Installing a Subwoofer in BMW 128i (E82) – Alpine R2-W12R + S2-60M – Wiring Questions

[christian_128i]

Hey everyone,

I’m installing a subwoofer in my BMW 128i (E82) and wanted to get some advice before I start wiring everything.

I’m located in Canada and unfortunately most local audio shops wanted a pretty crazy amount for labor to build/install a setup like this, so I decided to order one from the UK and install it myself.

Current setup:

- Custom fiberglass subwoofer enclosure that sits flush in the trunk (similar to the one in the photo)

- Alpine R2-W12R4 12" subwoofer

- Alpine S2-60M mono amp

- Planning to run the sub at 600W RMS at 2ohms

- Android head unit with RCA outputs

- Remote wire from the head unit to turn the amp on (or should I tap into factory amp, and/or cigarette lighter?)

A couple wiring questions:

1. My backup camera is currently connected to the positive terminal of the battery in the trunk.
Is it okay to stack another power ring terminal for the amp on the same battery post, or should I be using something like a distribution block instead?

2. For the amp ground, I’ve seen a few different approaches:

- Some people run both positive and negative directly to the battery

- Others ground the amp to the chassis somewhere in the trunk (wire brush the paint off and bolt it down)

Is grounding to the chassis the better approach for this car, or does it not really matter?

3. Anything else I should watch out for installing this setup in an E82?

I attached the setup that inspired my enclosure.

Any advice from people who have installed subs in these cars would be appreciated!