Wrong new alternator or bad voltage regulator for 4.8is

[ImolaRed48]

Hi, first post so apologise if doing anything wrong..

I bought an Imola red 4.8is recently whoch I love and will post pics.

Recently had to dive in to the nearest garage for a new alternator.

They installed a Delco Remy dra0488 Remanufactured - after being told they would source ans original Bosch - and charged me £600 for this including £55 for 1 hours labour)

Recently won't start always as it drops below 10v and sometimes below 12 whilst driving, other times it hits 18v after flooring it a few seconds. Then I'll stop at traffic lights and it will show 11v.

Luckily I have a Seuoki 2000amp jump starter of Amazon - recommended for these big engines!

Had to put in a new battery a week after this new alternator, however it was on its way out anyway.

Thoughts please on this exact model of alternator etc?

Many thanks..

[electricalserv x5]

Sounds like You should've bought a OEM from BMW it the same price......

[ImolaRed48]

I would have loved to but garage round the corner promised they would source the OEM in 2 hours then it was driven there with battery pack under the hood. Whats done is done.
I'm confused whether this alternator should even be in this model, nevermind if it's OEM. It might possibly be the voltage regulator instead?
I'm not completely sure about the correct voltage but I've read various posts ranging from 12 to 14v. I can see it constantly fluctuating with a voltage reader.

[OnTouring]

I’d check the voltage regulator. Had the fluctuating voltage while driving (Valeo), it got bad enough to drop under 8V and trigger engine failsafe- not fun.

Tried the new voltage regulator, been steady voltage ever since.

The brushes get worn and don’t make constant contact- hence the fluctuation.