Battery capacity

[dvici]

Hello,

Since I first bought my car back in february I've noticed that the engine takes quite a few cranks to start since I press the engine start button. The car battery has the following characteristics:
- 74 Ah
- 680 A (Cold cranking power)
- Regular battery, no AGM.

Do you think I should upgrade it for a bigger capacity battery??
Car is driven only once or twice per month and doesn't have any equipment (not even idrive, no start-stop function). It's a 2007 e92 6MT with only 64k km (40k miles).

Let me know your thoughts. Thanks for your help!

[roastbeef]

buy a battery tender.

[dvici]

Thanks for your answer. I've already have one, but to be more specific, is the battery CCA enough for this engine?
I got the car with this battery and my feel is that it isn't suitable for this car...

[pbonsalb]

If the battery is fairly new it should be fine except maybe in very cold weather. You can have it load tested. The size you have is about 15-20% weaker than stock but should still be sufficient under most conditions.

Consider replacing your engine ground strap. Test the ground first by using jumper cables as extra grounds. Attach them bare metal to bare metal and see if the engine cranks faster. After that I would suspect the starter motor.

[deansbimmer]

Generally, these cars are fitted with Group 49 size batteries which are around 900CCA. Your 680 is OK for the job if in good condition but if your engine cranks slowly then it's probably not and should be tested.

And yes, the car should stay on a tender if you don't drive it regularly.

[dvici]

Thanks! I will check the ground cable during the weekend. I will add the battery upgrade to the bucket list since I can see it shouldn't be a priority.