Skip the auto shop - Our mechanics make house calls

How Long Does an Auxiliary Battery Last?

auxiliary battery

When a dual battery system is added to a vehicle, it is usually because accessories have been added to the vehicle that are not factory-standard, and the primary battery in the vehicle does not deliver sufficient power to drive these new accessories effectively. Understand that we’re not saying you need an auxiliary battery to power, say, a phone charger or a stand-alone GPS. It’s more like if you’ve converted a cargo van into a camper, and you’ve added a fridge, microwave, entertainment system… you get the idea. In that case, it can be highly advantageous to have one battery to deal with starting your vehicle, and another to operate your accessories. That way, once you’ve reached your campsite, you don’t have to worry about drawing power from your primary battery.

So, how long will your auxiliary battery last? Properly cared for and maintained, you can expect anywhere from 18 months to 3 years of life from an auxiliary 12-volt battery. Much will depend on frequency of use, and how well the battery is protected. Rough roads can cause the cells to break down, reducing the lifespan. Allowing it to drain to less than half of its rated capacity will also reduce the life of the battery. And of course, if you are parking your vehicle for any length of time, you should use a battery maintainer.

Signs that your auxiliary battery needs to be replaced include:

  • Accessories not operating properly
  • Accessories not working at all

If you think your auxiliary battery could be failing, have it checked. A professional mechanic can test your auxiliary battery, and replace it if necessary.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...


Related questions

Q: Advice on replacing the positive battery cable on a '95 Ford Mustang GT

Yes, definitely replace the cable. It was a design flaw on those, and as they get old, they short out internally. It happens all the time. And don't just get those cheap splice kits and put it in and done....

Q: I changed th alternator I've changed all the fuses and whenever I turn on the lights the battery drains dead and the windshield wi

This may be a voltage regulator problem. As you may know the voltage regulator manages the amount of power the alternator supplies to the battery and other accessories. When this is not working correctly, the battery can be over charged...

Q: Car won't charge

Hello! Since you have replaced the battery, we will put that to the side, but we cannot ignore it. A failed charging system puts a large load on a battery and can damage a new one, so I suggest having...