Can You Drive Your Car With a Failed Auxiliary Battery?

by Phil Borges // in Car

You may have noticed that your car battery light just came on. It’s a sign that you need to replace it soon, but what if the auxiliary battery is also failing? The response to this question is not as clear-cut as you might think, but there are a few ways to figure out whether or not your car can still function with a failed auxiliary battery. The good news is that many cars can still be driven with a failed auxiliary battery – for how long depends on the type of car and its engine size. Read on to find out more.

Can you drive your car with a failed auxiliary battery?

Yes and no are the answers. In general, it’s not a brilliant idea to drive when something about the car doesn’t work, even if it isn’t serious. You don’t know how the problem will affect other parts of the vehicle or your safety.

If your car’s make and model is equipped with an auxiliary battery and is failing, this should not be an excuse to just ignore the situation for too long. Sooner or later, it will fail completely.

The auxiliary battery is a secondary backup power source that can be used to start the engine in case of main battery failure. Its main responsibility is to run and power the vehicle’s additional accessories such as starter and lights. If something goes wrong with the main battery, there is a backup auxiliary battery that will kick in and keep the car running. This is not a complex system to manage, but nonetheless, it requires some attention, maintenance, and replacement at regular intervals of time for optimal performance.

If your auxiliary battery begins showing signs of something wrong with it (it can be slow cranking or dimming lights), you should immediately replace it before more damage is done to the car. If you ignore it, you risk further damage and even more inconvenience if your main battery fails for good and does not give enough power to start your vehicle’s engine.

How would you know if your car has an auxiliary battery?

If you are not sure or indefinite if your car has an auxiliary battery or not, you can check your owner’s manual for this information. If the car is a used one and it does not have an owner’s manual, some cars do come with a sticker on the inside of the driver door panel that provides descriptions about every part in the vehicle, including if there is an auxiliary battery installed.

Another option is to check the internet. There are many websites today with information on cars. You can simply search for your car’s make, model, and year to see whether it has an auxiliary battery or not. Or better yet, you can visit a local auto parts store or car dealership to seek for a more concrete answer. This way, you can also get to know more about the car’s auxiliary battery by asking for advice from professionals.

What are bad auxiliary battery symptoms?

If you have a built-in auxiliary battery in your car, it is always best that you check for common symptoms of bad auxiliary battery to watch out for. Auxiliary batteries can also fail completely without any warning signs at all.

However, if you look more closely to your vehicle’s dashboard, you will notice an error that indicates a faulty auxiliary battery. In certain automobiles, you may observe a battery symbol on the dashboard when the auxiliary battery malfunctions. Some may have liquid leaking from the battery or a faulty auxiliary battery that is bulging.

Car auxiliary battery malfunction is not an uncommon problem. In fact, it is one of the most common problems that car owners face. Maintaining it and having it checked regularly will have a better chance of having it repaired or replaced before serious damage is caused.


Car issues can be avoided by maintaining the car in good condition. But sometimes, even if you keep your vehicle well and take care of it with utmost patience, issues still arise that can really put you in trouble on the road.

Your auxiliary battery is one such example. It’s an expensive part to replace or repair; hence taking proper preventive measures is necessary.

In order to avoid any serious problems, it is important that you do not drive your vehicle for over 100 km once you begin experiencing issues with the Auxiliary battery. The reason is that this type of power doesn’t come from within and so has no effect on driving functionality or performance. However, when something has gone wrong while you are out there, it will certainly cause additional problems in the future if not handled carefully.

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.