Infiniti Battery Keeps Dying Overnight: Causes and Solutions
There’s a sinking feeling that comes from walking out to your Infiniti on a cold morning, pressing the push-button start, and hearing nothing but a weak click from under the hood.
Your battery died overnight. You’re late for work. And you’re wondering what went wrong. If this sounds familiar, you’re not alone. Battery drain issues are one of the most common complaints among Infiniti owners, and they happen across multiple models—from the Q50 to the QX60.
The good news? Most of the time, the cause is something you can diagnose and fix yourself. Let’s walk through the most common reasons your Infiniti battery keeps dying and exactly what to do about it.
The Simple Things to Check First
Before you dive into complex diagnostics, rule out the obvious causes:
- Did you leave something on? Check that your interior lights, trunk light, and headlights are completely off. A stuck trunk light or glove box light can drain a battery overnight .
- Is your battery simply old? If your battery is more than three or four years old, it may have lost its ability to hold a charge. A battery that starts the car fine one day can be completely dead the next once it reaches the end of its life .
- Are you taking mostly short trips? Short trips don’t give your alternator enough time to recharge the battery after starting the engine. Over time, this slowly drains your battery .
Parasitic Drain: The Hidden Culprit
If you’ve ruled out the simple stuff, your battery is likely suffering from a parasitic drain. This means something in your vehicle is drawing power even when the car is turned off. A normal Infiniti should draw about 0.05 amps (50 milliamps) when parked. If you’re seeing 0.06 amps or higher, something is pulling too much power .
Several common issues can cause parasitic drain in Infinitis:
Aftermarket Accessories
This is one of the most frequent causes. Dash cams, remote start systems, and aftermarket stereo equipment can continue drawing power even after the car is turned off. One Infiniti EX owner discovered their dashcam was the culprit—it was supposed to shut off with the ignition, but a module failure kept it running . Another owner installed a dashcam that blew a fuse, and after replacing it, their battery drained in just one night .
What to do: Disconnect any aftermarket accessories one at a time and see if the drain stops. If you can’t find the issue, a mechanic can test for draws across different circuits.
The Infiniti “Tow Battery” Fuse
One QX60 owner discovered a parasitic drain of 200-250 milliamps coming from a 30A fuse labeled “Tow Bat.” The owner had no towing equipment installed at all, yet pulling that fuse dropped the draw to a normal 70 milliamps . This suggests the towing wiring harness or its relay may be defective or causing a short.
What to do: Check your fuse panel for a “Tow Bat” fuse. If you don’t have towing equipment, try pulling it and see if your battery drain stops.
Welcome Lights and Dome Lights
Some Infiniti FX35 owners have reported that welcome lights and dome lights turn on about 10 minutes after shutting the car off. The dealer was unable to fix the issue, and owners ended up replacing the battery every 12 to 18 months . One owner installed a battery shutoff switch as a workaround.
What to do: If you notice lights coming on unexpectedly, have a mechanic check for a faulty light control module or body control module (BCM).
Failing Body Control Module (BCM)
The BCM controls many of your Infiniti’s electrical functions. If water leaks into the cabin and damages the BCM, it can cause all sorts of electrical glitches, including battery drain. One owner discovered their 2018 Q50’s battery was draining because the locks were automatically locking all day long. A water leak from the sunroof drain had damaged the BCM .
What to do: If you suspect BCM issues, have your mechanic check for moisture around the BCM and test its functionality.
Stuck Relay or Faulty Switch
A faulty relay can keep a circuit active even when the car is off. One Infiniti Q45 owner traced a 235-milliampere draw to a stuck relay . Other owners have reported that faulty door lock or trunk lock switches can cause continuous battery drain .
What to do: A mechanic can test relays and switches by pulling fuses one at a time to isolate the circuit causing the draw.
Battery Drain in Specific Infiniti Models
Infiniti Q50
Multiple Q50 owners have reported battery drain issues. One owner with a 2014 Q50 hybrid found that after the dealer installed a new battery, the car would drain in under five hours . A 2020 Q50 owner had to jump-start their car every weekend. The dealer eventually diagnosed the issue as a parasitic draw causing the battery to drain overnight .
Infiniti QX60
The 2022 QX60 has been subject to a legal investigation over electrical issues, with owners reporting battery drains and dashboard malfunctions . QX60 owners have also identified parasitic draws from towing-related fuses and other circuits . One owner solved their QX60 drain problem by installing a remote-controlled battery disconnect switch for about $30 .
Infiniti QX50
QX50 owners have reported battery drain and stalling issues even after having the battery recharged by a dealer. Some owners noted that leaving seat warmers or coolers on can exacerbate the drain .
How to Diagnose a Parasitic Drain Yourself
If you’re handy with a multimeter, you can diagnose a parasitic drain:
- Turn off your car and remove the key. Wait at least 15 minutes for all systems to go to sleep.
- Disconnect the negative battery cable and connect a multimeter in series between the negative terminal and the negative cable.
- Check the reading. Normal draw is about 0.05 amps (50 milliamps). Anything higher than 0.06 amps indicates a problem .
- Pull fuses one at a time while watching the multimeter reading. When the draw drops significantly, you’ve found the circuit causing the problem .
“If a parasitic draw occurs, a new battery won’t solve this original problem—it will just take a little longer until it’s empty again. If the draw is higher than normal, check fuse after fuse and measure the difference.” — Infiniti Q50 Forum
Always disconnect the negative battery cable first and reconnect it last to avoid sparks and potential short circuits.
Quick Fixes vs. Long-Term Solutions
| Solution | Pros | Cons |
|---|---|---|
| Battery disconnect switch ($30) | Inexpensive, easy to install | Resets memory settings, doesn’t fix root cause |
| Battery tender | Keeps battery charged when parked | Requires plugging in, doesn’t fix root cause |
| Professional diagnosis | Finds and fixes the actual problem | More expensive upfront |
Frequently Asked Questions
Why does my Infiniti battery drain overnight?
The most common causes are a parasitic drain from an aftermarket accessory, a faulty relay or switch, a damaged Body Control Module (BCM), or simply an old battery that can’t hold a charge .
How do I find a parasitic draw on my Infiniti?
Use a multimeter connected between the negative battery terminal and cable. Wait 15 minutes for systems to sleep. Pull fuses one by one until the draw drops—that identifies the circuit causing the issue .
Can a dash cam drain my Infiniti battery overnight?
Yes. If your dashcam doesn’t shut off completely with the ignition, it can draw power all night. Check that it’s wired correctly or disconnect it to see if the drain stops .
What should I do if my new Infiniti battery keeps dying?
A new battery won’t solve a parasitic draw—it will just take longer to drain. Get a professional diagnosis to find the root cause. Check for aftermarket accessories, faulty relays, and water damage to the BCM .
Does the Infiniti QX60 have known battery drain issues?
Yes. 2022 QX60 models have been the subject of legal investigations over battery drain and electrical issues. Owners have also found parasitic draws from towing-related fuses .
How much does it cost to fix a parasitic battery drain?
A professional diagnostic typically costs $100-$200. The repair cost depends on the cause—a faulty relay or switch is inexpensive, while a BCM replacement can cost $800 or more.
References:
- Carly – Infiniti EX Battery Drain Diagnosis
- Infiniti QX60 Forum – Battery Drain and Tow Fuse
- Infiniti Q50 Forum – BCM Water Damage and Battery Drain
- Infiniti Q50 Forum – Parasitic Draw Diagnosis
- Shub & Johns – 2022 QX60 Battery Drain Investigation
- Infiniticity – Battery Drain Causes
Have you dealt with a battery drain issue in your Infiniti? What ended up being the cause? Share your experience in the comments below.
