[Danny H]

Hi,

I have recently bought off a friend a 2008 e93 320i with optional auto/stop start function and brake energy regeneration.

The battery was changed in November 2022 and I am 100% that the garaged didn't register the new battery.

It is an Exide AGM 95Ah EK950.

I always turn off the stop start function every time I drive (I hate it).

I don't have any problems with the battery going flat.

A few questions:

1) Should I register the battery now? or is it too late?

2) Is the capacity of the battery the same as the one originally supplied with the car? If not should I be recoding it?

3) Is it possible that the unregistered battery and brake energy regeneration could be impacting the radio reception? I intermittently get weak FM when the roof is down, but it generally seems to happen when I lift off, which I understand is usually when the battery charging kicks it.

Thanks in advance

Danny

[wrongmark]

My 320i E90 LCI came with a 80Ah battery from the factory.

1) Probably too late to bother registering the new battery, but how do you know it hasn't been done? If you know someone with Bimmerlink, it's easy to check.
2) Mine came wth an 80Ah from factory (2011 320i with stop start). Strictly, it should be coded to the new capacity (90Ah is the closest option anyway) and then registered.
3) I think 'brake energy regen' (or whatever they call it) just means the alternator has a clutch to only charge on deceleration. Can't imagine this would impact FM signal unless paired with a loose connection somewhere. Don't know where the antenna is on an E93, but mine on the E90 needs the contacts cleaning.

Hope this helps.

[Danny H]

Hi,

I have found 3 boxes (transformers / amplifiers?) in the roof pillars that appear to be connected to antennas, and also the diversity unit in the boot (behind the ns trim panel). The antennas behind the rear bumper look undamaged.

I can't see anything obvious and have checked all connections are clean.

Not sure sure if this helps, but I have noticed that with the roof up the AM reception improves massively when the lights and/or heated rear window are turned on.

Could I be suffering with a bad earth connection somewhere - any ideas welcome

Thanks

Danny

[wrongmark]

I’m sure there’s a DIY somewhere on here about cleaning the contacts for the diversity antenna. Mine is connected to the lines of the rear glass. I would start there but definitely look up the DIY that someone posted.

[Danny H]

Hi,

I think I might be getting to the bottom of my poor radio reception.

My car has LED angel eyes and daytime running lights (which have been turned on since I got the car a few months ago). I turned them off and the reception seems much better. It was too wet to try with the roof down today.

It also has LED number plate lights.

It's a 2008, built in November 2007, so I'm guessing these have been retrofitted?

If they are the cause is it just because they are poor quality bulbs?

Thanks

Danny

[Danny H]

Hi,

Final update on this, my signal was now only weak when the roof was down.

My diversity module was faulty. Nothing showed up in INPA or ISTA, so I tried a used one off eBay and the problem was solved.

I also checked my battery coding and it's set to an AGM 90Ah, but there is no record of any battery changes ever being registered, and I know the previous owner had two fitted.

Danny