Understanding amps role through a vehicle system

[UncleTodo]

So one aspect I'm finding a little mystifying, amps and component selection.
Charger amperage selections, the rated amperage is what it can put in to the battery, and as well take from the alternator.
So for this it needs to fall within charge specs for the battery, and available alternator output.

BMS, seems charging current is typically half of the discharge current, so lets say I have a 30a charger, would I be safe to look at a BMS with 60a/30a discharge/charge?
How does this play into an inverter wattage selection? (FYI, 700w would meet my minimum needs, so I figured doubling it should be safe, so 1500w).

Thanks, I'm trying to find a good match of components while not underbuying, or overbuying, hopefully just right buying being on a budget.
Plus I'd love to have a better grasp how they interconnect.

 

[DThames]

Work from one end of the system to the other. For example you want a 1500w inverter. Assume this is a 12v system.

1500w/12v=125 amps. So fusing and cables from battery to inverter need to handle 125amps or more. Oversize a little here, so say 150a. That would be for surge. Will the BMS output handle a 150a surge? Make sure it does or be happy with its limits. Will your batteries deliver 150a without issues? What is the charging limit of the battery? Make sure your charger will not exceed what the battery can take. Will the BMS allow this much current? Depending on your charger power source, the power source might be the limit so battery charge limit and BMS charge limit would not be as critical. Anyway, look at each item, decide what you want.

If my battery will take 100amps but I only want to put up enough panels to deliver 30 amps, then I can size for 30a if I am sure I will not change my mind later. If my panels and charger will deliver 50a but my BMS will only take 30 for charging, then I better change something.

 

[UncleTodo]

Thanks DT, that helped quite a bit. I was thinking along those lines and confirmation was great.

 

[UncleTodo]

Actually, one more question about calculating charge time.
Certainly a 50A charger would charge faster than a 30A, but how much faster?
Maybe saving $50 on a charger is worth an X minute longer charge...