Battery died over night

M_Six · #1 04-09-2010, 10:31 PM

The X5 ran fine yesterday. Last night the alarm went off for no apparent reason. Went out tonight to head out to a show and the car wouldn't start. Barely got half a crank and then it all went dead. Just got home and tried it again and it's really dead now.

Two questions:

1) Do batteries die this quickly normally?

2) Is it possible to unlock the doors with the key if the battery is completely dead or should I leave it unlocked?

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X5 Meister · #2 04-09-2010, 11:15 PM

If it's totally flat then you'll know it since your key remote won't work and you won't be able to open the trunk from the trunk handle switch. Your only entry into the car is from the driver's side door using the actual key. So go ahead and lock it, as long as you have access to the driver side lock you can get into the car.

Connect it up to a charger and see what happens after 24 hours. Or else get a jump start and go for an hour drive to charge it up. Then when you park it, connect it to the charger to top up the battery charge level.

BTW, is this the 2003 X5 and is it on it's original battery? If so 7 years is pretty darn good.

M_Six · #3 04-09-2010, 11:28 PM

Quote:

Originally Posted by X5 Meister

If it's totally flat then you'll know it since your key remote won't work and you won't be able to open the trunk from the trunk handle switch. Your only entry into the car is from the driver's side door using the actual key. So go ahead and lock it, as long as you have access to the driver side lock you can get into the car.

Connect it up to a charger and see what happens after 24 hours. Or else get a jump start and go for an hour drive to charge it up. Then when you park it, connect it to the charger to top up the battery charge level.

BTW, is this the 2003 X5 and is it on it's original battery? If so 7 years is pretty darn good.

Yeah, I have no problem if it's just an old battery. That I can replace. It's just weird that it died so quickly and with no warning. At least it was sitting in my driveway at the time.

Thanks for the reply. Was pretty sure I could get in with the key, but just wanted to check. I'll jump it tomorrow and get it to my indie. Need to get the snows off and a taillight replaced anyway.

bobby · #4 04-10-2010, 02:17 AM

battery can die without warning. it happened to me recently, one day it ran fine then the next day it died. well not completely, the remote still worked but the car won't start. long story short got new one from walmart called Maxx for $77 with 3 yrs warranty. dropped it in and the car started right up. very happy with it. i don't know about the long term quality but for that price, it cant be beat.

Penguin · #5 04-10-2010, 10:15 AM

Batteries typically do not die suddenly, but they do stop "working" suddenly.

Modern vehicles with electronics, unlike older cars, have a voltage threshold below which the electronics simply cease to work. So while the battery is dying slowly, you often do not see any symptoms until one day it won't start, e.g., if you measured the battery voltage over the past year, you would probably have seen a gradual decline.

M_Six · #6 04-13-2010, 11:01 PM

Weird turn of events on this. My indie says they charged the battery and it holds a charge no problem. He says there's nothing wrong with it and that I must have left something on to drain it over night. I'm fairly certain I left nothing on, although as I said, the alarm did go off for no apparent reason.

Should I get a second opinion on the battery? These guys are pretty good and know BMWs, but I'm still at a loss to explain the dead battery.

X5 Meister · #7 04-13-2010, 11:51 PM

Your indie can certainly be correct in that the battery might hold a charge just fine and your alternator is functioning properly as well. What might be happening is something intermittent is severely drawing current and wiping out your battery without you ever knowing it. (Did your battery charge light ever light up? My guess is that it didn't.) For some people it's a malfunctioning lock mechanism that cycles all night long. For others it's another system that keeps turning itself on, going back to sleep, and doing that continuously. It's a problem that really sucks (no pun intended). Your best bet is to give it to a good shop to spend a few days looking for the drain, but if I were a betting man I'd say it has something to do with your alarm system given the order of events that you describe. Some part of it I would bet is draining your battery big time.

Until you do that I would not lock the car using the remote any longer and use the key in the door (make sure all the other doors are locked though) so as not to engage the alarm. I'd also keep a good set of jumper cables with you at all times or a quality jump starter that is easily accessible. Don't forget that if it's completely flat you won't open the trunk. If you need to get your cables or jump starter out of the trunk then it's going to have to happen by folding down one of the back seats.

Also, when it happens again drive it immediately to the shop. I think it's one of the instances when connecting to a battery charger doesn't really help you at all since it will only mask the problem and slightly delay the inevitable.

M_Six · #8 04-14-2010, 12:07 AM

Thanks. Good advice. Jumper cables are already in the car. We're getting ready to go on a trip. Think I'll bring the wife's Honda to the airport.

toddjoh · #9 04-15-2010, 11:18 PM

buy yourself a FSR Final stage resistor. instal it yourself or have your mechanic instal it. should take him less than 30 min.

When it goes bad it will draw power and leave you stranded. We recently replaced a battery, problem continued, part store said it was the alternator so I replaced it. very pricy BTW. Still would find the car dead every few days. Changed the FSR and now one month latter no more dead battery. Part was about $70 on Amazon. $150 at dealer.

X5 Meister · #10 04-15-2010, 11:44 PM

What made you think of the FSR?

Quote:

Originally Posted by toddjoh

buy yourself a FSR Final stage resistor. instal it yourself or have your mechanic instal it. should take him less than 30 min.

When it goes bad it will draw power and leave you stranded. We recently replaced a battery, problem continued, part store said it was the alternator so I replaced it. very pricy BTW. Still would find the car dead every few days. Changed the FSR and now one month latter no more dead battery. Part was about $70 on Amazon. $150 at dealer.

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