dead battery and then....

racerbruce · 10-07-2012, 08:47 AM

Dead battery when leaving for work; jumpered using my bride's 3 series; bmw dealer checked charging system - fine; battery was replaced 1.25 yrs ago and was checked - fine; car has been fine since this one instance.

i suspect that opening the top before starting the car, driving only 5 miles to the park n ride to take the bus, and then opening the top before starting the car upon returning to the park n ride in the eve and driving only 5 miles home did not allow enough time to charge the system.

it's been nearly a month since this one-time instance and all is well.

XMetal · 10-07-2012, 11:07 AM

Get a battery tender and use it once per week. Sounds like you ultra short commute isn't enough to recharge the battery.

Why not just start the car and then open the top? You would want to idle the car for ~15 seconds or so anyway for all the fluids to cycle through before driving off. Mind as well spent that time wisely

G80indy · 10-07-2012, 06:09 PM

get an AGM battery

RobMCoupe · 10-07-2012, 06:30 PM

I don't think open/close top drain too much battery. It takes lots of amp to crank the car over. 5 miles won't recharge your battery after starting the car. Your oil probably not up to temp with such a short trip. I always let my oil come to normal temp before turning engine off even if I have to drive around for awhile.

Caddyshk · 10-07-2012, 07:13 PM

Quote:

Originally Posted by 330indy

get an AGM battery

It is AGM

realast8 · 10-07-2012, 09:05 PM

Perhaps that one time you left the door ajar / left the radio on / left a charger in the cig lighter / left an interior light on, etc.

chickdr · 10-07-2012, 09:46 PM

Quote:

Originally Posted by Caddyshk

It is AGM

It MAY be AGM, but he said he had replaced it 1.25 yrs ago. Not stated if he went AGM, or not. I replaced my AGM with a standard battery due to cost savings. I don't think AGM vs LA will make any difference in the OP's case as they both have the similar specs and will discharge if not run enough.

G80indy · 10-08-2012, 01:34 AM

Quote:

Originally Posted by chickdr

It MAY be AGM, but he said he had replaced it 1.25 yrs ago. Not stated if he went AGM, or not. I replaced my AGM with a standard battery due to cost savings. I don't think AGM vs LA will make any difference in the OP's case as they both have the similar specs and will discharge if not run enough.

AGMs have less static discharge than FLAs.
I agree that driving around more than 5 miles is needed, but to also circulate and heat up those fluids. A battery tender is always a good idea for max life to any battery that doesn't see highway driving.

10-07-2012, 08:47 AM	#1
racerbruce Brigadier General 3854 Rep 3,004 Posts Drives: 21 X3 & 13 335is E93 Join Date: Dec 2009 Location: Seattle iTrader: (1)	dead battery and then.... Dead battery when leaving for work; jumpered using my bride's 3 series; bmw dealer checked charging system - fine; battery was replaced 1.25 yrs ago and was checked - fine; car has been fine since this one instance. i suspect that opening the top before starting the car, driving only 5 miles to the park n ride to take the bus, and then opening the top before starting the car upon returning to the park n ride in the eve and driving only 5 miles home did not allow enough time to charge the system. it's been nearly a month since this one-time instance and all is well. __________________ Racerbruce
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10-07-2012, 11:07 AM	#2
XMetal Colonel 1136 Rep 2,867 Posts Drives: Anything Join Date: Apr 2010 Location: SoCal iTrader: (0) Garage List 2008 Z4M Coupe [10.00] 2018 Audi S3 [0.00] 2004 X5 [8.50]	Get a battery tender and use it once per week. Sounds like you ultra short commute isn't enough to recharge the battery. Why not just start the car and then open the top? You would want to idle the car for ~15 seconds or so anyway for all the fluids to cycle through before driving off. Mind as well spent that time wisely
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10-07-2012, 06:09 PM	#3
G80indy Save the Manuals 1714 Rep 2,937 Posts Drives: Z3, E46, G80 Join Date: May 2005 Location: Indy iTrader: (0)	get an AGM battery __________________ 2023 G80 6MT, CCBs 2002 330i Dinan, 5MT 2000 Z3 Conforti, 5MT
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10-07-2012, 06:30 PM	#4
RobMCoupe Captain 60 Rep 932 Posts Drives: 2007 Z4 M Coupe Join Date: Feb 2010 Location: Bay Area iTrader: (6)	I don't think open/close top drain too much battery. It takes lots of amp to crank the car over. 5 miles won't recharge your battery after starting the car. Your oil probably not up to temp with such a short trip. I always let my oil come to normal temp before turning engine off even if I have to drive around for awhile.
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10-07-2012, 09:05 PM	#6
realast8 New Member 3 Rep 22 Posts Drives: 2006 M Roadster and 2012 750i Join Date: May 2011 Location: Oakville, Canada iTrader: (0)	Perhaps that one time you left the door ajar / left the radio on / left a charger in the cig lighter / left an interior light on, etc.
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