prepared and with extreme care.

Is it possible to remove the battery from a running car?

It is strictly forbidden to remove the battery while the engine is running.

  When the car is running, the battery plays the role of a voltage stabilizer. When the terminals are disconnected, the voltage surge produces a welding arc between the terminal and the battery terminal.

The consequences can be irreversible: failure of the synchronous generator, battery, and all electronics. There is also a high risk of fire. According to experts, it is possible to remove the battery from old Soviet-made cars, for example the Volga, while the engine is running.

On forums, many people share their successful attempts to remove the battery while the engine is running, but is it worth the risk?

Removing the battery for the winter: a mistake or a necessity?

If you use your car relatively rarely in winter, that is, it sits idle for weeks, removing the battery is absolutely justified. Even in summer, a battery that is not in use loses its charge over time due to microcurrent leaks, which are present even on a new car. At negative temperatures, such phenomena intensify many times over. It is not without reason that experts advise charging the battery with an external charger at least once every two weeks during the cold season, even if the car is used intensively.

So the answer to the question whether it is possible to remove the battery from the car for the winter if it will be idle a lot is affirmative. Moreover, many drivers, if severe frost is expected, remove the battery even at night, and this behavior is absolutely justified. Another thing is that not everyone has such an opportunity, and more often they are simply overcome by laziness.

How to properly remove the battery from a car

It is necessary to gain access to the battery depending on its location, then remove the fabric thermal protection and the plastic noise insulation casing, if any. Take a break for a few minutes to allow the electrolyte vapors to dissipate.   

  Some people don’t see the difference in whether it’s a plus or a minus to remove from the battery first. Determining plus and minus is not difficult: the positive terminal always has a red wire. The battery has + and - marks. First of all, you need to disconnect the ground, the negative terminal, in order to open the electrical circuit and de-energize the car body.

If you disconnect the positive first, a short circuit in the circuit will be fatal.

Also, if metal parts of a car or a tool accidentally come into contact with the positive terminal, electrical burnout may occur. When the minus is disconnected, no short circuit will occur.

Is it possible to shoot with the engine running?

There are two camps here - some say that it’s possible and nothing bad will happen, others that everything that can be burned will burn!

Personally, I think that you can remove the battery for a short time, for example, to start a neighbor’s car that is completely dead (and there are no wires for lighting), then quickly remove it and put it back.

By the way, in this way you can check the functionality of the generator, watch my video (if you don’t want to wait, skip straight to 14:21 minutes).

BUT you should do everything VERY CAREFULLY, let’s go point by point:

Short circuit . Actually, when the engine is running, the generator generates electric current; accordingly, the plus terminal goes to the plus, and the minus terminal goes to the minus. If you remove the battery, DO NOT IN ANY CASE ALLOW the positive terminal to come into contact with the car body, otherwise a strong short circuit will occur, and then all the wiring and electronics may burn out! After all, the generator can produce quite strong currents. That is, the positive terminal must be isolated from the metal parts of the body, because it is through it that the mass flows, that is, the negative part is connected.
Voltage fluctuations. Many people wrote to me that “when you remove the terminal, all the electrics can burn out (and it’s not even a short circuit), but simply from a power surge.” I think this is, to put it mildly, “not true.” Why? I justify it - look, a generator is not a “dumb” dynamo machine, it is essentially a very smart unit, it has a special “ voltage regulator relay ”. What it does is simply stabilize the voltage, that is, it does not allow it to exceed the 14.5 Volt level. After all, in fact, a generator at high speeds can produce 15 or even 17 Volts, such a voltage will be destructive for most devices, so this regulator “stabilizes” by cutting off excess voltage from above. So, if we remove the battery, then again nothing bad will happen, the voltage in the network will remain the same as it was from 13.8 to 14.5 V. DAMN WELL, WHAT SHOULD HE JUMP FROM? If you want to play it safe a little, you can give a load in the form of headlights, a stove, heated windows and seats, then the voltage will drop to about 13.7 - 14V, that's all! And in fact, the battery is nothing more than a current consumer (load); if it is undercharged, it receives charging from the generator; if it is charged, it receives nothing! WHY DOES IT ALL HAVE TO BURN, PLEASE EXPLAIN?

Wiring. The wiring is also “nonsense”, it won’t melt, nothing will happen to it. Again, the voltage regulator stabilizes everything. If you follow this logic, then if the terminal on the battery has oxidized and the charge does not flow into the battery, that is, it is, as it were, disconnected (all your electrics will burn out and all the wires will melt), isn’t it nonsense?

Therefore, nothing will really happen to your generator if you remove the battery from a running engine. THE MAIN THING TO REMEMBER IS THE POSITIVE TERMINAL.

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How to remove terminals from a battery

The removal sequence must be strictly followed:

Using an 8 or 10 mm wrench, loosen the negative terminal without unscrewing it completely. Carefully remove. If the terminal does not budge, you must carefully twist it left and right, then remove it. It is recommended to wrap the removed terminal with polyethylene or fix it to prevent accidental short circuit.
Then loosen and remove the “plus” terminal in the same way, insulate it with polyethylene or fix it. If, when removing the positive terminal, a spark jumps between it and the contact, it means that not all devices are turned off or the car’s wiring is faulty.
Using a 12 or 13 mm wrench, unscrew and remove the fastener securing the battery.

If the terminal is stuck

If there is incomplete contact between the terminal and the battery or if moisture gets on the contacts, a spark that appears under load solders the contact. A white coating indicates that the terminal is stuck.

If the terminal cannot be removed and is covered with a white coating, do not knock it down or knock on it!  

The battery terminal or housing and plates may be damaged. It is necessary to carefully remove the plaque with a stiff non-metallic brush. It is useful to use WD 40 fluid. Then carefully twist left and right and, using a screwdriver as a lever, remove the terminal. Afterwards, be sure to remove any remaining liquid from the contacts and clean the terminal from deposits.

Possible difficulties when removing the battery

In a car with an injector and on-board electronics, after removing and installing the battery, all saved data is often reset. It is better to entrust battery removal from premium and elite class cars, for example, Porsche, Opel, Mercedes, BMW, Volkswagen, Jaguar, Citroen, Bentley, to the specialists of the service station of an official dealer. With the majority of foreign cars equipped with an electronic control unit, there will be no big problems. All you have to do is set the time on the clock and tune the radio.   

  When the battery is disconnected, the alarm can turn on the alarm mode, closing all doors and activating the siren. Be sure to turn off the alarm before removing the battery. You can leave one door open. After returning the battery to its place, you need to check the operation of the alarm. If the radio has a security PIN code, you need to make sure that it is entered, otherwise after reinstalling the battery you will have to configure the functions again.

Safety precautions

During battery operation, hydrogen is released, which can explode from a small spark. All work with the battery must be carried out outdoors or in a well-ventilated box.

The battery is very heavy - the handle may not hold it. Properly hold the battery by the bottom when carrying it.

If acid battery electrolyte gets on your skin or clothing, immediately rinse the damaged area with a solution of baking soda or plenty of water.

Alkaline battery electrolyte that gets on your skin or clothing is neutralized with a 10% solution of acetic acid or citric acid.

How to lock or open a car without a battery

The alarm key fob will not be able to open or close a de-energized car. You should always have a regular key in stock. You must lock all doors and trunk with the key. Foreign cars most often have one lock cylinder. On the inside of other doors, above the handle, there is often a key that blocks the door lock.

You need to press a key and slam the door. In other options, a special switch located at the end of the door under a plastic plug will allow you to close the door. You need to insert the key into the hole, turn it clockwise until it stops, remove the key and slam the door.

After installing the battery in place, the door will open using the remote control.

Removing the battery is easy. The main thing is to strictly follow the sequence of operations. Owners of cars with on-board electronics should still contact specialists.