My BMW 2002 530i’s battery was low and I needed to jump her in order to start. I charged it, drove for 30 minutes, took a break, then she wouldn’t start again.
Then I did something realllly, reallllly stoopid.
I crossed the neg/pos jumper cables because I was tired and not paying attention.
Then commenced a spectacular show of smoke, totally melted cables, neighbor running over with extinguisher and then knocking the cables off the batteries.
The Jeep is fine, she turned right over and drives with no issues. The BMW is totally dead.
Is there any chance that a battery replacement will rescue the car? Is this the end? I’m so pissed at myself! :(:(:(:(
I did a quick look online. I am NOT an expert. It could be anything from fuses to the alternator, with some extra flavors of wiring badness thrown in if you’re extra lucky. It doesn’t sound like your car is necessarily toast. It sounds like (from your description) you need a new battery anyway. Take it to the dealer and get it diagnosed… Hopefully a new battery and alternator will be the extent of it. Good luck.
I’ve never done this, so don’t know. The battery is surely toast, but if the ignition was off on the BMW, hopefully not too much upstream got wrecked. Whole lot of potential for disappointment, however.
Keep us posted.
One of my BMW’s wouldn’t start earlier this week. Corroded positive cable, turns out.
I would guess most of the charge would flow along the jumper cables as the batteries tried to discharge each other. I wouldn’t be surprised if the Jeep’s battery is damaged. Even if it works now, it may fail sooner than it otherwise would have. You should probably offer to replace it just as a good-faith measure. Or at least tell the owner to have the battery checked out. Most auto part stores will do it for you.
I would guess your car would be okay, but BMW’s do have lots of delicate electronics. Try a new battery and see what happens.
As a side note, whenever my battery fails and I get a jump, the first place I drive is to the auto parts store. It seems once a battery is drained, it seems to be on its last legs. I have the store test it out and get a new one if necessary.
Another thing you could try–take your battery to an auto parts store and see if they can charge it up. Then you could see if it can start your car without having to buy a new battery.
A hard lesson that may cost you some bucks. On the one hand, dollars can be replaced. On the other hand, your life cannot. Keep the perspective. Good luck.
If you do not know how to use a multimeter, then take it to a mechanic.
Replace any damaged cables.
Alternator probably bad. May be able to charge the battery, if not, get a new one. (Use a battery charger.) BUT that battery will drain down too if the alternator is bad!
Use a multimeter the check your battery and charging system.
Hint: If you do not plug in your cell phone to recharge it, do you go and replace the battery? (Cars are charged wit the “alternator”.)
REALLY well said, Duckster! A lesson I keep learning over and over is not to do things when I’m tired. Maybe someday it will actually sink in all the way . . .
Latest report: I bought quality jumper cables and the car started right up with the Jeep* charge; the electronics are working (windows, sunroof, MIDI displays, alarm, etc). I drove her straight to the mechanic and am having the battery replaced.
Hopefully this will be the fix (with possibly the alternator). I’m on the cusp wherein I adore this car and she runs like a dream, but she is aging (144k) and I’ll need to weigh moola vs. selling her to a DIY guy (or gal).
The Jeep is mine, so I haven’t ruined anyone else’s property I was going to truck the battery in to be tested but couldn’t get the stupid terminals off and was afraid to be marooned in the car.
A few more details about what happened with the car this week. Since we’re car people, I thought this might be of interest.
-On Wednesday she wouldn’t turn over. Luckily I was at the gas station getting gas and their mechanic tapped the alternator with a hammer and it cranked right over.
-I drove directly to the indy mechanic I use, I was pretty certain it was the alternator. However, The car was throwing codes for a security system problem and no alternator problems. The alarm went off a few times while the car was there (without any obvious tilts/squirrels leaping upon, etc).
-My guy started the car several times without jumping it. When I got in the car it wouldn’t start. The guys jumped it and suggested I take car to BMW dealer for a possible security system issue. The battery did test a bit low.
-So I took her home and attempted to light her on fire
One of my theories is that someone tried to break into/leaned hard against the car when I was parked at work on Tuesday. I heard the alarm go off, but thought a falling leaf had touched it (the alarm is incredibly sensitive :)). I know the car has an engine deadlock if it senses it’s being stolen (dunno how to put it other than this). My MIDI display is a bit pixellated and I couldn’t get to the ignition lock-out code to see if it was somehow activated and needed to be re-set. However, not sure this would explain why she starts when jumped.
Batteries sometimes get wonky as they age and near the end of useful life expectancy. In some areas 5 years is pushing it. Batteries often choke the first cold snap in autumn but it’s the heat that killed them. Many people pride themselves with torturing every last electron out, but this is risky with modern computer controlled vehicles and tends to smoke alternators and other expensive gee-gaws. Normally a battery and charging system in good health will never need jump starting. Always recharge the battery as soon as possible with an AC charger and have it load tested to see if damaged. The problem, a defective battery can damage the alternator, and the reverse is also true. This is a good way to become a member of the alternator of the month club and similar associations. Jump starting is an emergency-only stunt imo, and technically fairly dangerous in fact. Battery explosions don’t happen often, but they are by no means uncommon. The amount of potential energy stored in a battery is huge. Be careful!!
Back when I lived in the northeast, I called up a tow truck when my Jeep (Comanche back then, oh Comanche how I miss thee*****) wouldn’t start one cold early winter morning. The dispatcher said he didn’t need a calendar to know when winter had arrived; he just needed to wait until he got a dozen calls about dead batteries in one morning.
Just a random dead-battery-related aside.
***** - new (new-)Wrangler-based pickups coming out in a yearish-plus!
