How long does the battery last in sleep mode?

So I've twice in the past month had a dead battery due to driving the car less in winter. What the heck is up with these cars draining batteries so fast?!?!?! It's such a pain too, have to hook up another car to the post in the fuse box to pop the hood and then let it charge for a while because my mazda doesn't crank enough to actually jump it without charging it for a while. Ugh. Anyway short of a battery tender (I have one but it's a bit of a hassle), I was reading that if you lock the doors then it will go into sleep mode after a bit and not drain the battery so much. I've been parking it unlocked because it's in my garage. If I remember to lock it will the battery last more than 7-10 days like I'm getting now? Anyone know roughly how long I could expect it to last? Trying to remember to just take it for a spin once a week but I'm wondering how much spare time I'll have if I remember to lock it.

Locking the doors will put the car in sleep mode reducing the battery drain. If I recall it takes 5-7 days to enter sleep mode. Once in sleep mode you need to unlock it with the key and use your remote to deactivate the alarm before opening the door. 7-10 days seems like a very short time for your battery to go dead. You need to invest in a good charger that plugs into your cigarette lighter to make it easy. Also, if you have a wet cell battery make sure you occasionally check the cell levels.

1. Have the battery checked. You can expect only 3-5 years of optimum battery life. If older, replace it, it's real easy DIY. Did it in my 987, there's a thread. 2. Why not drive it more? I found the 987 was a good daily driver (tho if u commute in Portland, maybe not).

Investing in a good battery maintainer, used regularly during periods of vehicle none or less use, can significantly prolong the life of a battery. It pays for itself. Also, if it takes takes a period of charging time with jumper cables before the car can be started, the jumper cables wires are too small to support the required starting electrical power surge. Invest in a good set of heavy duty (small wire guage # [i.e. large wire]) jumper cables and the car will start instantly after the cables are hooked up. This is an instance of needing to go big or you don’t go home.

Or buy a booster pack for a couple of hundred bucks or less. Starts car without having to use jumper cables and if you get one with a compressor, you don't have to go to a gas station to fill tires.

I have a battery maintainer. The plug that comes with it is permanently wired to the battery and comes out through the back of the front hood. I just plug it into my maintainer and then turn on the maintainer. Works like a charm.

The battery that was in it was 1 year old. It now has a brand new battery because the first time it died a month ago I accidentally hooked the jumper cables up backwards and fried it...So now it has a brand new die hard gold gel battery in it. Like I said I think the reason it was draining so fast was because I left it unlocked which apparently causes the car to use more power in standby. So does anyone know if it's locked and in sleep mode how long would be 'normal' for it to be able to go without draining?

Its going to always drain. This problem is well known and there are probably dozens of threads on the subject. I can attest to the fact the 987 ate batteries. Read the FAQ and search on old articles. Search under 987 for battery. I, like, many just bought a maintainer and the car lived on it when possible.

I have left my 2007 CS in the garage, unlocked, for well over two weeks and it cranked strongly...but I'm in Southern California and the garage temp never gets below 50 or so. So, either your cold Oregon temperatures are having an effect, or there is something else in your car that is draining the battery (or both!). Any aftermarket items wired or plugged into the car? Cell phone charger, audio amp, radar detector?

There shouldn't be. Stock stereo system, I have a bluetooth adapter hooked up to the aux input but I rewired the power outlet in the passenger footwell to only turn on when the key is in so it is not drawing any current. I might have to get my multimeter out and try to see if something is still running. Though I guess it was a little longer than I thought since I last drove it, looking at my receipts I apparently last drove it 12/17 to go to home depot and then found the battery dead yesterday on 1/3. So 19 days. But my mazda can sit that long no problem and the Boxster has a brand new battery so I don't know... Ah well I ordered a battery tender junior and cigarette lighter adapter. Still will try to make a point to drive it weekly but it'll probably be better for the battery to keep it topped up.

I never lock my car when it's in my garage. It's 5.5 years old now, and I often leave it for weeks without a tender, and it always cranks strong. In November (for example), I was away for 3 weeks and didn't drive it for a least 1 week before my trip. It fired right up. Now that the roads are covered in salt and I know I won't drive it until we get a good rain to clean them, I have it on the tender. There are many threads about tenders. I hooked leads directly to my batter terminals. It takes me 3 seconds to hook it up now, and 3 seconds to unplug it. But your battery should not be draining so quickly.

I'm all in for a battery maintainer. I used one on my 2007 from new -- and it still had the OEM battery going strong in 2015!! I would think that cold temps might be a factor-- but in Calif, our definition of "cold" is weather that needs a light sweater..:hilarious:

I have a 987.1 and had the same issue. It has a battery in there that is roughly 5 years old. I don't drive it often, and so once every two weeks I'd have to hook it up to a battery trickle charger, dummy style. If I forgot, the battery would get quiet low, and once or twice I almost couldn't get the car to unlock. The car collection grew, the 987.1 got neglected a little more and I finally decided it was time for a good battery tender . I currently have two Cytek Mus 4.3 units in the garage. After having these on the cars, I'm a firm believer. You got to spend the time to work them up with the quick release connectors, then you have zero excuse not to use them. FYI, a battery should last roughly 5 years. With a maintainer that is always connected to the car, I've heard estimates of 10 years and more. The maintainer is the cheapest route. Otherwise you can also try a deep cycle AGM battery . I would avoid the Optima brand, as the quality has gone down hill. Odyssey is good, and another popular one is the Deka Intimidator. If you do use a AGM battery , make sure your maintainer can charge it properly. Otherwise it will fry the battery, and you will have just ruined its performance.

My toys are tucked in for the winter and all of them are on battery tenders. The motorcycle has a battery tender JR (as does my pressure washer - it's a bad *** one, 18 hp v twin!) and I went with a C-tek for the cayman (they relabel them for Porsche ) with the cigarette lighter adapter into the center console. All the little clocks and computers put a drain on batteries as well as their normal discharge over time. BUT - If the battery doesn't have enough after a week or so of sitting something isn't right. Check for crud at the terminals, then with the car running check for voltage at the battery (should be about 14), as a last check have the battery load tested. I usually do this at the parts store when I've already prepared myself to buy a new battery just to make sure...

I have also heard that the Porsche goes into sleep mode in 5-7 days. The problem with my car is that it goes into sleep mode after 20 minutes. How do I get it to stay awake for a few days?