E90Post
 


 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > AUDIO/VIDEO + BLUETOOTH + Electronics/Alarm/Software > Connecting amp to battery



Reply
 
Thread Tools Search this Thread
      07-17-2012, 11:59 AM   #1
kskjon
New Member
3
Rep
10
Posts

Drives: 2011 E90
Join Date: Jul 2012
Location: Norway

iTrader: (0)

Connecting amp to battery

I had a talk with my dealer today about connecting an amp to the distribution block on top of the battery.

According to the dealer, I shouldn't do that since the car monitored the power outputs and power usage, and might give error messages or worse if it detected anything out of the ordinary.
They had a scare story about someone they knew who had fried their stereo trying this.

Is this true, or is my dealer talking hogwash?
I have a 2011 E90 with standard Professional stereo (no Logic 7 or idrive)
Appreciate 0
      07-17-2012, 12:15 PM   #2
Technic
Lieutenant General
Technic's Avatar
2258
Rep
12,985
Posts

Drives: 2021 i3S, 2024 i4 M50
Join Date: Apr 2005
Location: Florida

iTrader: (18)

Quote:
Originally Posted by kskjon View Post
I had a talk with my dealer today about connecting an amp to the distribution block on top of the battery.

According to the dealer, I shouldn't do that since the car monitored the power outputs and power usage, and might give error messages or worse if it detected anything out of the ordinary.
They had a scare story about someone they knew who had fried their stereo trying this.

Is this true, or is my dealer talking hogwash?
I have a 2011 E90 with standard Professional stereo (no Logic 7 or idrive)
Each distribution block slot either has a fuse or not. So in the worst case the OEM fuse will be blown in case of a short of the device connected to that slot. And that's only if the device own fuse does not blow first.

That is a much better option than connecting a device directly to the battery post, IMO.
Appreciate 0
      07-17-2012, 01:12 PM   #3
ctuna
Lieutenant General
1904
Rep
13,088
Posts

Drives: 325xi 06 wagon MT
Join Date: Jan 2010
Location: Santa Cruz, Ca

iTrader: (0)

I think its safer to go to the tightening lug bolt

I think its safer to go to the tightening lug bolt
That way the possibility of blowing the fusible links is zero.
Most of the time when the fusible links have been reported
blown here its due to a bad ground.
Plenty of people have done it both ways and they usually don't
come back here saying they have problems .
The trouble with the fusible link is I don't see how you know
what they are rated at and and some cars have limited active
slots with blades you can attach to.

Last edited by ctuna; 07-17-2012 at 01:24 PM..
Appreciate 0
      07-17-2012, 03:36 PM   #4
Technic
Lieutenant General
Technic's Avatar
2258
Rep
12,985
Posts

Drives: 2021 i3S, 2024 i4 M50
Join Date: Apr 2005
Location: Florida

iTrader: (18)

Quote:
Originally Posted by ctuna View Post
I think its safer to go to the tightening lug bolt
That way the possibility of blowing the fusible links is zero.
Most of the time when the fusible links have been reported
blown here its due to a bad ground.
Plenty of people have done it both ways and they usually don't
come back here saying they have problems .
The trouble with the fusible link is I don't see how you know
what they are rated at
and and some cars have limited active
slots with blades you can attach to.
The fuse rating is printed on each OEM fuse.
Appreciate 0
      07-18-2012, 05:12 AM   #5
kskjon
New Member
3
Rep
10
Posts

Drives: 2011 E90
Join Date: Jul 2012
Location: Norway

iTrader: (0)

Quote:
Originally Posted by ctuna View Post
I think its safer to go to the tightening lug bolt
That way the possibility of blowing the fusible links is zero.
Most of the time when the fusible links have been reported
blown here its due to a bad ground.
Plenty of people have done it both ways and they usually don't
come back here saying they have problems .
The trouble with the fusible link is I don't see how you know
what they are rated at and and some cars have limited active
slots with blades you can attach to.
Which one is the lug bolt?
RealOEM


Also, is it safe to disconnect the battery from the car?
Appreciate 0
      07-18-2012, 08:11 AM   #6
Jose_JN
Private First Class
Jose_JN's Avatar
Spain
88
Rep
186
Posts

Drives: e93 330d
Join Date: May 2011
Location: http://www.youtube.com/josejjn

iTrader: (0)

You can disconnect the battery without problems.

Don't damage the thin wires, they monitor the battery status and the pyrotechnic cut system!

I don't know why you shouldn't connect an amplifier directly to de battery... The Apline HiFi Retrofit System is connected directly to the battery using the original nut.

Regards
__________________
Why don't do it by your self?
Retrofitting is always possible!
Appreciate 0
      07-18-2012, 10:33 AM   #7
808MGuy
Colonel
808MGuy's Avatar
218
Rep
2,339
Posts

Drives: 2009 E90 M3
Join Date: Jun 2008
Location: Oahu, Hawaii

iTrader: (3)

I had mine connected through the fusible link when I had only 1 amp. When I added a second, I decided to move that connection to the main terminal before the distribution block because I wasn't comfortable connecting that much load to the fusible link. Never had problems either way.
__________________
2016 Porsche Cayman GTS - Sapphire Blue / Black Full Leather Interior / Carrera S Wheels
Appreciate 0
      07-18-2012, 11:01 AM   #8
ctuna
Lieutenant General
1904
Rep
13,088
Posts

Drives: 325xi 06 wagon MT
Join Date: Jan 2010
Location: Santa Cruz, Ca

iTrader: (0)

In the picture 2 is the tightening lug bolt or terminal bolt

In the picture 2 is the tightening lug bolt or terminal bolt.
Its the same for the other terminal but its under a plastic cover that
needs to stay up when the connection is in place.
After you remove the nut you have to make sure the end of the battery cable is all the way down on the battery when tightening or it won't tighten.
Appreciate 0
      07-18-2012, 12:47 PM   #9
kmarei
Major General
kmarei's Avatar
Egypt
685
Rep
6,844
Posts

Drives: 2018 Audi RS5 coupe
Join Date: Jul 2008
Location: Reston, VA

iTrader: (34)

Garage List
2018 Audi RS5  [0.00]
here are some pictures of the fuse panel, i have a spare one.
Now i know i can use the last unfused terminal so i don't run the risk of blowing the OEM, and since i am using my own fuses later on

Top



Cover removed (I wrote the values that were stamped into the metal, couldn't get them on the camera, i assume those are amp ratings)



__________________
Appreciate 0
      07-18-2012, 01:43 PM   #10
taibanl
Brigadier General
taibanl's Avatar
279
Rep
4,121
Posts

Drives: BMW
Join Date: Sep 2010
Location: NA

iTrader: (4)

I run three independent lines for each of my devices. I ran each of my (already fused) lines to a slightly higher rated fusible link, to protect the car just in case the lines short out somewhere.

FWIW There is no electrical difference between using the unfused port at the end of the block and the lug directly.
Appreciate 0
      07-27-2012, 02:21 PM   #11
kskjon
New Member
3
Rep
10
Posts

Drives: 2011 E90
Join Date: Jul 2012
Location: Norway

iTrader: (0)

Thanks for all the help!

I've connected a PAC SOEM-T to the rear speaker wiring, and ran a 12v directly from the battery terminal (not the distribution block).
I've connected the amp to the battery as well, but i haven't connected it to the sub.
I grounded it to one of the screws under the "false floor" in the trunk. There is 12.7v between the screw and the positive terminal with the engine turned off.

The problem is, I get a ton of static in my speakers when I switch it all on. The static disappears if I switch the fuse off. (I got a 100A rockford fosgate automatic fuse)

I also seem to have the opposite problem of other PAC owners. The remote wire from the SOEM-T is always live as long as it has power.

Edit:


Not everything is connected in the above picture, but it should show most of my connections. The SOEM-T is connected to the speaker wires hidden behind the left side shoulder support.
It is also grounded to the grounding connector behind said shoulder support.

The "permanent live" connector to the SOEM-T is connected to 12v positive on the amp.

Last edited by kskjon; 07-27-2012 at 03:14 PM.. Reason: Added info/picture
Appreciate 0
      07-27-2012, 03:28 PM   #12
bmw325i
Major General
223
Rep
5,119
Posts

Drives: 2006 BMW 325i
Join Date: Oct 2010
Location: United States

iTrader: (8)

You should use the signal from the underseats since the rear speakers are high passed. You should also get a better line output converter or better yet Technic's harness. Ground your amp to the battery, or where the battery is grounded to if your ground is long enough.
Appreciate 0
      07-27-2012, 04:28 PM   #13
808MGuy
Colonel
808MGuy's Avatar
218
Rep
2,339
Posts

Drives: 2009 E90 M3
Join Date: Jun 2008
Location: Oahu, Hawaii

iTrader: (3)

Where is the fuse for your +12V wire to the amp? I don't see one in the picture.
__________________
2016 Porsche Cayman GTS - Sapphire Blue / Black Full Leather Interior / Carrera S Wheels
Appreciate 0
      07-28-2012, 08:31 AM   #14
kskjon
New Member
3
Rep
10
Posts

Drives: 2011 E90
Join Date: Jul 2012
Location: Norway

iTrader: (0)

Quote:
Originally Posted by 808MGuy View Post
Where is the fuse for your +12V wire to the amp? I don't see one in the picture.
It's directly behind the battery, glued to the "wall" underneath the cover for the rear lights
Appreciate 0
      07-28-2012, 08:33 AM   #15
kskjon
New Member
3
Rep
10
Posts

Drives: 2011 E90
Join Date: Jul 2012
Location: Norway

iTrader: (0)

Quote:
Originally Posted by bmw325i View Post
You should use the signal from the underseats since the rear speakers are high passed. You should also get a better line output converter or better yet Technic's harness. Ground your amp to the battery, or where the battery is grounded to if your ground is long enough.
Are they high passed on non logic 7 systems as well? (I don't have logic 7 or an original external amp)

Edit
I don't have front tweeters either

Last edited by kskjon; 07-28-2012 at 09:45 AM.. Reason: Additional info
Appreciate 0
      07-29-2012, 10:06 AM   #16
kskjon
New Member
3
Rep
10
Posts

Drives: 2011 E90
Join Date: Jul 2012
Location: Norway

iTrader: (0)

It definitely looks like a ground problem.

I moved the ground for the SOEM-T and disconnected the amp remote wire, and the static disappeared. It also looks like the remote turn on started working.
However, the static slowly returns (after 5-10 seconds) if I turn on the amp.
I haven't moved the amp ground yet. I need a longer ground cable first.


Edit:
Heres a photo of the battery wiring/fuse:


Last edited by kskjon; 07-29-2012 at 02:01 PM.. Reason: Added photo
Appreciate 0
      07-29-2012, 02:05 PM   #17
kskjon
New Member
3
Rep
10
Posts

Drives: 2011 E90
Join Date: Jul 2012
Location: Norway

iTrader: (0)

Where's the best place to hook up to the underseat sub wiring?
Does the wiring go under the door sills?
Appreciate 0
      07-29-2012, 02:26 PM   #18
ctuna
Lieutenant General
1904
Rep
13,088
Posts

Drives: 325xi 06 wagon MT
Join Date: Jan 2010
Location: Santa Cruz, Ca

iTrader: (0)

Yes wiring comes out from the sills

And plugs in at the speaker on a connector .
Appreciate 0
      07-31-2012, 02:14 PM   #19
kskjon
New Member
3
Rep
10
Posts

Drives: 2011 E90
Join Date: Jul 2012
Location: Norway

iTrader: (0)

... just in case someone wanted to see how the woofer enclosure worked out



It's not perfect, it's my first ever attempt at molding fibreglass.

I've put in a longer ground cable today, but I need to get a ring connector for it. Will do that tomorrow.

Last edited by kskjon; 07-31-2012 at 02:22 PM.. Reason: Spelling
Appreciate 0
      07-31-2012, 02:58 PM   #20
ctuna
Lieutenant General
1904
Rep
13,088
Posts

Drives: 325xi 06 wagon MT
Join Date: Jan 2010
Location: Santa Cruz, Ca

iTrader: (0)

For a sub in the back I would run new wiring.

For a sub in the back I would run new wiring.
Appreciate 0
      08-01-2012, 11:01 AM   #21
kskjon
New Member
3
Rep
10
Posts

Drives: 2011 E90
Join Date: Jul 2012
Location: Norway

iTrader: (0)

I've run a new ground cable directly from the battery to the amp. The 12v to the SOEM-T is now connected to the same as the amp.

It looks like the static is only when using radio as a source. It disappears when using aux.

I'm guessing something interferes with the FM antenna.
Appreciate 0
      08-01-2012, 02:44 PM   #22
kskjon
New Member
3
Rep
10
Posts

Drives: 2011 E90
Join Date: Jul 2012
Location: Norway

iTrader: (0)

Everything seems to work perfectly as long as the engine is running.
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 11:07 PM.




e90post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST