I have noticed this winter that if I let the car sit for a few days, it will be drained of power and not be able to start the car. In a few instances, the dash may light up briefly but then freeze. All is well if I hook up my portable car starter and start the car up.

I took the car to my dealer and they said the battery did not pass testing. They said that even though the car is 9 months old, they replaced it for free--normally prorated. However, the same thing happened again today after the car sat for a week.

The only add-on power item I have is the Escort 8500 detector hardwired to the rearview with an Invisicord.

I check all interior accessory options and made sure they were off (don't they turn off when the car is off anyways?) but this still happened. Has anyone else had this happen? It didn't seem to happen during the summer. Also, when starting up, the Escort (in voltage mode) will alarm ***low voltage*** when immediately when starting the car. Once the car is running, I get about 14.2-14.3V so I think the alternator is fine.

 

I had this happen a few months ago when car sat locked in my garage for a week. Dealer said battery and charging system checked out at time. Only thing I did differently during that week was to keep the car locked in the garage. Problem has not reoccurred.

 

My G35 is not my primary car. I drive a WRX Wagon to work and for errands. Maybe this happened because it was cold and the car is often not driven for 5-7 days? Doesn't seem right though... Maybe the key detect system drains a lot of power?

 

Nope -- definitely not normal ....
Did the dealer do a complete charging system check ?? Somethings not right esp. since it happened twice ...

How cold did it get last week (when the car sat) ??

 

long many days is "few days"?
sound about right if car sits 2-3 weeks or more

 

another member on the forum had a similar problem. It turned out to be the head unit. It had a short, and would constantly drain power when the car was off.....
They replaced his head unit, and the problem was eliminated.

Make sure the dealer does a thorough test of the electrical system. Maybe your Radar install is shorted?

 

My car sits in a lot untouched for 4 weeks at a time (work 4 weeks on / 4 weeks off). And I've never had that problem. So unless there is a something draining the battery it is definitely not normal.

 

OK, thanks for the feedback. I will have the dealer check it again. It has happened 5 times this winter!!! It would happen after sitting anywhere from 3-7 days. I double checked the detector...everything looks proper. On the dealer service, they only list battery testing.

 

For the first 7 months of owning the car, I used my TL as a DD and only drove the G ~ 2-3 times a month, and i keep it in the garage locked and never had any battery problems...

 

There is a lot of discussion on this here and other G35 forums. You didn't say what year your car is but it is probably an early model. Very common on '03. Do a search on battery drain.

 

My car is a May 2007 build G35 sedan. I took it to the dealer today and they said they could find no abnormal power drain. They said 5-7 days is a long time and it *might* be normal because of the clock and what have you.

In any case, since I cannot exclude the radar detector, I will leave it unplugged and measure battery voltages daily while it sits--it seemed to be turning off completely though and I double checked that the brown/black wires on the rearview mirror were the right connections. This last episode, the battery voltage was 6V after 7 days. This past week hasn't been that cold--high's in the 30-40's.