Max volts is whatever the controller's max volts is***. I don't recommend running at that as it gives you no headroom for regen or other voltage spikes or increases. Whatever the typical nominal voltage for the controller is would be safer.
***assuming you have no other devices that connect to the battery, like a cycle analyst, smartcable, DC-DC for lighting, or other accessories...if you do, then the lowest-rated item is your max voltage limit, and again, staying farther below that gives more safety headroom.
Max Ah is whatever your volume and weight limit is for you and/or your vehicle divided up by the volume/weight of the batteries you intend to use vs their Ah capacity.
We can't know how many batteries you can put in p or s because we have no way of knowing which batteries you have.
The more detail and specific information you provide, including links to the sale pages for the specific item versions you already have and the ones you are considering buying, the more likely it is we can help.
