2/12. The old one was the OEM, i got another OEM battery. I replaced the old one because the temp gauge would stay off or rise very slowly on cold start. It's the same as BMW when the battery gets low, the cars freak out. Anyway, it's done the same thing with both batteries. Cold starts are just fine, starter sounds good. If i've been driving it at temperature, then i shut it off to go inside for maybe 15-30min, i come back out and it sounds like the cranking is slower than normal. It always fires no problem, it's just that sound of the starter working a bit harder.How old is your battery?
Sounds about right, just wanted to see if anyone experienced the same result as me. The wife's '01 C70 T5 doesn't seem to do it, but im not sure if it's the same part number as the R...i would seriously doubt that.The armature in the starter can swell slightly during a heat soak, and cause binding on the field winding. This results in slow crank speed.
Also the solenoid armature, (plunger) can do the same thing, however this will result in a no crank scenario, and a good whack on the starter will free it up.
A new starter may be in your future, meanwhile check wiring at battery and starter.