Will the Car Battery Drain if the Negative Cable Is Disconnected? A car battery will self-discharge at a rate of 5-15% per month with the negative terminal disconnected. However, the alternative option of leaving the battery connected while it isn't being used will drain at close to 20% per week.
Can loose battery terminals drain the battery? The cables complete the electric circuit, so they don't leak power or kill the battery. However, the battery won't be charged properly as you drive, and it will get drained until empty.
Parasitic Drain - If the electrical devices in your car or the lights on your car are left running even when your ignition is off, they will suck the juice out of your battery slowly but dramatically. This is often eerily described as parasitic drain.
A parasitic drain refers to when your car's battery continues to drain even after the car's parked, and the amount of drainage is much higher than normal. Usually, it's a faulty accessory in the car causing the drain – for example, a sensor or interior light doesn't switch off automatically.
Usually, a battery cable will last anywhere from 50,000 to 100,000 miles. The battery cables that are on your car are used quite frequently. Due to this amount of use, it is easy for them to wear.
Electrical Fault
Any short within your car's wiring can cause draining issues. The alternator could also be a culprit. Battery usage seems infinite when you're driving down the road, and that perception is thanks to the alternator.
Loose or Corroded Battery Terminals. Loose or corroded battery terminals can impair your battery's ability to transmit power, preventing your vehicle from starting. You may also experience slow cranking or notice a rapid clicking sound when attempting to start the engine.
It's pretty easy to spot — typically, it's a white, blue or green-tinged covering on the battery terminal, cables or posts. Corrosion on or around your battery's surfaces can lead to increased resistance within the circuit, which can disrupt the electrical current.
A bad ground might not cause a battery to drain, but it will prevent it from properly recharging.
Poor ground connections are an often-overlooked cause of low charging output and alternator failure.
Disconnecting the negative (chassis lead) will protect the electrical side of the battery. Removing the battery and storing it inside will protect the physical battery.
Just like any good at-home automotive repair, you should start with all your tools ready to go, as well as safety equipment such as eye protection and gloves. Replacing battery cables is straightforward, and you'll need the following: A Screwdriver. A Socket Wrench.
However, DO NOT disconnect the positive terminal before the negative one. Doing so can cause an electrical short. Always disconnect the negative battery terminal first.
In some cases, it can be severe enough to deplete your fully charged battery overnight. Although you can test any circuit for a parasitic draw, this is how it works for a draw on an alternator, and all you need is a digital multimeter.
If your phone's battery is draining faster than usual, it either means you're using a lot of energy or your phone is not using energy efficiently. This could mean you're overworking your phone by running too many applications, or something is physically wrong with the phone battery itself.