Do I need to disconnect positive terminal?

It's important to disconnect the negative side of the battery first, otherwise you can cause an electrical short if the positive is removed first.
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Can I leave the positive terminal connected?

You will be fine. Disconnecting either cable works. The reason they say to disconnect the negative and not the positive is because while taking the positive connection off with a wrench if you happen to touch anything with the wrench while it's on the positive terminal it can arc and be dangerous.
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Do I need to disconnect both battery terminals?

It is a good practice to always disconnect your negative battery terminal first, to minimize the risk of sparks that can lead to car electronics damage and battery explosion. Once you have located the negative terminal, use the wrench to free the nut that tightens the terminal.
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Should you disconnect the positive or negative terminal?

Disconnect the Battery Cables

Make sure you disconnect the negative terminal first. Lay the disconnected negative cable carefully to one side, making sure it's well away from the battery terminal. Disconnect the cable from the positive battery terminal in the same way, then lay it to one side.
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What happens if you only disconnect the positive terminal?

when the positive terminal is disconnected, it will arc when it comes into contact with just about any unpainted metal part of the car. The terminal doesn't have to touch a metal part directly, it can (and will) go through metal tools (like a spanner, screwdriver or pliers).
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Which battery terminal to disconnect first, connect first?



Do I disconnect the positive or negative to check the alternator?

You can check the alternator by simply starting your car and then disconnecting the negative battery cable. Be careful doing this, though, because there are a lot of moving parts in your engine compartment that could cause injury.
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Is it OK to leave car battery disconnected?

When you disconnect the battery from your car before you leave, you can avoid replacing it and spending money on repairs once you return. Keep in mind that even when a car is not in use, certain components—the clock and on-board computer, among other electrical systems—will still drain the battery.
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What does disconnecting the negative battery cable do?

If you remove the negative clamp and inadvertently complete a circuit to ground, there will be no current flow because the ground clamp is already grounded. Subsequent shorting of the positive terminal to ground will then produce no current flow because the current has no return path to the negative post.
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Which battery terminal do you disconnect for storage?

If you plan on storing a vehicle for an extended period, it's advisable to disconnect at least the negative terminal from your car battery. This prevents unnecessary battery drain, as a fully charged battery can hold its charge for 6-12 months if you do this.
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Will disconnecting car battery harm computer?

Disconnecting your car battery will not cause any permanent damage to your computer or ECU (electronic control unit), but it can have some adverse effects. Those include canceling your preset radio stations, forgetting learned shift points, and your car's ideal fuel/air mixture.
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Should you disconnect battery if car parked long term?

If you don't have access to an outlet - say, in a long-term airport parking lot - your second option is to disconnect the battery. That'll preserve the battery's charge, so when you reconnect it, the truck should start right up.
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Which battery terminal must be disconnected first and why?

Disconnect the negative terminal of the battery

You should always remove the negative battery terminal first, to reduce the risk of sparks which can make the car battery explode. Once the negative terminal has been located, use the wrench to loosen the nut that holds the terminal.
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How do I keep my car battery from dying when not in use in winter?

Tricks for Keeping Your Car Battery Charged in Cold Temperatures
  1. Park your car in the garage, away from the wind. ...
  2. Pause before turning on accessories. ...
  3. Juice it up! ...
  4. Keep your battery free of dirt and debris. ...
  5. Get your battery checked before winter hits.
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How long can a car battery sit unused?

Answer provided by

The good news is that the new battery can sit unused for two to four years and still work—as long as it's properly stored and maintained. Your unused car battery can be safely shelved for years if you: Store the battery upright. Keep it in a dry, well-ventilated area.
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Should batteries be removed when not in use?

DO preserve battery life by switching off a device and removing the batteries when it's not being used, and is not expected to be used for extended periods of time. DO practice proper battery storage by keeping batteries in a cool, dry place at normal room temperature.
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When should I disconnect car battery?

If a vehicle and its battery are left unattended for a long period, probably a month, then it might result in the damage of the battery and could even introduce the need for a replacement. Therefore, it is recommended to disconnect the battery if in case you intend to go on a vacation or such.
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Does disconnecting battery cause problems?

Disconnecting or replacing a battery on a computer-equipped vehicle may cause starting, driveability and a number of other problems, including loss of air conditioning, power accessory functions (door windows, seats, sunroof), false warning lights, even damage to certain electronic modules!
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Which terminal do you take off to check your alternator?

First, test it with the engine turned off.
  1. Turn the engine off.
  2. Turn on your voltage meter and set it to DC volts.
  3. Connect the positive lead to the positive terminal (+) on the battery, then connect the negative lead to the negative terminal (-) on the battery.
  4. Check the battery voltage on the voltage meter.
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Can an alternator drain a battery?

Contrary to its purpose, an alternator can drain a battery. It's rare, but it's possible. A draw on the battery only occurs if there's a problem with either a component in the alternator itself or connections to it.
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Does an idling car charge the battery?

Does the Battery Charge if You Let the Car Idle? The simple answer to this question is yes, your car's battery will start to charge as long as your engine is running.
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What kills your car battery?

What may drain a car battery when it's off are things such as interior lights, door lights, or even bad relays. While your engine runs, the alternator recharges the battery — which is why you typically don't have to worry about the battery dying while you're blasting the radio on your drive to work!
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How often should you start a parked car in winter?

The battery runs down when the car lies idle. To prevent the battery from getting discharged, ensure that you crank up the engine once a week. Leave it running for 10 to 15 minutes so that the alternator refills the juice.
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What happens if you connect a negative battery terminal to a positive?

If the positives and negatives are switched, the battery will try to compensate and make the negative 12 volts into a positive charge resulting in a huge surge of power and an enormous amount of heat to be produced.
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Can you touch negative battery terminal?

For a human touching a car battery, the skin has a very high resistance, leading to low current; and the battery has a low voltage, leading to low current. Even though a car battery can provide high current if connected properly, your body does not draw this high current.
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