Have any of you determined how long you can leave your car in the garage without a battery maintainer attached? The reason I ask is twofold. First, since I rigged up my trickle charger I have noticed that after a couple of days off the charger, my charger starts earlier in the charge cycle than it does/did with my other cars. Yes, I fully charged the battery before making this determination. Second, we leave for a couple of weeks at a time and I found that previous cars could go 3 or 4 weeks without needed a charger hooked up.
Thanks,
Larry

 

I left my new V6 for three weeks in the garage and it started just fine. I just bought a battery tender plus 3 Amp and hooked it up. After four hours, it still wasn't at 80% charge. Took overnight to fully charge. I do lots of short trips and the battery must have been really low but the car operated just fine. I'm going to charge it up every week now.

 

my car sat a couple of stretches for 2 - 2.5 weeks while on vacation without issues.

 

Hi Larry ,
I was interested in this question two years ago so I measured quiescent current on my car.
The result was that standby current consumption is definitely less then 20mA .
Assuming your 90Ah battery is fully charged when you store your car and you accept to
go down to half of the stored capacity you can go for approx. 3 month .
But be careful . If you unlock/lock the car with your key , a lot of electronic devices "wake up"
and current consumption increases dramatically . Current consumption remains high after locking
the car for some minutes until all devices are shut down again .
So opening / closing the car several times during storage will noticeable shorten the calculated period .
Furthermore I recognized that the cars battery management system doesn't charge the battery to its
full capacity during normal use . Thats another drawback predicting storage time .
Hence I always charge my battery before I put my car in storage and recharge it every 4 weeks for about 12h
using a 3.6A ctek charger . Works well since 2.5 years .
regards
Ulrich

 

Thanks for the quick replies. I found out the hard way that modern cars drain the battery fast when stored, although 2 weeks was never a problem, 3 weeks was. I also found out, the hard way, that storing the key-less entry key within range of the car, as in on the mud room wall, kills the battery over a short time. The car looks for the key and talks to it. I have been told that the newest cars do not do this if locked but I won't find that out since I no longer hang the car keys on that wall.
What I want to avoid is having to leave the battery maintainer plugged in while I am away on a trip. I had a Battery Tender brand fry on me once. Popped the circuit breaker and did not hurt the car, but I have used CTEK since then.
Larry

 

My car has been in winter storage since mid October. It stays locked in a garage with the keys in "safe" distance from the car. I use a CTEK charger every 6 weeks, and it only takes aprox 5-7 hours to get it fully charged again each time.

So no problems what so ever here.