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Perhaps your car is acting up, sometimes it starts and other times it doesn’t or the radio cuts out randomly.
Might it be that the car battery ground is bad?
A bad battery ground can cause intermittent behavior of a car’s electrical system and unfortunately, so can other faults too.
This post looks at signs you can expect if the car battery ground is bad and what you can both test and fix it.
Signs of a Bad Battery Ground Connection
Unfortunately, the signs of a bad battery ground are not restrict to ground faults only and can be caused by other faults as well. Probably, the surest way to tell is to conduct a voltage drop test.
That being said, the symptoms below can point to a bad battery ground connection.
#1. Car Battery not charging fully. The car battery may appear to drain faster than expected because it is not charging fully.
A bad battery ground increases the wire resistance that then restricts how much current is available to charge the battery slowing down the charging process.
That being said, if the car battery is not charging fully, it might as well be that the battery or alternator is faulty.
#2. Car struggles to or fails to start yet the battery is charged. The car may crank longer than usual before turning over or just click when the ignition is switched on.
These symptoms are not limited to bad grounds and maybe also due to a faulty starter, low battery voltage, or a loose starter wire connection.
#3. Repeated alternator failures. If the battery ground is bad, you can end up with repeated alternator failures.
An alternator runs harder and longer than it should with a bad battery ground connection because of the voltage drop.
So, if should the alternators be failing sooner than expected, it could be an issue with the ground connection. Conduct a voltage drop test to confirm if this is indeed an issue.
#4. Your electricals can fail to work or work intermittently. For example, the car radio may work only sometimes, at random or the car’s headlights may flicker.
Confirm that the battery ground connection is solid, clean and firmly connection.
#5. If the battery ground cable is frayed, physically damaged or the mounting posts are rusty or corroded on either the battery post negative or where the cable is mounted on the car chassis.
Bad Battery Ground? What Test you Can Do?
You can conduct a voltage drop test to check if the battery ground connection is good or not.
What you need: Good quality multimeter, set to read DC volts.
How to test the Negative ground circuit for voltage drops
- Start the car engine. Place the black probe of the multimeter on a known ground connection for the car such as a stud on the car’s metal chassis.
- Next, connect the red meter probe to the battery post negative terminal. The voltage reading should not exceed 0.2V. If higher, confirm that the connections are clean and firm connections.
- While keeping the black probe of the multimeter connected to the chassis, next, connect the red meter probe to the car’s engine block. The voltage reading should not exceed 0.2V. If higher, confirm that the connections are clean and firm connections.
If the voltage drop is higher than 0.2V with either the car chassis or engine block even after confirming the cable connections, then there is probably a broken or damaged cable connection that you need to identify and replace for a good ground connection.
How to Fix a Bad Battery Ground
Inspect the battery ground cable connections on the battery negative and the ground post on the car chassis for rust, damaged cables, corrosion, or if the mounting post has been painted over.
If painted over (after a spray job on the car), sand the mounting bolt using sand paper to expose the underlying metal for a good ground connection.
Replace any damaged cables with wires of the same color and gauge. If there is corrosion, pour a mixture of baking soda in water over the corroded battery terminal and use a wire brush to scrape away the corrosion. You can also use a battery cleaner spray to remove the corrosion.
#1. Can a Bad Ground Cause a Car Not to Start?
Yes, a bad ground connection can make a car to fail to start because of the voltage drop caused that limits how much current is available to the starter.
#2. Can a Bad Ground Cause a Car to Stall?
Yes, a bad ground connection can cause a car to stall. If for example, the alternator has a bad ground connection, this then affects how much power is available to the car’s electrical system.
Without enough alternator power, the car’s electrical system then depends on the battery which causes the car engine to die when the battery charge runs out.
Common signs that a car has a bad battery ground include failure to charge fully, the car can struggle to start or fail to start and in some cases the alternators can fail repeatedly.
Note: These signs are not conclusive in themselves as they can be caused by other faults too. Therefore, conduct a voltage test to confirm if a battery ground is good or otherwise.