SurePower combiner / Charger questions

Trying to get an answer here to a couple of hopefully easy questions...

1.) SurePower makes 2 models, a 1314 and a 1314-200. What do the amperage ratings refer to? Current drawing from equipment or alternator charging rating? How do I tell which one I need? My alternator is rated for 100 Amps but I also have 3 big amps sucking down power.

2.) What is the big difference between chargers that have different current ratings? If I get a smaller charger (like a 20 Amp) instead of a larger charger (like a 40 or 60 amp), does it charge the same, but just slower? I will always have 14-18 hours (worst case) charge time.

Thanks,

Chad

Amperage rating is for alternator output. Might as well go for the -200 model as it isn't much more expensive and leaves you room to upgrade.

Correct on the charger. Higher rating for faster charging.