# Battery replacement



## NickD (Jul 16, 2003)

Hey guys. This morning I awoke to a dead battery in my car. It went without any warning. I drove ~80 miles late last night, accidently left my radar detector plugged in over night and this morning it was dead.

The strange thing was when I went to start it it clicked like a normal car with a dead battery however the xenon lights were coming on while I was cranking. I got a jump start from a neighbor, however the first time I tried to start it I got the exact same results. The xenons came on and the car made the exact same noise. Then I got out of the car, checked everything, tried one more time and started right up. I just want to make 100% certain it was indeed a dead battery.

Also, where is the best place to get a battery replacement? I heard with the aftermarket batteries you need to get the vent kit as well. Any suggestions?


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## The HACK (Dec 19, 2001)

Sounds more to me like you left your headlights on and that drained the battery. Otherwise why would the Xenons fire up when you crank the engine? :dunno:


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## Kaz (Dec 21, 2001)

The HACK said:


> Sounds more to me like you left your headlights on and that drained the battery. Otherwise why would the Xenons fire up when you crank the engine? :dunno:


Auto-lights? :dunno:

Often in modern cars, accessories will appear to work fine but the battery will be too low for starting the car. This happened last month to a friend of mine with a Civic.

As for venting, I don't recall ever seeing any vent plumbing in a E46, even in my wagon where the battery is in the passenger compartment. There is a slam vent right behind the battery compartment, though.

Also, I don't know if there is an aftermarket battery out yet that is an exact fit. BMW has often relied on a lip around the bottom to hold their batteries in place and that's something most aftermarket manufacturers don't bother with.


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## The HACK (Dec 19, 2001)

Kaz said:


> Auto-lights? :dunno:


Not on a '99 328i, at least not from the factory.

Still, it takes about 2 days to drain the battery with the parking lights. The V1, if plugged into the cigarette plug, should shut off after about 45 minutes. If hardwired to accessory power, should have turned off when the key was removed.

Anyway...4-5 years seems to be the lifespan of BMW batteries unless a lot of extra tender loving care is used.


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## NickD (Jul 16, 2003)

The HACK said:


> Not on a '99 328i, at least not from the factory.
> 
> Still, it takes about 2 days to drain the battery with the parking lights. The V1, if plugged into the cigarette plug, should shut off after about 45 minutes. If hardwired to accessory power, should have turned off when the key was removed.
> 
> Anyway...4-5 years seems to be the lifespan of BMW batteries unless a lot of extra tender loving care is used.


My car does have the auto shutoff for the lights. The parking lights will stay on but not the main headlights. Perhaps something is getting left on but I checked everything and there seemed to be nothing left on.


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## The HACK (Dec 19, 2001)

NickD said:


> My car does have the auto shutoff for the lights. The parking lights will stay on but not the main headlights. Perhaps something is getting left on but I checked everything and there seemed to be nothing left on.


ALL E46es have that feature. If you turn off the key the headlight goes out. That is not what Kaz meant by "auto-lights". '02 or later with premium package comes with automatic headlights that TURN ON in low-light situations.

If you leave your headlight SWITCH turned to the "on" position the parking lights will remain on and those will sap your battery in about 2 day's time.


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## NickD (Jul 16, 2003)

The HACK said:


> ALL E46es have that feature. If you turn off the key the headlight goes out. That is not what Kaz meant by "auto-lights". '02 or later with premium package comes with automatic headlights that TURN ON in low-light situations.
> 
> If you leave your headlight SWITCH turned to the "on" position the parking lights will remain on and those will sap your battery in about 2 day's time.


My parking definitely weren't on. As I remember walking around the front of the car.

I was thinking perhaps that the xenon lights powering up when I was trying to start the car was putting too much of a drain on the system and preventing the car from starting. I don't know why these would come on at all since the switch was in the off position.


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## The HACK (Dec 19, 2001)

NickD said:


> My parking definitely weren't on. As I remember walking around the front of the car.
> 
> I was thinking perhaps that the xenon lights powering up when I was trying to start the car was putting too much of a drain on the system and preventing the car from starting. I don't know why these would come on at all since the switch was in the off position.


Once your batteries are drained the lights won't stay on. What is WEIRD is it requires a lot more VOLTAGE to crank the Xenons than the regular lightbulbs. Eitherway, it still sounds like you're about due for a new battery anyway. I believe Interstate is the only aftermarket battery maker that makes one compatible with BMWs.


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## Kaz (Dec 21, 2001)

The HACK said:


> Once your batteries are drained the lights won't stay on. What is WEIRD is it requires a lot more VOLTAGE to crank the Xenons than the regular lightbulbs. Eitherway, it still sounds like you're about due for a new battery anyway. I believe Interstate is the only aftermarket battery maker that makes one compatible with BMWs.


This is incorrect. I believe the Philips LVQ212 ballast will start on as little as 9VDC. It's the ballast/igniter's job to step that up to create the brief ~20,000v ignition voltage and the 85v running voltage.

Also, I believe US OE BMW batteries are from Douglas, not Interstate.


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## NickD (Jul 16, 2003)

Ok, I just spent the past 3 hours locating a interstate battery, the model is MPT-91 for an E46. Got a ride there from a co-worker, came back, installed the new battery, ($3.50 for a vent kit) and it started right up, no problems. I guess the car does wierd thing when the battery gets weak (like turning on my headlights).

Thanks for all your help guys!


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