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Old 09-24-2016, 11:22 AM   #26
strudinox
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I was really interested in this mod, so I spent the last week monitoring the voltage with the AP. During various driving conditions, including WOT, my voltage never dropped below 12. Usually between 12.5-14v.

I'm not sure that I am going to benefit a whole lot from this...
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Old 09-26-2016, 02:01 AM   #27
clark4131
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I just did the mod today, as I've been having fairly regular AP shutdowns. I monitored my voltage prior to the mod, and I was seeing drops consistently to the 11.3 range and occasionally to 10.8. After the mod, nothing below 13.5. I'm sold!...SC
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Old 09-26-2016, 11:16 AM   #28
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This is very interesting. This may explain why I had to replace my dead stock battery this past summer.
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Old 09-26-2016, 11:46 AM   #29
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i'll be doing this mod soon and check if there's any improvement
hopefully it won't have any issues with the alternator on the long run.
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Old 09-26-2016, 07:27 PM   #30
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Quote:
Originally Posted by jw4902 View Post
This is very interesting, my stock sound system gets louder sometimes on its own as if its getting more power than when I had set the volume. Maybe I was turning the blower fan up to high and that causes it. OP thanks for the info.
Are you listening to the radio when this happens or music from a phone/music player?

I've noticed that the stock antenna is not very great. It'll pick up "HD" radio channels and then it'll go back to standard definition quality a few seconds later and then back to HD. It's kind of annoying.
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Old 09-26-2016, 07:46 PM   #31
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Originally Posted by YungBoba View Post
Are you listening to the radio when this happens or music from a phone/music player?

I've noticed that the stock antenna is not very great. It'll pick up "HD" radio channels and then it'll go back to standard definition quality a few seconds later and then back to HD. It's kind of annoying.
I turned the HD radio feature off for this very reason.
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Old 09-28-2016, 07:57 PM   #32
Steve SAB HELI
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Guys I just did this last night..... I can definitely say that the car runs much better! the way that the throttle responds is a lot more crisp and consistent and no feedback knoc above the occasional -1.14. My car just seems way smoother and feels more stout in the lower mid range boost levels 5-10psi range. I can only describe this as how NA cars such as my Nissan sr20 engines picked up a snappier response when the EGR was disabled. Well worth a try. Car is 2016 STI factory exhaust. Prior to removal of wire the 12V rail would dip as low as 10V and when boost was on I had some -2.8 to -4.XX or so FBK until batt got back up around 13v or so.

Steve
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Old 09-28-2016, 09:12 PM   #33
boostingwrx12
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good to know thanks
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Old 09-29-2016, 10:59 AM   #34
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I was planning on doing this mod. I have a RD with voltage on the display so I have observed the ECU controlled charging behavior that seems to use three steps depending on conditions (somewhere around 12.5v, 13.5v, and 14.5v).

Because of this thread I started logging my voltage and I found it was stable at 13.5v during an entire WOT run.

So now I'm scratching my head wondering why we seem to have a range of differing results.
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Old 09-29-2016, 12:19 PM   #35
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Originally Posted by shadrag View Post
I was planning on doing this mod. I have a RD with voltage on the display so I have observed the ECU controlled charging behavior that seems to use three steps depending on conditions (somewhere around 12.5v, 13.5v, and 14.5v).

Because of this thread I started logging my voltage and I found it was stable at 13.5v during an entire WOT run.

So now I'm scratching my head wondering why we seem to have a range of differing results.
Supposedly, the ECM modulates the alternator output as a function of the emissions system, not as a charging plan. The more load you put on the engine, the less charge that goes to the battery, in theory, to decrease the amount of effort/gas/emissions the engine puts out to satisfy your right foot. Due to the nature of driving, these changes are very short lived and don't really serve to prevent global warming, but they do cause issues with the other electronics, especially peripheral aftermarket goodies like an AccessPORT. A true, multi-phased battery charging system goes through distinct phases that last a while, minutes to hours. I just wired in a 110 to 12v converter/charger system for a trailer with a deep cycle battery, and it has three phases, boost, normal, and storage, all of which take a while to cycle through. Our cars are definitely not doing this. In comparison with my other vehicles, the same is true. I have a much more constant voltage that never drops below the 13 volt range...SC
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Old 09-29-2016, 01:10 PM   #36
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Subscribed. I'll be keeping an eye on more results before I tamper with it. Nice work though.
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Old 09-30-2016, 06:04 AM   #37
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I had the same problem on my FXT. The issue is not the alternator not doing its job properly, its your battery. The OEM battery is just fit for purpose and barely last two years. If you have ever had a flat battery and couldnt start the car you can be sure its not holding up voltage when under load. Short story - your batteries are dead.

When cruising, the alternator cuts back its charging duty cycle to conserve fuel (as mentioned above). I used to see my OEM battery (Panasonic brand) drop to 10v at certain times but with the new battery, the minimum I have seen it drop to is 11.8. When you are rolling down a hill and lift the gas pedal I have seen charging current as high as 60 Amps when the alternator is charging 100% duty cycle. Another sign that your battery is not holding charge is a rough idle.

Get yourself a new super/ultra heavy duty battery and report back with your results.
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Old 09-30-2016, 09:20 AM   #38
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Originally Posted by danoz View Post
I had the same problem on my FXT. The issue is not the alternator not doing its job properly, its your battery. The OEM battery is just fit for purpose and barely last two years. If you have ever had a flat battery and couldnt start the car you can be sure its not holding up voltage when under load. Short story - your batteries are dead.

When cruising, the alternator cuts back its charging duty cycle to conserve fuel (as mentioned above). I used to see my OEM battery (Panasonic brand) drop to 10v at certain times but with the new battery, the minimum I have seen it drop to is 11.8. When you are rolling down a hill and lift the gas pedal I have seen charging current as high as 60 Amps when the alternator is charging 100% duty cycle. Another sign that your battery is not holding charge is a rough idle.

Get yourself a new super/ultra heavy duty battery and report back with your results.
I think you may be describing a different problem, as disconnecting the wire in question eliminates the voltage drop...SC
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Old 09-30-2016, 09:32 AM   #39
Steve SAB HELI
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So after having this past couple of days I can say that the car definitely runs 100% better . No rough idle (ever), throttle response is greatly improved and boost is almost equal now to the target boost . I mean that as i increase throttle the target boost displays for example 11psi the actual boost is now ~10.xx-11.xx where before the low throttle imputs 10%-25% or so the boost actual was always lower than the target. Now corrected increasing the low end TQ I can feel. Weird but true... I believe that Danoz is correct I may have a bad batt. I was really not so impressed with the cars throttle response before even with displayed boost pressure the car didnt seem to pull much harder if boost was say 14-15 psi or up towards 20. The higher batt voltage has really changed the car dramatically. Down side is gas milage has suffered a bit by 2-3 mpg. but this may be due to the fact i am dipping into boost a bit more now cause it is that much different than before. The car feels correct. Best is it has as I feel a deeper well of low end torque and idles as smooth as my 17 Maxima now. Funny thing is when new last year in Oct it felt good so may be indeed a weak batt.


Steve
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Old 09-30-2016, 09:38 AM   #40
Steve SAB HELI
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So after having this past couple of days I can say that the car definitely runs 100% better . No rough idle (ever), throttle response is greatly improved and boost is almost equal now to the target boost . I mean that as i increase throttle the target boost displays for example 11psi the actual boost is now ~10.xx-11.xx where before the low throttle imputs 10%-25% or so the boost actual was always lower than the target. Now corrected increasing the low end TQ I can feel. Weird but true... I believe that Danoz is correct I may have a bad batt. I was really not so impressed with the cars throttle response before even with displayed boost pressure the car didnt seem to pull much harder if boost was say 14-15 psi or up towards 20. The higher batt voltage has really changed the car dramatically. Down side is gas milage has suffered a bit by 2-3 mpg. but this may be due to the fact i am dipping into boost a bit more now cause it is that much different than before. The car feels correct. Best is it has as I feel a deeper well of low end torque and idles as smooth as my 17 Maxima now. Funny thing is when new last year in Oct it felt good so may be indeed a weak batt.


Steve
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Old 09-30-2016, 09:50 AM   #41
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Quote:
Originally Posted by danoz View Post
I had the same problem on my FXT. The issue is not the alternator not doing its job properly, its your battery. The OEM battery is just fit for purpose and barely last two years. If you have ever had a flat battery and couldnt start the car you can be sure its not holding up voltage when under load. Short story - your batteries are dead.

When cruising, the alternator cuts back its charging duty cycle to conserve fuel (as mentioned above). I used to see my OEM battery (Panasonic brand) drop to 10v at certain times but with the new battery, the minimum I have seen it drop to is 11.8. When you are rolling down a hill and lift the gas pedal I have seen charging current as high as 60 Amps when the alternator is charging 100% duty cycle. Another sign that your battery is not holding charge is a rough idle.

Get yourself a new super/ultra heavy duty battery and report back with your results.
Quote:
Originally Posted by clark4131 View Post
I think you may be describing a different problem, as disconnecting the wire in question eliminates the voltage drop...SC
It's not a different problem... it's the battery.

No matter how you cut it, if you see battery voltage that's too low... it is the battery, not the charging system. It is the battery, as loaded with nothing more than the running of the vehicle's normal systems a good battery will always show nominal voltage of +-12.5vdc.

The "new" battery in my '15 WRX was completely dead after leaving a map light on overnight. Ridiculous. I had the battery tested and professionally charged, but planned to replace it. However, once it was reinstalled it worked perfectly. It held full voltage at all times, charging was without criticism, and it never ever dropped below 12.5v regardless of how long it sat. Obviously, the battery had never been properly charged from the factory.

Either get a new and better battery or deep charge your OEM one on professional equipment if you have "voltage" issues. He's right, it's the battery, not the charging system.
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Old 09-30-2016, 02:39 PM   #42
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i've been watching this on my AP for about a week of city driving. almost always drops to around 11v when cruising, 12v at idle. i only have the radio on, no AC. i've left a light on accidentally and killed the battery once in this car, but i have not had any actual problems like my AP turning off. my windows go up at different speeds if i do them together though. i might do this mod this weekend.
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Old 10-04-2016, 01:58 PM   #43
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RESULTS!

So I've been following this thread brainstorming for awhile, and after reading around, I decided to call Cobb Tuning. Their support was amazing. I asked about the issue and confirmed that the AccessPort does indeed use voltage to detect if the car is on (for the WRX), and mentioned that it could potentially be caused by the ECM dropping alternator output voltage, which they agreed with. As well, I asked if they've tried using anything else (injector duty cycle, etc), and they said that yes, they've experimented with various parameters including RPM, but that occasionally the reading would become invalid, and the same thing would happen (AP turning off). I suggested that they use a culmination of parameters (voltage, RPM, etc) and conditionally tell if the car is off based on which ones show as being in a state that would indicate the car is off, that way any outliers (such as voltage when you're idling) could be mitigated for the most part, and interestingly enough, they said that they were actually looking at doing exactly that. No promises or guarantees, but they said they *might* be revisiting the auto-off feature after they finish with 2017 support to implement this

Again, Cobb support is amazing, I was surprised they were able to get so technical immediately.

To clarify, this *only* fixes the Access Port reboot issue. If your battery voltage is going low enough that you're experiencing any other issues, I think the previous person is right, it is indeed the battery. I watched the voltage on my AP and can see it drop in specific situations, but I've never had issues with anything but the AccessPort thinking the car is off.

Last edited by Trae32566; 10-04-2016 at 02:14 PM. Reason: Clarification
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Old 10-04-2016, 02:14 PM   #44
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On my 2017 my compressor for my airlift kit actually has dipped in power a bit at random times when I started driving while it filled back up.

It has never turned off or anything but I can confirm there is a weird power dip based on this behavior.
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Old 10-05-2016, 02:09 AM   #45
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Originally Posted by clark4131 View Post
I think you may be describing a different problem, as disconnecting the wire in question eliminates the voltage drop...SC
the battery should never drop below 11 volts under load. Its the battery 100%. trust me.
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Old 10-06-2016, 09:57 PM   #46
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the battery should never drop below 11 volts under load. Its the battery 100%. trust me.
This is a charging issue fix. Works on any battery you put in the car.....
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Old 10-07-2016, 12:15 AM   #47
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Originally Posted by scooby4u View Post
Many of you may have noticed the poor charging characteristics of the 2015 and up wrx's. The problem lies in the ECM's ability to control the alternator output to try and achieve better fuel mileage. The result is unfortunately a charging system that allows battery voltage to drop down to 10.1 volts at times.

This low voltage can cause any different issues. Some noted have been poor lighting, accessport rebooting, rebooting of power socket accessories, and much more.

In the video I've posted, I've included visual instruction as well as links to images for electrical system diagrams. Myself and some others have beta tested these systems and data collection and have found no notable negative side affects for allowing the system to operate in this way.

Please note that this is a reference only and performing wiring alteration should be done by someone with proper skill to do so. I do not take responsibility for any damage you may cause to your vehicle.

https://youtu.be/j4Hv4VKvygs
Thanks so much sir for your amazing help
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Old 10-07-2016, 02:22 AM   #48
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So I've been having problems as well. What I've noticed is when all accessories are off I have low voltage 10.5-11.8. Never noticed if the car drives different. After I turn it off battery is too low to start car.... Now if I run the car with headlights on it runs in the 13s at all times. And car starts crisp with no issues. So I can not drive my car with the lights off. So I'm curious to see if a new battery will fix my car. Also I never had these issues till I installed my accessport. Always wondered if that was my main cause. Or it's the car
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Old 10-07-2016, 06:49 AM   #49
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Originally Posted by YungBoba View Post
Are you listening to the radio when this happens or music from a phone/music player?
No I don't listen to the radio much. I've got 44 or so albums on a thumbdrive (or flashdrive) and usually listen to that so I don't have to listen to commercials. I guess I should check my battery voltage.
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Old 10-13-2016, 02:53 AM   #50
danoz
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A great tool to troubleshoot this issue is an Android ONLY app called "Active OBD". You will also need a bluetooth or wifi OBDII adaptor. The program is specifically for the current build WRX and Forester with the FA20DIT. Add the widget "alternator duty cycle" and "Battery current" then you will see what your charging system is doing. The alternator never STOPS charging completely but its duty cycle will drop under certain conditions and engine load.

If the system cannot maintain a battery voltage of 11.5 - 12Volts when the engine is running and the alternator is at its minimum duty cycle, at idle with all accessories off, then your battery is absolutely dead. Get a new one!

Like I mentioned before, I had all of the above symptoms you are experiencing. I thought to myself "There is no way my battery is the problem" I replaced the battery (for other reasons) and every symptom miraculously disappeared.
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