So I just changed my battery for the 3rd time this year. Yeah, I dunno. Im not driving the Mini (2014 MCS manual) as much and after sitting for just over a 1.5mo the brand new batteries just seem to crap out. Its weird because when the car was much newer I'd sometimes leave it sitting for 2-3 months and it would start right up. But, now at 11 years old it seems to want to eat batteries unless driven often. Parasitic loss somewhere perhaps or just old car being an old car?

Anyhow!
The reason for this post is that as I replaced the battery today and bolted on the battery cables I noticed that one of the cables was a bit frayed (See pics). It starts right up with the new battery but the frayed cables worry me a bit. Should they or is it fine if a few are frayed out like that?

EDIT: in case this helps anyone out one day, my AC fan wouldn't blow very hard any more, really not much more than a "low" setting even when set to max. I was worried the AC compressor or so was going. However, when I put in the brand new battery the AC came back to life! I never knew a bad battery affected the AC system but posting this here in case anybody has similar symptoms.

 

I would look in to replacing that cable.

As for the car discharging the battery - something is draining the battery while sitting. Lead acid batteries are not designed to be discharged completely, and when you do it reduces the life cycle of the battery. You should look in to installing a different type of battery that handles discharge better, and also are you registering the battery with a scan tool? It's my understanding that the car doesn't charge the battery at the same rate dependent on the 'life cycle' of the battery, which requires you to input that data in to the vehicle when changed.

 

Did you register the new batteries to the car??