I have the exact same issue! I've had the car for 2 weeks now. The stop/start has not worked since day 1. No fault codes, and it has been driving absolutely fine. Took it into the shop today, and they said they think it has a bad alternator that is not fully charging the battery. Makes sense, but it doesn't make sense that I would be able to drive the car for 2 weeks if the alternator wasn't charging the battery all the way. I'm supposed to take a 350 mile trip in 3 days and they're telling me that it will be no issue to take the car back and make the trip, and when they get a new alternator in, just bring it back into the shop. But, if it really is the alternator, I don't want to risk being stranded on the side of the road!

 

Are you guys wearing your seatbelts, and making sure your hoods are securely closed on both sides?

 

Yep, always wear my seat belt and I did check the hood!

 

not experiencing that on mine - it's been left for up to 16 days too and powered up like it was left the day before. Do you have an alarm? That's been known to drain? Maybe a crappy battery. I know they replaced my ford one after about 6 months. I'd keep an eye on it.

 

I have had the battery completely dead twice. First time I assumed that it was because I left my radar detector plugged in. Had the car towed to the dealership and they replaced the battery as I assume they thought it was faulty. Second time it happened I had 11.2 AMPS left in the battery after letting it sit for four days. I had to jump the car using cables to the underhood boost points plus a portable unit connected straight to the battery in the trunk.

I drove it for 35 mins to recharge battery before dropping it at the shop. They took a deeper dive and diagnosed it for a faulty fuse in the fuse box in under two hours. They did a load test and found that it as drawing 0.6 volts (or AMPS?? I'm not sure), which is above the normal range of 0.25. No additional load when radar detector plugged in. $0.15 fuse has seemingly fixed the problem.

 

Battery capacity is rated in Amp-hours. The resting voltage is a poor indication of the state of charge of a battery, but when it is much lower than the nominal 12.6 Volts, it is a sure sign that the battery is not charged. Perhaps you meant that the battery was only producing 11.2 Volts?

Heavy discharge (or overcharging) of a battery shortens its usable life. It wouldn't hurt to ask for a replacement battery under warranty, given that the battery was not getting charged properly due to a warranty related fuse issue (I presume you did not blow the fuse during your radar detector installation).

0.25Amps is a high "turned off" current and 0.6 Amps is excessive. The battery is rated 95Amp-Hours, meaning that after 15 days of 0.25 Amps of draw it will be dead (95Amp-hours)/(0.25Amps*24Hours/Day) = 15 Days. To avoid reducing the battery life expectancy it should not be discharged more than 50%, or 7 days at 0.25 Amps draw (I assume a deep cycle battery). However like your computer, the car starts putting things in "sleep mode" after a timeout, so that the power draw should decrease over time if the car is simply sitting. I am not certain of the timeout period(s) or the expected long term current draw, but I suspect that the 0.6Amp figure may be related to your technician not waiting long enough for some short term timeout after "disturbing the car" before making the measurement.

 

hi all, thank you for your insights. I am going to be going in for a deeper diagnosis at the dealer soon. I know that these stop-start systems need all parameters to be met including just a small tolerance on battery voltage. We've had subzero temperatures here and the car starts just fine without any hesitation. So the battery is not draining significantly overnight. Figure it must be a fuse or a misbehaving sensor or something else that's causing a minor battery drain. Will update once I get to the bottom of this. Thanks agan!

 

Simply storing your fob too close to the car can cause increased battery drain. For example, tossing it onto a bench next to the car in the garage, leaving it on a table next to the garage door, or storing it in a bedroom that is adjacent to the garage. Since a product is available to thieves to make the fob appear to be closer to the car than it actually is, it may be a good idea to store the fob in a closed tin can or other metal container. It's too bad that the fob does not have an "off" switch. For that matter, it is too bad the car does not have a proper off switch.

Putting a battery disconnect on the battery must be done with great caution since if the battery is disconnected and then the trunk is closed you may find that there is no way to open the trunk to reconnect the battery.

 

Sorry I can't get my mind around a fuse causing more battery drain, a fuse's job is to open up if the current passing thru is too high (it does not draw any current itself). So if the fuse opened some circuit would no longer work. If the fuse had a bad connection the circuit would work intermittently and or heat up the connection causing burning out the connection (if it's a hi current circuit ), still no additional current. If the burning causes a short to ground or to other connection more than a fuse would have to be replaced (fuse box, wiring harness, possible fire).

 

They finally figured it out. It was a battery power sensor that was acting up sporadically. It happened to show that the battery was only 70percent charged when it was fully charged. No battery drain in reality. This sensor was causing the start stop to deactivate. After sensor was replaced, start stop working again!

 

I had battery drain issues until I figured out that the keys interact with the car all the time it is within close proximity.. Since I have begun to store them on the other side of the house from the garage it no longer is a problem...may be the issue you are experiencing??

 

Hi all, My start-stop stopped working a few weeks ago. I am probably one of the few on the forum who actually likes the feature I took it in. Service came back saying that there were no fault codes but battery charge was a little bit low. They charged the battery up, and start-stop worked for a few hours and then stopped working again. I don't have anything connected that could drain the battery, and do a lot of Hwy driving so the battery should be recharging. Anyone experience similar issues - battery drain or start-stop not functioning. Thanks!

its a good idea for theft-deterence, battery charge and care of key fob (not to mention decreased chance of activating the panic function) to use a 'faraday pouch' to store your key fob in.
I use one that has an unprotected compartment for when fob is in use and a shielded compartment for rest time. they are inexpensive insurance

'17 ti sport, siverstone and cf

 

Thanks for the Faraday shield comment. Yes, absolutely something everyone should do. My issue was related to the stock battery which just didn't cut it. Had to get it replaced and it holds the charge better. They should've gone with two batteries with one specifically for start stop like some other manufacturers, but then you have the additional weight.

 

Hi all, My start-stop stopped working a few weeks ago. I am probably one of the few on the forum who actually likes the feature I took it in. Service came back saying that there were no fault codes but battery charge was a little bit low. They charged the battery up, and start-stop worked for a few hours and then stopped working again. I don't have anything connected that could drain the battery, and do a lot of Hwy driving so the battery should be recharging. Anyone experience similar issues - battery drain or start-stop not functioning. Thanks!

I have been dealing with the battery issue for three years now including buying two batteries. Now the rear window defrost will not work and the only answer I get from the dealer is to put a battery minder on it. Ironic my 12-year-old Lexus gets driven once a month and not a problem. My Guila every day and battery health is at 30%. This is a safety issue in the winter when your window freezes over and you can't see out of the back of the car. If everyone complains to NHSTA ALFA ROMEO will have to do something about it besides tell you to put a battery charger on your car every night.