[david in germany]

Originally Posted by ctuna

I have had my amp connected up to my battery terminals
with eyelet connectors for years. And this was recommended
and supplied by MusicarNW a major west coast high end shop.
One thing you should do is check your ground with an ohmeter
and be sure you have no voltage drop between the battery and
your equipment.

You got lucky brother. I wasn’t so lucky.

[mweisdorfer]

Originally Posted by david in germany

You got lucky brother. I wasn't so lucky.

Originally Posted by david in germany

You got lucky brother. I wasn't so lucky.

I'm gonna use the left fender top ground point. I'll undo the bolt & slide the ring mounts of both the JBL MS-8 & the JBL 2 Channel amp I plan on using for the subs, and then clamp in back down. The 2 Channel amp is only 70watts a Channel at 2ohm.

[ctuna]

I don't think it was a matter of Luck every MusicarNW system
is grounded this way. And they are award winning pro installers.

[david in germany]

Originally Posted by ctuna

I don't think it was a matter of Luck every MusicarNW system
is grounded this way. And they are award winning pro installers.

I do agree with the majority of your post but this is one we will disagree on. The IBS is a very important measuring device for our electrical systems and to bypass it is a mistake.

Also (my opinion) just because you may be able to install an amazing sounding system does not mean your car will continue to operate optimally.


Do I agree with you on the fact that you will most likely get the most stable voltage for your amp at the battery? YES. 12v systems tend to operate by pulling through ground so the larger more stable grounds are always better. Think old school BIG 3, they always had more stable power. In our case, we have to take a hit to ensure our VERY sensitive electrical system stays working as it should and one of those very important sacrifices is not jacking with the IBS. On a very positive note though, BMW put a huge ground bolt 10-12" from the battery where the IBS connects to the body, use it!

[ctuna]

They don't bypass the IBS its plugged it's undisturbed.
Electrically attaching at the battery terminal is no different
than chassis grounding if the chassis grounding is non resistive

https://www.e90post.com/forums/attac...3&d=1329017429

see page 10 in the above (I think that is the battery picture)

[david in germany]

Originally Posted by ctuna

They don't bypass the IBS its plugged it's undisturbed.
Electrically attaching at the battery terminal is no different
than chassis grounding if the chassis grounding is non resistive

https://www.e90post.com/forums/attac...3&d=1329017429

see page 10 in the above (I think that is the battery picture)

Correct, but for the power transfer.

As for the pic, yes it shows the battery but not the ground connection to the battery lug as it states in the caption.

As I mentioned before, they may do it but it does not make it the right way to do it in “our” cars.

[ctuna]

It is connected.
I was showing somebody what the BSD connector
looked like in this picture.
The right way to do it according to BMW would
be to never add anything to your car.

[david in germany]

Exactly how I ran mine until my start stop started to act up and a couple of other power issues started to pop up, read out the codes and determined the IBS had failed. I moved the grounds to a chassis ground, replaced the IBS and all is good since. This was in my e87 so maybe the IBS is more robust in the e90? Lol nope same part number.

Edit to say, maybe I just have the crap luck with my cars.. my wife’s e90 got unstable after the performance brake upgrade and REQUIRED the retrofit coding, my IBS died when I bypassed it for amp grounding.. Anyone want to test an idea to see if it will fail?, shoot me a pm.. lol