Possible Alternator Issue

jdoublehcubed · 02-04-2016, 01:40 AM

I recently started seeing a strange electrical issue, that I suspect is a failing voltage regulator in my alternator. I read this thread
http://www.zpost.com/forums/showthre...=669131&page=2

I have the occasional flashing of warning lights, as well as the stereo/nav restarting. I've been logging the voltage through torque/obdii reader, and here is my question. The voltage I see from the alternator seems to fluctuate a lot, but never shows the extreme spikes that others have reported. The dips down to around 12V happen just after the RPMs drop when I take my foot of the accelerator. Here are a couple screen shots of the voltage log.

What do you guys think? Alternator or battery?

Westersund · 02-04-2016, 03:06 AM

Worn coals on the regulator would be my bet. Cheap and easy fix.

elerner61 · 02-04-2016, 08:25 AM

Never heard of a Voltage Regulator Coal (and couldn't find a good explanation on the web).

Education please

chickdr · 02-04-2016, 08:36 AM

How old is your battery? It could be a combination of the two. If more than 5yrs old I would swap it, or at least have it checked.

longress · 02-04-2016, 08:43 AM

Alternator is suspect assuming all your connections are clean and tight and your belt isn't slipping. Voltage shouldn't dip below 13v with the engine running.

jdoublehcubed · 02-04-2016, 11:39 AM

Quote:

Originally Posted by chickdr

How old is your battery? It could be a combination of the two. If more than 5yrs old I would swap it, or at least have it checked.

Battery is around 2.5 years old, but its the really small Deka one. I figure the battery is probably on its last legs also, but I've had a dead battery before and never seen it do this. Also, if there is a problem with the alternator, I want to make sure its fixed before I install another battery.

jdoublehcubed · 02-04-2016, 03:58 PM

Quote:

Originally Posted by elerner61

Never heard of a Voltage Regulator Coal (and couldn't find a good explanation on the web).

Education please

Same question please.

StickMon · 02-04-2016, 04:37 PM

That's about what my voltage looked like before I got a limp mode, TPS, and Throttle Actuator codes.
Was my battery.
When my alternator went it failed hard with no warning.
Voltage was a 45° downward slope.

jdoublehcubed · 02-04-2016, 05:10 PM

Quote:

Originally Posted by StickMon

That's about what my voltage looked like before I got a limp mode, TPS, and Throttle Actuator codes.
Was my battery.
When my alternator went it failed hard with no warning.
Voltage was a 45° downward slope.

When your alternator failed, did it go quick enough to avoid killing the battery as well? My primary concern at the moment with replacing the battery is that I'm overlooking an alternator problem and it will end up trashing the new battery.

StickMon · 02-04-2016, 06:56 PM

I noticed the car was idling kind of funny on my way to work.
About 10 miles into the trip, while at a stop light, I punched up Volts on DashCommand and I was at 11.7 V.
I revved the engine to see if it would go up, because sometimes when the regulator goes you can still get charging at higher RPMs, but it went down, so regulator was completely dead.
Then and only just then did the yellow batt indicator come on on the dash.
I cut all unnecessary loads and high tailed back home.
Was at about 10.7 V when I got home.
Battery was about 2 year old H6 AGM, and seemed to survive.

jdoublehcubed · 02-04-2016, 07:57 PM

Quote:

Originally Posted by StickMon

I noticed the car was idling kind of funny on my way to work.
About 10 miles into the trip, while at a stop light, I punched up Volts on DashCommand and I was at 11.7 V.
I revved the engine to see if it would go up, because sometimes when the regulator goes you can still get charging at higher RPMs, but it went down, so regulator was completely dead.
Then and only just then did the yellow batt indicator come on on the dash.
I cut all unnecessary loads and high tailed back home.
Was at about 10.7 V when I got home.
Battery was about 2 year old H6 AGM, and seemed to survive.

Thanks, that's good to know. Sounds like my problems aren't severe enough to be an alternator, I guess I'll pick up a replacement battery.

longress · 02-04-2016, 09:23 PM

Your alternator can provide the car with all the current needed to run the car. The battery's job is to operate the starter and to stabilize voltage not supplement the alternator or do its job. I can't imagine that this is not a bad alternator. Not saying your battery might not be damaged now as well as the car may be trying unsuccessfully to run off the battery.

Westersund · 02-05-2016, 04:14 AM

Quote:

Originally Posted by elerner61

Never heard of a Voltage Regulator Coal (and couldn't find a good explanation on the web).

Education please

The 2 "pins" sticking out on the top of this regulator are coals/carbon and they get worn thus the generator/alternator can't produce enough current. Maybe it's a bad translation on my part, English is not my native language after all. The coals/carbon are replacable, though I usually change the entire regulator since it's so cheap anyway.

StickMon · 02-05-2016, 03:35 PM

^ Brushes!

Do alternators have brushes?
I thought that was just generators.
I don't think I've ever taken an alternator apart, so I may be wrong.

Westersund · 02-05-2016, 05:28 PM

Quote:

Originally Posted by StickMon

^ Brushes!

Do alternators have brushes?
I thought that was just generators.
I don't think I've ever taken an alternator apart, so I may be wrong.

I have no idea what the difference is between an alternator and a generator, they do the same thing no? In Sweden both alternator and generator translates to "generator". As with coal and carbon both are "kol", hence the occational brain farts from me. English have so many different words meaning the same thing compared to Swedish.

Edit: After some Googling it seems like the part used in a car is called alternator in English. It converts mechanical movement into AC and it is converted in the diode bridge to DC. A generator converts mechanical movement into DC straight away. Seems like it's only the Alternator that have "brushes".

StickMon · 02-05-2016, 11:59 PM

Exactly.
The brushes are part of the "commutator" which does the same job as the diode bridge, but mechanically with parts that wear out.
Low loss, high current silicon diodes became plentiful in the late 60s.
Prior to that, the generator was the only good option.

dreamingat30fps · 02-06-2016, 01:05 AM

Mine went recently. The day before I got a couple of flashing lights like ABS, traction etc. Next day they had gone away so I kinda shrugged it off. Then on the way home from work it died in the middle of the highway.

jdoublehcubed · 02-08-2016, 01:57 AM

Quote:

Originally Posted by dreamingat30fps

Mine went recently. The day before I got a couple of flashing lights like ABS, traction etc. Next day they had gone away so I kinda shrugged it off. Then on the way home from work it died in the middle of the highway.

where did you get a replacement voltage regulator, the link in the thread above shows them as unavailable.

StickMon · 02-08-2016, 02:55 PM

American Engines Co.?
That's where I got mine. Looks like they ran out.

dreamingat30fps · 02-09-2016, 02:30 PM

Quote:

Originally Posted by jdoublehcubed

where did you get a replacement voltage regulator, the link in the thread above shows them as unavailable.

I just replaced the whole thing with a rebuilt.

jdoublehcubed · 02-10-2016, 11:25 AM

just replaced the battery and had the same problem, so i guess its the alternator. now i just need to find that voltage regulator.

SaltyNC · 02-10-2016, 11:34 AM

Quote:

Originally Posted by jdoublehcubed

just replaced the battery and had the same problem, so i guess its the alternator. now i just need to find that voltage regulator.

http://www.ebay.com/itm/172003595546

Will that work?

Salty

02-04-2016, 01:40 AM	#1
jdoublehcubed Mechanical Engineer 96 Rep 1,025 Posts Drives: 2006 Z4MR, Imola Red Join Date: Jul 2012 Location: Anaheim, CA iTrader: (1)	Possible Alternator Issue I recently started seeing a strange electrical issue, that I suspect is a failing voltage regulator in my alternator. I read this thread http://www.zpost.com/forums/showthre...=669131&page=2 I have the occasional flashing of warning lights, as well as the stereo/nav restarting. I've been logging the voltage through torque/obdii reader, and here is my question. The voltage I see from the alternator seems to fluctuate a lot, but never shows the extreme spikes that others have reported. The dips down to around 12V happen just after the RPMs drop when I take my foot of the accelerator. Here are a couple screen shots of the voltage log. What do you guys think? Alternator or battery? Attached Images
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02-04-2016, 03:06 AM	#2
Westersund Captain 496 Rep 874 Posts Drives: BMW Join Date: Nov 2011 Location: Hallstahammar iTrader: (1)	Worn coals on the regulator would be my bet. Cheap and easy fix.
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02-04-2016, 08:25 AM	#3
elerner61 Major 157 Rep 1,107 Posts Drives: '07 Z4M Roadster Join Date: May 2011 Location: Mount Kisco, NY iTrader: (0)	Never heard of a Voltage Regulator Coal (and couldn't find a good explanation on the web). Education please
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02-04-2016, 08:36 AM	#4
chickdr Lieutenant Colonel 140 Rep 1,990 Posts Drives: 2006 M Roadster Join Date: May 2009 Location: Buford, GA iTrader: (0)	How old is your battery? It could be a combination of the two. If more than 5yrs old I would swap it, or at least have it checked.
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02-04-2016, 08:43 AM	#5
longress Second Lieutenant 105 Rep 233 Posts Drives: 2007 Z4M Coupe Join Date: Oct 2015 Location: Wyoming iTrader: (2)	Alternator is suspect assuming all your connections are clean and tight and your belt isn't slipping. Voltage shouldn't dip below 13v with the engine running.
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02-04-2016, 04:37 PM	#8
StickMon My other car is on Mars 636 Rep 3,124 Posts Drives: 2006 MR Join Date: Feb 2011 Location: Lo-Cal iTrader: (1)	That's about what my voltage looked like before I got a limp mode, TPS, and Throttle Actuator codes. Was my battery. When my alternator went it failed hard with no warning. Voltage was a 45° downward slope. __________________ Warning: May contain traces of nuts.
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02-04-2016, 06:56 PM	#10
StickMon My other car is on Mars 636 Rep 3,124 Posts Drives: 2006 MR Join Date: Feb 2011 Location: Lo-Cal iTrader: (1)	I noticed the car was idling kind of funny on my way to work. About 10 miles into the trip, while at a stop light, I punched up Volts on DashCommand and I was at 11.7 V. I revved the engine to see if it would go up, because sometimes when the regulator goes you can still get charging at higher RPMs, but it went down, so regulator was completely dead. Then and only just then did the yellow batt indicator come on on the dash. I cut all unnecessary loads and high tailed back home. Was at about 10.7 V when I got home. Battery was about 2 year old H6 AGM, and seemed to survive. __________________ Warning: May contain traces of nuts.
	Appreciate 0 Quote

02-04-2016, 09:23 PM	#12
longress Second Lieutenant 105 Rep 233 Posts Drives: 2007 Z4M Coupe Join Date: Oct 2015 Location: Wyoming iTrader: (2)	Your alternator can provide the car with all the current needed to run the car. The battery's job is to operate the starter and to stabilize voltage not supplement the alternator or do its job. I can't imagine that this is not a bad alternator. Not saying your battery might not be damaged now as well as the car may be trying unsuccessfully to run off the battery.
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02-05-2016, 03:35 PM	#14
StickMon My other car is on Mars 636 Rep 3,124 Posts Drives: 2006 MR Join Date: Feb 2011 Location: Lo-Cal iTrader: (1)	^ Brushes! Do alternators have brushes? I thought that was just generators. I don't think I've ever taken an alternator apart, so I may be wrong. __________________ Warning: May contain traces of nuts.
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02-05-2016, 11:59 PM	#16
StickMon My other car is on Mars 636 Rep 3,124 Posts Drives: 2006 MR Join Date: Feb 2011 Location: Lo-Cal iTrader: (1)	Exactly. The brushes are part of the "commutator" which does the same job as the diode bridge, but mechanically with parts that wear out. Low loss, high current silicon diodes became plentiful in the late 60s. Prior to that, the generator was the only good option. __________________ Warning: May contain traces of nuts.
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02-06-2016, 01:05 AM	#17
dreamingat30fps Lieutenant Colonel 5322 Rep 1,907 Posts Drives: Miata, Cayenne, Model 3, F350 Join Date: Jan 2010 Location: South Florida & NC iTrader: (1)	Mine went recently. The day before I got a couple of flashing lights like ABS, traction etc. Next day they had gone away so I kinda shrugged it off. Then on the way home from work it died in the middle of the highway.
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02-08-2016, 02:55 PM	#19
StickMon My other car is on Mars 636 Rep 3,124 Posts Drives: 2006 MR Join Date: Feb 2011 Location: Lo-Cal iTrader: (1)	American Engines Co.? That's where I got mine. Looks like they ran out. __________________ Warning: May contain traces of nuts.
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02-10-2016, 11:25 AM	#21
jdoublehcubed Mechanical Engineer 96 Rep 1,025 Posts Drives: 2006 Z4MR, Imola Red Join Date: Jul 2012 Location: Anaheim, CA iTrader: (1)	just replaced the battery and had the same problem, so i guess its the alternator. now i just need to find that voltage regulator.
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