What Will Happen If Your Battery Drops to 9v When Cranking?

The starter motor depends on a high voltage (12-14v) to turn over the engine. Thus, if your car battery reads 9 volts when cranking, the car may not start, the battery power decreases, and it isn’t providing as much energy as it should due to a lack of available electrical current. The starter motor may also get damaged if you continue trying to crank the engine with a low battery voltage over time.

It’s always a good idea to keep your car battery fully charged or at least maintained above 50% charge. You can do this by driving your car regularly, checking the gauge, or using a trickle charger. And if you’re ever in a situation where you need to jumpstart your car, try to find another vehicle with a healthy battery with a similar voltage rating.

What should battery voltage drop when starting?

The voltage drop indicates that the electrical current is flowing from the engine through various circuits to generate power for lighting, powering interior accessories, and moving parts of the vehicle’s suspension or brakes. The lower this number, the more efficiently your car runs, and if you’ve recently been driving on less than fully charged batteries.

When you first start your car, the battery should have a voltage of about 12 volts. If your battery voltage drops to below nine volts, try the following suggestions:

  • Be sure all accessories are turned off or unplugged before starting the engine; turn headlights and heater on for about 30 seconds with the key in the ignition before trying to start the engine (this will consume some power from the battery). You can also open the door to do this.
  • Check the battery connections and terminals for corrosion or loose wires; clean if necessary before attempting to start.
  • If there is no visible problem with your vehicle’s charging system, you may need to drive around for about 15-20 minutes to recharge batteries enough that they can turn over the engine again.

What causes voltage drop when cranking?

There are a few potential causes of voltage drop while cranking. The most common is the alternator not producing enough voltage to meet the needs of all components in use at once, such as lights and other electrical accessories.

Low-output batteries can also cause this problem, as it’s hard for an engine to turn over without enough power from an electric motor or starter battery.

If your car has been sitting for a long time without being used, there may be corrosion on wires that need to be cleaned before they can adequately conduct electricity.

Finally, if you’ve replaced one battery with another, but neither is fully charged yet (or ever will be), you’ll have voltage drop problems.

To fix all causes of voltage drop when cranking, you need to distinguish which components are drawing power and replace or repair anything that needs replacing or repairing. You might also need to upgrade your alternator.

If you’re not comfortable doing this kind of work yourself, it’s best to take your car to a mechanic and have them diagnose the problem for you. Once they know what’s causing the voltage drop, they’ll be able to provide a solution that will get your car up and running again.

Are 9 volts enough to start a car?

A car battery typically needs 12-14 volts to start, and the voltage from a 9-volt battery won’t get the engine going. A car battery with a reading of 9 volts is considered low, indicating that the battery is weak. This may cause the car to stall when trying to start it. At this point, the battery should be replaced with a new one before any other road trip, or long drive is attempted.

What voltage drop is too low while cranking the engine?

A low voltage drop can indicate a weak or failing battery, a bad alternator, or a problem with the electrical system. If the voltage drop is too low, it can prevent the engine from starting or result in poor performance. Ideally, the voltage drop should not fall below about 12.0 volts for more than a fraction of a second when cranking or starting your engine, and it shouldn’t stay there once you have activated the engine.


The battery is a device used to store energy that supplies electrical power to run your vehicle’s systems while driving and crank the engine. A low voltage drop while driving can result in stalling or a complete loss of power, causing a range of issues.

Scheduling a regular appointment with your mechanic is the best way to stay updated on the health of your battery and electrical system. This way, they can check the health of your battery and ensure everything is running smoothly. They will also be able to fix any potential problems before they cause an issue down the road, thus keeping your car protected, and allowing you to avoid an unexpected breakdown.

About the author, Phil Borges

Phil Borges is a battery aficionado. He's written extensively about batteries, and he loves nothing more than discussing the latest innovations in the industry. He has a deep understanding of how batteries work, and he's always on the lookout for new ways to improve their performance.