QA

Question: How To Properly Disconnect A Battery

Which battery terminal do you take off first?

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.” When you are replacing your car battery, It isn’t always easy to remember the order in which to disconnect and reconnect the terminals.

Why do you disconnect the negative first?

The reason they say to remove the negative first is because it is safer for you. The negative cable in all modern cars is attached to the chassis of the car. SO when you put your wrench on the negative post to loosen it, and the wrench hits the chassis, nothing happens.

Is it OK to just disconnect the negative terminal?

In order to disconnect the battery, all you have to do is remove the cable from the negative port. If the cables do make contact or even get close, it could do a number of harmful things to your car, including frying your alternator, damage the cables, or worse, cause serious injury to yourself or others.

What happens if you disconnect the positive terminal first?

If positive terminal is removed first then chances of a spark are more if this terminal touches the body through the metal spanner or wrench you are opening with is grounded accidentally and may end in flames because lot of combustible material is around. And chances of this accidental touch are very high.

What happens if you connect negative first?

Getting to our question, Always while connecting the cables to a car battery, connect the positive terminal first, then the negative and the ground. If you connect negative first, there are chances of short-circuiting. The battery might explode. Holds a temporary charge on the battery.

Is it OK to just disconnect the positive terminal?

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.

What happens if you disconnect the battery while the car is still running?

Disconnecting the battery while the engine is running could cause the electricity supplied by the alternator to go beyond the range deemed safe for the ECU, potentially frying the ECU. Again, should this happen, the vehicle will die, leaving you stranded.

Do I need to disconnect both battery terminals when charging?

Always disconnect the negative (usually black) lead first and reconnect it last, otherwise you could end up getting a nasty shock when you touch the positive terminal. The terminals are usually connected to the battery by a clamp, which is loosened or tightened by a bolt on the side.

How long will a car battery stay charged if disconnected?

When stored properly out of the car in a secure place, a detached car battery has the chance to last up to six months. Just like any other car battery, it will need charging, but not as often as if it were attached. Giving the battery a charge around every 12 weeks is a good rule of thumb.

How do I choose a battery disconnect switch?

Design. It’s also crucial to pick a battery disconnect switch that is perfectly designed for your vehicle. The device should be big or small enough to fit the battery. It should also have some extra protection to prevent short circuits and other potential damages.

Why do you connect the positive terminal first?

When jump starting cars always positive cable is connected first! Reason is simple, if cable drops and touches car nothing happens cause cars are still isolated – missing negative. But if negative is connected first, dropping positive will short both cars.

How do I know if my alternator is disconnecting my battery?

First, open the hood and start the engine. Remove the negative battery cable with the engine running. The alternator is likely to be damaged if the car stalls or stalls. This is because the alternator does not produce enough electricity to keep the engine running on its own.

Do you put red or black on first?

Attach the red jumper cables first. Start by clamping one red cable to the positive side of the battery that won’t start. Then attach the other red clamp to the positive side of the working battery. Next, clamp one black cable to the negative side of the working battery.

Is it better to disconnect the positive or negative battery cable?

Do not disconnect the positive (+) battery cable first! The negative () cable is the ground cable; it is always connected to the frame or body metal and can safely be disconnected first with no chance of causing sparks. By the same token, always reconnect the positive cable before connecting the negative cable.

Should I wear gloves when changing car battery?

While not necessary to remove the battery, rubber gloves can add a small degree of safety when dealing with electricity. Never connect any cables that shouldn’t be connected. That means avoid swapping the wrong battery cables and battery posts or putting the cables anywhere they’re not supposed to go.

What happens if a wrench touched both battery terminals?

Ray: The danger from car batteries is not so much electrocution as it is explosion. If you touch both terminals with a metal wrench, for instance, you can create a spark that can ignite hydrogen gas in the battery. That can send pieces of battery and battery acid flying everywhere.

What happens when you cross the jumper cables?

Touching the jumper cable ends together When the jumper cables are hooked up to a battery, touching the cable ends together can create sparks. In some cases, the sparks can ignite the hydrogen gas escaping from the battery, causing an explosion.