Hi everyone,
I have a 2013 G37X with 68K miles on it. I have a 1.5 year old Interstate battery in it which has been working just fine.
I’ve noticed the car has been having a bit of a slower start lately. Also, the other day I noticed the interior light would dim when I would accelerate the car quickly. I had never noticed this and honestly my other Infiniti Q50 does not do the same thing. I took the car for an alignment and asked the guys to check the battery for me and I was told it was good (not too confident in them though). I’ll be checking it myself just to make sure but I’m a little worried it has something to do with a bad alternator since it’s been doing the dimming thing once the car is actually running.

Has anyone ever ran into something similar?
Thanks!

 

If the interior lights are dimming with the vehicle running, and the battery is good, the likely culprit is a failing alternator. Get a multimeter and confirm it easily yourself. A good battery will show in the mid-12 to 12.7 volts range. Once the vehicle is running, the voltage should jump to the mid to upper 13 volts range which indicates the alternator is charging the battery.

Last year my sister's Accord's dash lights were flickering on start up, drove less than a mile and the car's dash lights were flickering like mad. A few seconds later, the engine just shut down. Installed a new alternator and the 12 year Accord has had no problems since.

UCLAg37

 

Have you checked water level in OEM battery. They require cells to be filled with distilled water. If cells are low it can cause cells to go bad or have weak charge

 

Don't just check the voltage at the battery terminals. Also test the voltage drop from the negative battery terminal to the body ground wire attach point. When the starter rpm's drop noticeably it may be due to the voltage drop across the negative ground wire. The voltage at the ECU will also then be too low to provide accurate sensor references and operating levels. Check out my year-long process and disaster around the ground wire attach.

 

Also check the multiple grounding straps