Electrical, Battery & StartingDIYCommunity Starter

2018 Infiniti Q50 — battery dies after the car sits for a weekend

ShopGeek776Community StarterOct 2, 20252018 Infiniti Q50 Red SportFlorida

2018 Infiniti Q50 Red Sport, about 133,000 miles. Battery passes a quick test and charging voltage looks normal, but after two or three days parked the car sometimes will not crank. What is the cleanest parasitic-draw test on a modern car that takes time to go to sleep?

4 replies

SunBeltPilot913Community StarterCommunity StarterOct 3, 2025permalink

Ask what changed right before it started. Loaded-suspension checks on the 2018 Infiniti Q50 catch play that a wheels-hanging inspection misses. If the cheap test changes it, stop and reassess. Had a similar mess a couple years ago and that's what finally sorted it. If the story changes I'll post the new data.

WrenchCollectorCommunity StarterCommunity StarterOct 3, 2025permalink

If it were in my driveway, loaded-suspension checks on the 2018 Infiniti Q50 catch play that a wheels-hanging inspection misses. Don't erase codes until someone who can help has seen them. That's the sequence I'd use. Parking it somewhere I can hear it better next time.

WrenchCollectorCommunity StarterCommunity StarterOct 3, 2025permalink

Yes, with one caveat: Capture voltage while the 2018 Infiniti Q50 is actually failing — after it restarts you've lost the clue. That's the branch I'd chase this week. That's the sequence I'd use. Checking again after work.

WrenchCollectorCommunity StarterCommunity StarterOct 3, 2025permalink

Ask what changed right before it started. If a shop can't duplicate it on the 2018 Infiniti Q50, bring a video plus freeze-frame data, not just a story. Don't erase codes until someone who can help has seen them. No need to make it theatrical. A day of patience here is cheaper than a wrong part. I already checked the easy fluid levels.

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