What Drains a Car Battery? Don’t Blame Your GPS Tracker

When fleet vehicles sit around unused, they can suffer from battery drain. Your team members might be finding out the hard way…when those vehicles’ batteries are dead.

So what drains a car battery? Good news: Your GPS tracking units are not to blame. Let’s look at some of the common reasons this can happen.

What Typically Drains Car, Truck, and Vehicle Batteries?

There’s no shortage of causes for battery drain – also known as parasitic drain – for your truck, vehicle, or car battery.

But some of those involve wear and tear. That’s entirely different from a vehicle parked in good condition that just refuses to start a few months later.

Chances are, it’s not anything like a bad alternator, battery terminals, corrosion, or faulty battery cables – those should be further down the list of possible culprits.

When vehicles sit, the battery is still powering things like the radio, clock, alarm, and other systems; newer vehicles have even more electronics that require energy.

Starting the vehicle and driving recharges the battery, so these electron-hungry systems don’t present a problem. Vehicles that sit for extended periods, though, don’t get to recharge. Factor in hot weather if the vehicles are sitting all summer (extreme temperatures reduce battery life in your charging system, as any hot-weather driver will tell you) and you have a recipe for dead batteries.

What’s the Best Way to Prevent Dead Batteries and Vehicle/Car Battery Drains?

 There are a few different methods to keep your idle vehicles’ batteries charged and ready.


  • Disconnect the batteries – This is a sure way to prevent electrical systems from guzzling battery power. There’s a downside, though: Your employees will have to reset the clocks and radios. It could also be a time-consuming operation. Battery disconnect switches are also an option, which could be added during a vehicle’s next scheduled maintenance.
  • Start and run the engines weekly – This is a difficult proposition. Many businesses are still short of on-site staff members, and this could take a lot of time. Simply starting is better than leaving the vehicles sit. But driving vehicles does a far better job restoring batteries’ state of charge and lifespan, and reduces the times you have to jumpstart vehicles.
  • Keep your fleet’s batteries charged – There are a few other ways to keep batteries charged. If you have the staff and time (and who has all the employees and time they’d like?), your team can charge the vehicles monthly. There’s also the more-efficient option of using a trickle charger. That also comes with a caveat: Some trickle chargers don’t turn off by themselves, which means you could wind up overcharging your batteries. You’d also need to find outlets to plug them all in, which could be challenging. An alternative would be using solar trickle chargers as a battery charger, which would provide power without raising your utility bill.
  • Set up a low battery voltage alert – More than 50% of commercial and government fleets are already using a solution that might help stop dead batteries: their GPS tracking devices. Many GPS trackers can alert management of failing batteries. GPS Insight clients can set up a report that alerts them if a vehicle’s battery drops below 11.9 volts for 30 minutes or more.
Blog Dont Blame Your GPS Tracker for Your Fleets Battery Drain

Prevent parasitic drain on your battery


Feel like you’ve done all the rest, and it’s not enough? There are additional ways to prevent parasitic drain. Take the time to:


  • Check the alternator: Make sure the alternator is working, since it’s charging the vehicle battery while your engine is running.
  • Monitor parasitic drain: Check any parasitic drain from the electrical system, since it can drain the battery even when the vehicle is not in use. Use a multimeter to measure the parasitic draw on the battery when you’re not using it. If you detect excessive draw, find the electrical components causing it and address the issue.
  • Maintain battery connections: Clean and secure the battery terminals and connections to prevent corrosion.
  • Inspect the charging system: Inspect the charging system components, like the alternator diode, fuses, tensioners, and battery cables, to find and fix any faults.
  • Think about extreme temperatures: Extreme temperatures can affect battery performance, so park the car in shaded areas during hot weather and use a block heater in cold weather.
  • Turn off interior lights: Make sure interior lights, including glove box lights, are turned off when not needed to prevent unneeded battery drain.
  • Maintain a healthy battery: Keep the battery in good condition by regularly checking its charge level, using a battery charger if needed, and replacing it when necessary due to old age or defects. Plus, an old battery may be more prone to drain and may require replacement. Keep your eye on the lifespan of the battery and consider replacing it when necessary.
  • Disable security alarm: Turn off the security alarm system in places you don’t need it, since excessive use of the security alarm can drain the battery over time.
  • Maintain battery connections: Clean and secure battery connections, including the battery terminals and negative cable, to prevent buildup. This reduces the risk of power loss and maintains the battery’s performance.
  • Maintain a charged battery: Make sure the battery is regularly charged to a full state. If the vehicle is not used frequently, consider using a battery maintainer or charger to keep it at optimal charge levels.
  • Address electrical problems promptly: If you notice any electrical problems, such as flickering lights or intermittent power issues, get them diagnosed and repaired as soon as possible. These issues can lead to increased battery drain and other potential complications.

Battery Drain? It’s Not Just Your GPS Tracker

With more than 50% of fleet vehicles using GPS trackers, it’s easy to see how fleet managers might think of all the potential sources of battery drain. Understandably, they might think the GPS tracker might be at fault.

The fact is, though, that any modern vehicle sitting for a month or more will likely experience battery drain, regardless of whether it’s equipped with a GPS tracker. Radios, clocks, alarms, and GPS trackers all pull energy from the battery, ranging from 1 mAh for a clock to as much as 20 mAh hours for a GPS unit in sleep mode (all of these numbers vary by the vehicle type and GPS unit).

A GPS tracker may draw more current — but without preventative measures, a vehicle without one will still drain its battery over time.

We recommend deciding which of these solutions makes the most sense for your fleet.

Coming up with a plan to care for vehicles that sit for a long time unused is a smart plan to make sure they’re ready to go when you need them.

Take your pick! By using preventive measures like these, you can reduce the risk of vehicle battery drain and keep a reliable power source for your vehicle’s electrical systems.

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