Which battery is the crank battery?

[Hemmy]

I am joking up a prosport battery charger. It is the dual bank. Directions say to hook one of the banks to the crank battery. I have a 17 21 VLX. How do I know which battery is the crank battery? Thanks in advance.

[MLA]

Are they both the same type as in both cranking, both dual purpose or both deep-cycle? If they are both the same and your switch is a 1/2/BOTH, then they both are the cranking bank, they are also both the house bank,. You can take your pick and designate which one you want to be the primary cranking.   

[Hemmy]

I have 2 cranking batteries. Charger is hooked up. Thanks for the help @MLA.

Edited April 20, 2019 by Hemmy