I've been researching too and everyone is saying white/clear batteries are lead acid, black are AGM
Originally Posted by SteVTEC
Just wanted to follow up here.
Had my SA look at the part number and it wasn't an AGM that they put in. He said he's only ever seen the part number suffix that indicates an AGM type battery on cars like the 650i maybe? So it's a regular type battery they put in our E9x's. Cold out so still using snowflake/AGM mode but will switch to regular mode when it warms up.
I can tell the difference between a fully charged and a weaker battery by the servo motor to pop the trunk. It's noticeably faster and higher pitched after fully charging the battery! It's slower and lower pitched when the battery is lower. I should dig out my old multimeter and put it across the jumpstart hookups in the engine bay so I have something a little bit more scientific.
The CTEK 7002 failed to make any significant difference after reconditioning my three year old battery. Dealer failed several times to fix the issue so I bought and fitted a new battery (bought from a local AutoZone). The rough running when cold has not reappeared and it drives great (only two days since the new battery so far but it seems cured)
Going forward with the car I'll use the CTEK when storing the car for extended periods (it's a 3rd car)
With hindsight I should have just put a new battery in weeks ago and bought any old trickle charger for use going forward. I hope to use the original battery for a solar power project and hopefully Epsom Salts + few more CTEK recondition runs will bring it back to significant life
Six Euro Deliveries since December 1998 (Owned E46, E90, E91, E92 and E93)
28 vehicles in 26 years of driving so far. Guess I like cars