Quick Answer: What Happens When You Disconnect The Negative Battery Cable?

Can I just disconnect positive terminal?

Just be careful and ALWAYS disconnect the POSITIVE terminal first.

Keep the battery grounded (negative is ground).

Try not to touch the positive wire on metal as it possibly could be holding some charge after you disconnect it..

What terminal do you disconnect first on a battery?

Always remove the negative cable first. Use a wrench to loosen the nut on the black/negative (-) end of the battery. Detach the black/negative (-) cable from the battery. Detach the red/positive (+) cable from the battery.

What happens if you connect positive to negative on a battery?

Connecting the positive terminal of each battery to the negative terminal of the other battery will result in a huge surge of electrical current between the two batteries. … The heat can melt internal and external battery parts, while the pressure from the hydrogen gas can crack the battery casing.

How long does it take for a car computer to relearn?

The real answer is it depends on how you drive. It could take as little as 30 minutes if you drive exactly in a specified way. Other times it may take a week or so. In the end, it does matter though because the engine control module is constantly learning and making sure your car is running optimally.

How do you keep a car battery from going flat when not in use?

If so, here are some things you can do to save your car battery when it’s not in use.1) Use a trickle charger or battery conditioner. … 2) Avoid turning your car on and then off again. … 3) Avoid short journeys. … 4) Drive your car for 15-20 minutes at a time. … 5) Alternate trips if your household has more than one vehicle.More items…

How long do you leave battery disconnected to reset ECU?

Disconnect both positive and negative cables from the battery, then touch positive and negative connectors for 30 seconds, that will do it.Log in.Full Site.Top.

Which battery terminal Do I disconnect for storage?

The low-tech solution is to disconnect the negative battery cable. You’ll likely lose the stereo presets, time and other settings. If you want to keep those settings and ensure that your battery starts the moment you return, purchase a battery tender, also known as a trickle charger.

What happens if you connect the negative terminal first?

The negative cable is connected to the body/chassis of the car. … If you connect the negative first, then the positive, if you happen to touch the wrench to something metal while it is touching the positive terminal, that’s a short – because the chassis is already connected to the negative battery terminal.

When connecting a car battery which terminal do you connect first?

“Positive first, then negative. When disconnecting the cables from the old battery, disconnect the negative first, then the positive. Connect the new battery in the reverse order, positive then negative.”

Will disconnecting negative battery cable do?

“But the complication is, whenever you disconnect the cable from the battery, you have to make sure it’s secured somewhere so it’s not contacting the ground or any of the positives. … If the cable end is touching the negative terminal or is even in proximity to it, it could create a spark and cause a fire.

Which battery cable should you disconnect when working on a vehicle?

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.

Will removing the negative battery cable reset computer?

Will Disconnecting a Car Battery Reset The Computer? The answer is, maybe. Disconnecting the battery for a short time may not do the trick because the car’s computer, or ECU, still has some current in it. Waiting for over 15 minutes after disconnecting the engine will help ensure the equipment is reset.

Will touching battery cables together to reset computer?

Whenever you touch the battery cables together and drain the capacitors the clock will lose its memory, the radio stations will need to be reset, all fault codes will be cleared, the outside temperature may take some time to relearn, any systems with security codes will need to be reset and the computer will need to …

How long does it take for a car computer to reset itself?

The amount of time can vary based on the vehicle. In some cases it can take up to 100 miles for all of the computer monitors to completely reset. Q. We purchased two 2002 Honda CR-Vs about six months apart.

Do I need to disconnect both battery terminals when charging?

Remove either battery terminal from the battery (creating an open condition) and charge it that way. Also keep in mind that dirty or corroded battery connections can also trick your smart charger into thinking there is a problem. … A weak battery may have 11.5 volts.

Can you just disconnect the negative terminal?

Disconnect the negative terminal. That way, you don’t risk a catastrophic short-circuit if you accidentally touch your spanner against the bodywork or a metal component whilst you’re removing the positive terminal. Disconnecting the neg terminal will be just as effective a method of isolating the battery.

Why do I have to disconnect the negative battery terminal first?

When a car is negatively earthed then it is prudent to take off the negative terminal first and connect it last. … The grounded terminal should be disconnected first to ensure that a battery dead-short does not occur, should the spanner disconnecting the other one contact a nearby grounded metal part.

What happens if you disconnect the positive terminal first?

It can fall across either terminal and the car and nothing will happen. If you disconnect the positive terminal first and you drop a spanner, it is possible for it to fall across the positive terminal and any earth on the car, with spectacular and possible dangerous results.