96 E38 728I M52 Minimum Battery Specs

[GrandClam 1]

Hey Guys

So I have a 728I E38 and I'm wondering what the minimum battery requirements are.

Everything online is saying e38s need the 110AH 850CCA batteries but most e38s are v8s and v12s mine is a straight 6 M52 motor and i can't find anything specific on that.

if those requirements above are for the v8s and v12s then its probably a bit overkill for a straight 6 engine no?

cheers for any insights here.

[gjm 3258]

V12 can have a smaller battery.

725TDS, 728I+IL, 730D, 730I+IL, 740D, 740I+IL, and 750I+IL are specified to have a 90Ah battery, BMW p/n 61217604822.

[GrandClam 1]

8 hours ago, gjm said:

V12 can have a smaller battery.

725TDS, 728I+IL, 730D, 730I+IL, 740D, 740I+IL, and 750I+IL are specified to have a 90Ah battery, BMW p/n 61217604822.

thanks for the reply. and what about the 850CCA spec? is that one also necessary? seems like the page you link doesn't mention that anywhere. I hear e38s are very finnicky with voltage and current and stuff.

[gjm 3258]

850CCA refers to 'Cold Cranking Amps'.

CCA is a rating used in the battery industry to define a battery's ability to start an engine in cold temperatures. It refers to the number of amps a (nominally) 12-volt battery can deliver at 0°F for 30 seconds while maintaining a voltage of at least 7.2 volts.

Your car may *need* this. Or it may not. It's not irrelevant but is of less importance (to you, in NZ) than the overall capacity and specification of the battery for your car. When was the last time you saw -18C when trying to start your car?

You'll probably find batteries meeting the specification of the BMW part number I quoted will exceed 900CCA.