What do the numbers mean?

[stockhorse]

I am at a loss as to working this out as sales people seem to be able to baffle me every time.

A battery is marked as an ns50pl 450 cca, rc min 75.

So cca is cold cranking amp but what is rc min 75?

Also when I look up the ns50pl on the net to compare prices they all say 520cca and rc min 90.

Thanks for the help.

[Not_An_Abba_Fan]

RC is reserve charge. This is how long the battery will last before it goes flat at the rated amp hour draw. RC min 75 means it should last for 75 minutes.