Charging voltage too high?

e90yyc · 02-22-2018, 04:04 PM

Hello from Canada!

First post here, but have been lurking for a while…

I’ve got a meticulously maintained 2007 328xi with about 170,000 miles on it. Bought it as an inexpensive vehicle to drive while I’m in school (ha...). I love the brand, and I love working on cars, so I figured this should give me ample opportunity to do so

. Previously had a 2017 340i xDrive w/ M Performance II, but that had to go when I surrendered my income and returned to school

. Despite the chasmic difference in performance, I honestly think the E90 is nicer to drive. It has an organic quality to it that is largely absent in the F30. Anyway...

Sorry in advance if I’ve missed something, but I have UTFSE and have also consulted the Bentley manual… nada. My question is a bit more specific than what I have been able to find answers to so far.

The question:

Considering the facts outlined below, is 15 volts too high for charging/alternator output?

The facts:

Battery replaced <2000 miles ago (OEM)
New battery was registered upon replacement
Confirmed the presence of IBS module when replacing battery
No material difference in charging voltage was noted pre or post replacement
BC/Cluster hidden menu value 09.00 shows charging voltage of approximately 14.5-15.0 (seems to bounce around a bit; I believe this is normal)
My Fluke meter indicates charging voltage of approximately 15 volts at B+ / ground terminals in engine bay
Outside temperatures are consistently between 30 and 0 degrees fahrenheit

Obviously the BC menu values are within spec. My concern is the reading I’m getting from my multimeter, whose value I would feel inclined to give preference to.

My hypothesis:

Due to cold weather, the IBS sensor temperature value is prompting the DME to request additional charging voltage.

-------------------------------------------

I recall having read somewhere that the charging voltage may be increased in cold temperatures (presumably based on battery temp per IBS and not ambient temp). I'm assuming this is the case here, but I’d like to get some of you folks’ expert opinions on the matter before I fry my brand new battery.

Any/all info is appreciated.

Thanks in advance for your help!!!

floydarogers · 02-22-2018, 04:36 PM

14.7 is nominal, so I wouldn't think that 15 is too high...

mecheng77 · 02-22-2018, 04:37 PM

You sure battery was registered? INPA shows
When it was done

e90yyc · 02-22-2018, 04:42 PM

Quote:

Originally Posted by floydarogers

14.7 is nominal, so I wouldn't think that 15 is too high...

Thanks! This definitely helps.

Quote:

Originally Posted by mecheng77

You sure battery was registered? INPA shows
When it was done

Yup. Did it myself and then went back in and confirmed the date and mileage stamp at replacement. Oddly enough there was no previous record of the battery having been replaced... Seems strange given the mileage, but maybe it isn't??

TheeGovernor · 02-22-2018, 04:58 PM

What type of battery? Flooded batteries cans see up too 15.5 volts, but an agm should see more then 14.9.

e90yyc · 02-22-2018, 05:09 PM

Quote:

Originally Posted by TheeGovernor

What type of battery? Flooded batteries cans see up too 15.5 volts, but an agm should see more then 14.9.

Flooded

mecheng77 · 02-22-2018, 05:11 PM

Quote:

Originally Posted by e90yyc

Thanks! This definitely helps.

Yup. Did it myself and then went back in and confirmed the date and mileage stamp at replacement. Oddly enough there was no previous record of the battery having been replaced... Seems strange given the mileage, but maybe it isn't??

I noticed same, 2007 and no battery charge registered
And it was an OEM bmw battery

Makeuwunder · 02-22-2018, 05:23 PM

I had this issue with my car also. It was charging at 15.6 volts which the car started shutting down modules and I started getting error messages as the modules shut down. I ended up changing my alternator out and it fixed the problem.

9krpmrx8 · 02-22-2018, 05:28 PM

Be very careful, I had an alternator fail in this way, it was over charging (16V) on another car I own and it did a few thousand dollars worth of damage when it overcharged and exploded the battery and ruined the ABS modulator.

e90yyc · 02-22-2018, 06:01 PM

Hmm. Definitely don’t want my battery to explode, haha!

Really appreciate the input, but I’m still wondering whether the DME varies charging voltage based on IBS temperature input. What little info I’ve found so far seems to indicate this to be the case, but I’m hoping for confirmation. The battery is new, but if DME bumps voltage based on temp and not age/health, then this would make sense.

I should also reiterate that my BC voltage reading is around 14.5, and my multimeter is around 15. Mayyybe 15.1 for a brief moment. So still a ways off from the voltages some of you have seen leading up to major issues, IMO.

Would changing the voltage regulator be a good starting point if I was concerned about this?

I suppose in summary what I was asking in my original post is:

If my charging voltage is 15 volts when ambient temp is <30 Fahrenheit, would I reasonably expect it to be 14.5 once the temp is >60 Fahrenheit? Or is this total BS?

Not to push my luck, but if there’s anyone out there in a cold climate who feels like doing a little experiment, I would be curious what your multimeter reading is at idle...

Thanks for all the input!!!

mxchris727 · 02-22-2018, 06:02 PM

You can replace the voltage regulator on the alternator: https://www.ecstuning.com/b-bosch-pa...317561939~bos/

e90yyc · 02-22-2018, 06:05 PM

Quote:

Originally Posted by mxchris727

You can replace the voltage regulator on the alternator: https://www.ecstuning.com/b-bosch-pa...317561939~bos/

Thanks. Sounds like that might be my next step.

Do you know if OEM alternator is Bosch? I tried to get a visual on mine but no dice...

e90yyc · 02-22-2018, 06:42 PM

Looks like I may have answered my own question...

I'll definitely keep an eye on it, but it seems like this is normal. If it's still reading 15V @ 77 degrees Fahrenheit then I'll certainly be digging deeper.

http://batteryuniversity.com/learn/a...w_temperatures

From above site:

Quote:

Voltage compensation prolongs battery life when operating at temperature extremes.

tlow98 · 02-22-2018, 06:48 PM

Early 2009 build, OE battery here, too.

They last a while!

e90yyc · 02-22-2018, 07:03 PM

Quote:

Originally Posted by tlow98

Early 2009 build, OE battery here, too.

They last a while!

Nice!

Glad to know they’re so long-lasting.

I thought for sure this would have been on its second battery already, but it looked original and there was no previous record of replacement.

In fact, if it weren’t for the Arctic temperatures where I live, I’m sure I could have gotten by even longer with the original battery...

Vatrica · 05-19-2018, 03:31 PM

Hello guys, this is my first post on the forum, I hope I'm doing everything right.

My 330xd is randomly going crazy with voltage and its driving me crazy.

I drive with no issues for a couple of months sometimes and boom voltage starts jumping from 9V to 20V. I stop the engine, lock the door for a couple of seconds and everything is fine again(13.8-14.1V)
Up to this point, I changed JBE junction box in glovebox, alternator and voltage regulator, disconnected IBS.
Today I also checked all the connectors in DME under the hood,all looking good.
Any advice is highly appreciated.

ivibmw · 01-19-2020, 04:32 AM

Quote:

Originally Posted by Vatrica

Hello guys, this is my first post on the forum, I hope I'm doing everything right.

My 330xd is randomly going crazy with voltage and its driving me crazy.

I drive with no issues for a couple of months sometimes and boom voltage starts jumping from 9V to 20V. I stop the engine, lock the door for a couple of seconds and everything is fine again(13.8-14.1V)
Up to this point, I changed JBE junction box in glovebox, alternator and voltage regulator, disconnected IBS.
Today I also checked all the connectors in DME under the hood,all looking good.
Any advice is highly appreciated.

Did you get this figured out?

02-22-2018, 04:04 PM	#1
e90yyc Art Collector 2425 Rep 3,448 Posts Drives: 2007 328xi (GM-delete 6MT) Join Date: Feb 2018 Location: Canada iTrader: (0)	Charging voltage too high? Hello from Canada! First post here, but have been lurking for a while… I’ve got a meticulously maintained 2007 328xi with about 170,000 miles on it. Bought it as an inexpensive vehicle to drive while I’m in school (ha...). I love the brand, and I love working on cars, so I figured this should give me ample opportunity to do so . Previously had a 2017 340i xDrive w/ M Performance II, but that had to go when I surrendered my income and returned to school . Despite the chasmic difference in performance, I honestly think the E90 is nicer to drive. It has an organic quality to it that is largely absent in the F30. Anyway... Sorry in advance if I’ve missed something, but I have UTFSE and have also consulted the Bentley manual… nada. My question is a bit more specific than what I have been able to find answers to so far. The question: Considering the facts outlined below, is 15 volts too high for charging/alternator output? The facts: Battery replaced <2000 miles ago (OEM) New battery was registered upon replacement Confirmed the presence of IBS module when replacing battery No material difference in charging voltage was noted pre or post replacement BC/Cluster hidden menu value 09.00 shows charging voltage of approximately 14.5-15.0 (seems to bounce around a bit; I believe this is normal) My Fluke meter indicates charging voltage of approximately 15 volts at B+ / ground terminals in engine bay Outside temperatures are consistently between 30 and 0 degrees fahrenheit Obviously the BC menu values are within spec. My concern is the reading I’m getting from my multimeter, whose value I would feel inclined to give preference to. My hypothesis: Due to cold weather, the IBS sensor temperature value is prompting the DME to request additional charging voltage. ------------------------------------------- I recall having read somewhere that the charging voltage may be increased in cold temperatures (presumably based on battery temp per IBS and not ambient temp). I'm assuming this is the case here, but I’d like to get some of you folks’ expert opinions on the matter before I fry my brand new battery. Any/all info is appreciated. Thanks in advance for your help!!! Last edited by e90yyc; 02-22-2018 at 04:48 PM.. Reason: clarity
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02-22-2018, 04:36 PM	#2
floydarogers Curmudgeon and Pedant 690 Rep 3,489 Posts Drives: 2010 335d, 2014 328d Join Date: Nov 2012 Location: Bellevue, WA iTrader: (0)	14.7 is nominal, so I wouldn't think that 15 is too high...
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02-22-2018, 04:37 PM	#3
mecheng77 Colonel 1006 Rep 2,243 Posts Drives: 2007 328i / 2014 M235i Join Date: Nov 2017 Location: Ontario Canada iTrader: (0) Garage List [0.00] [0.00]	You sure battery was registered? INPA shows When it was done
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02-22-2018, 04:58 PM	#5
TheeGovernor Life is better with burnouts 97 Rep 611 Posts Drives: BMW Join Date: Dec 2011 Location: Mile High iTrader: (4) Garage List 1996 Toyota Forklift [0.00] 2007 BMW 335i [0.00]	What type of battery? Flooded batteries cans see up too 15.5 volts, but an agm should see more then 14.9.
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02-22-2018, 05:23 PM	#8
Makeuwunder First Lieutenant 62 Rep 307 Posts Drives: 07 335i Join Date: Jul 2013 Location: Savannah, Ga iTrader: (1)	I had this issue with my car also. It was charging at 15.6 volts which the car started shutting down modules and I started getting error messages as the modules shut down. I ended up changing my alternator out and it fixed the problem.
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02-22-2018, 05:28 PM	#9
9krpmrx8 Clean is the new cool, keep it that way. 808 Rep 1,685 Posts Drives: 11' Alpine White 335i Sedan Join Date: Jan 2016 Location: San Antonio, Texas iTrader: (0)	Be very careful, I had an alternator fail in this way, it was over charging (16V) on another car I own and it did a few thousand dollars worth of damage when it overcharged and exploded the battery and ruined the ABS modulator.
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02-22-2018, 06:01 PM	#10
e90yyc Art Collector 2425 Rep 3,448 Posts Drives: 2007 328xi (GM-delete 6MT) Join Date: Feb 2018 Location: Canada iTrader: (0)	Hmm. Definitely don’t want my battery to explode, haha! Really appreciate the input, but I’m still wondering whether the DME varies charging voltage based on IBS temperature input. What little info I’ve found so far seems to indicate this to be the case, but I’m hoping for confirmation. The battery is new, but if DME bumps voltage based on temp and not age/health, then this would make sense. I should also reiterate that my BC voltage reading is around 14.5, and my multimeter is around 15. Mayyybe 15.1 for a brief moment. So still a ways off from the voltages some of you have seen leading up to major issues, IMO. Would changing the voltage regulator be a good starting point if I was concerned about this? I suppose in summary what I was asking in my original post is: If my charging voltage is 15 volts when ambient temp is <30 Fahrenheit, would I reasonably expect it to be 14.5 once the temp is >60 Fahrenheit? Or is this total BS? Not to push my luck, but if there’s anyone out there in a cold climate who feels like doing a little experiment, I would be curious what your multimeter reading is at idle... Thanks for all the input!!!
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02-22-2018, 06:02 PM	#11
mxchris727 Captain 193 Rep 666 Posts Drives: '03 M5, '06 325i, '12 M3 Join Date: Aug 2012 Location: Westport, CT iTrader: (0)	You can replace the voltage regulator on the alternator: https://www.ecstuning.com/b-bosch-pa...317561939~bos/ __________________ BMW GT1 (INPA, DIS, WinKFP, ect..), ISTA/P & /D is up and running! PM me if you want to stop by and code your car.
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02-22-2018, 06:48 PM	#14
tlow98 Major General 2188 Rep 5,001 Posts Drives: 2009 E91, 2014 F15 x35i Join Date: Aug 2011 Location: Bay Area iTrader: (2)	Early 2009 build, OE battery here, too. They last a while!
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05-19-2018, 03:31 PM	#16
Vatrica Registered 0 Rep 2 Posts Drives: 330xd e90 Join Date: May 2018 Location: Split, Croatia iTrader: (0)	Hello guys, this is my first post on the forum, I hope I'm doing everything right. My 330xd is randomly going crazy with voltage and its driving me crazy. I drive with no issues for a couple of months sometimes and boom voltage starts jumping from 9V to 20V. I stop the engine, lock the door for a couple of seconds and everything is fine again(13.8-14.1V) Up to this point, I changed JBE junction box in glovebox, alternator and voltage regulator, disconnected IBS. Today I also checked all the connectors in DME under the hood,all looking good. Any advice is highly appreciated.
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