Battery light flickering on startup
 

Hi guys,

I noticed Saturday that my battery light has been flickering on startup. It continues to do this now. Is this a sign for me to get a new battery, or is the alternator slowly on its way out?

I use a Bluetooth transmitter that plugs into the cigarette lighter up front that gives me my battery levels. Prior to starting the car, it's 12.5V and while the car is running it's 13.8V. This seems within range. I have a small road trip coming up this Thursday so just trying to get an idea of what may be going on.

Thanks in advance.

in my experience, battery light has always been an alternator issue.

alernator. better safe than be stranded....especially in this heat !

Test DO NOT GUESS.

Tools Volt meter (digital) after confirming all the posts are clean and tightened including all the grounds in the trunk area. This will confirm no water in the well, positive cable has NOT been compromised by the explosive connector.
Read/Test at battery post in the trunk first. Reading engine off over 12.5 V?
Start engine, Read at battery posts. Over 13.5V?
Do a Voltage drop test on the cables. See image below. and video
https://www.youtube.com/watch?v=3-9oZuX6-Pg

Move to under hood jump post +, tight? Read Voltage engine running...over 12.5V and steady? Bring RPMs to 2500, reading?
Turn on all the accessories while reading voltage. Still above 13.5V? Steady? bring RPMs up to 2500. Steady or moving all over?

The RPM tests show regulator function with speed and load. Most of these alts die due to the regulator loosing connection at the slip ring or the reg going dumb. The voltage will bounce all over the place.

Options: If everything points to the alternator then look at the back of your alt and buy a NEW not rebuilt unit (Bosch or Valeo) unless you are willing to install and reinstall until you get a functional one. See all the other postings on charging issues and rebuilt alternators for examples of those who have tried the price path before you. Cheap is not the way to go. But as they say, it is your car, time, wallet, etc.....

Every time my alternator has gone, it started with an intermittent battery light.

Thanks, guys. I'm going to drop it off at the Indy tomorrow.

How much should I expect to pay for an alternator job?

Depends on whether you go with a reman. or new alternator. Job shouldn't take more than a couple hours.

Why would you pay a shop to do a quick test and replacement of an alternator? Lack of skills/time? The tools required will pay for themselves in one effort. Time required on you 3.0 application 2 hrs including replacing the drive belts as they are more than likely toast as well.

DIY costs: Alt $200, belts $40

Shop: $300/400 parts, Labor 2.5 hrs @ $125 per hr = $325 Totals $625 min.

Note: Pricing is based on real life not corner gas station skill sets

depends if the OP has the water cooled alt or not . That's still like $4 for Bosch and $5 for Roundel brand, both reman though...

Unfortunately, lack of skills:(

Thanks for the feedback.

The OP has a 3.0 engine, never seen one with a water cooled version Alternator. We need to find you a few friends in the NYC area where you could learn a few things.., Anyone out there interested?

Battery light flickering on startup
 

Alternator on E53 not very difficult of a job. I rebuilt mine for $20 vs replace. I have no problem with remanufactured motors (generators) are very robust simple machines. I would use branded reman over knock off new


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I agree, in this case especially a good rebuilt is better than a new knock-off. The reman Bosch unit is actually more money than the made in China New Bosch. Flickering light is very likely brushes failing in alternator.

I just replaced my battery 1 month ago. Red batt light on dash showed up Saturday. Had to get alternator replaced yesterday. $750 for part, 2 hours of labor.


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I took it to my indy shop and he confirmed it was the alternator. He said he will order the part and to bring it in on Friday.

Keep the old one. Especially if valeo; they can be refurbished for add little as $20. I would be interested in paying for you to ship it to me. I have two E53! It would be great to have one on hand for the inevitable.


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Update:

Dropped the car off Friday morning to have the alternator changed. The mechanic calls me at 1 pm and tells me the alternator pulley is making noise and probably worn out, and he suggests that I change it in addition to another belt, I forgot the name of the other. Annoyed at the additional cost, but I ok it nonetheless. Mechanic calls again at 3:45 pm and says after changing the alternator and the aforementioned belts, the vehicle is still having issues with the battery light flashing and now having starting issues, which I did not bring it in with starting issues. He states the bad alternator drained my battery which may be the original battery and he suggests that I change the battery to ensure all problems are resolved. He said the new battery would be $245. Now I'm more annoyed. I go ahead and ok the new battery.

I pick up the vehicle at 5:30 and all is well. No flickering battery light upon starting. Drove home and parked it. Stepped back out at 9 pm to head to the grocery store and upon starting I noticed the battery light is flickering once again. Pissed at this point, I checked my battery level and it's reading 13.5 and 13.8 with the ignition running.

Called my indy the next morning, he told me due to the holiday I would need to bring the vehicle in on Tuesday. I really did not drive much on Saturday but the flickering on startup still persists. Around 8 pm tonight on the way back home with my wife I noticed the battery light is now flashing while driving, which it was not doing prior to bringing it into the shop. By the time I got home the battery light was no longer flashing it was completed illuminated and staying on.

What's really going on here? Could it be a defective alternator or bad battery installed or bad workmanship? I know these question will be answered on Tuesday, but the X is really letting me down at this point. I'm at the point where I can't stomach the mechanic telling me something else is wrong after spending $800 dollars. Now with one more day to wait, I'm not even sure if it's safe to drive the X.

The wife suggests getting rid of the X. At only 72K, I have dumped a considerably amount cash into repairs over the past year. I just did right front bearing and CV three weeks ago.

Just saw this. The mechanic might still have the old alternator in his possession.

When it's on steady it's usually the alternator. Did you check running voltage after it came on steady? Could be a defective alternator.

'

Wow, another Cliff Clavin. Like someone mentions before 3.0 did not come with a water cooled alternator. If I was a Trump supporter I would tweet "Fake Advice".

No, it is not safe to drive the X at this point. Either use your other car or go and rent a car for the day. The battery is not charging and driving on the battery will eventually drain the battery to the point that it can no longer provide electricity to operate the car. The car will stop running and it could be at the most inopportune time like on the highway.

Remember a Happy wife mean a Happy life.

Indications are defective replacement alternator (or not tightened nut; I did that myself). Save that it could be a bad ground strap. The battery was likely bad as happens often when the alternator is bad


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I wish I had seen this earlier. Took the X out this morning to go to Autozone to get a brake light bulb since that came on my dash. When I got back to try and start her up the X was completely dead. Nothing at all when trying to start, just dead. Tried to get a jump start but to no avail. I called road service and had the X towed and left in front of the shop that did the work.

Hope you guys are enjoying your labor day holiday and are barbequing.

I would never try to jump-start an X with a dead battery. The power surge from the other car alternator along with your dead battery is sometimes a perfect storm to fry some electronic components. Better to take the battery out or hookup a charger at the jump points to slowly recharge the battery.