Solar Build Questions

Okay. I'm starting to feel I have a grasp on this solar concept.
I do have a couple quick questions.
Negating the fact that i will obviously have to do a calculation to exactly how many amps I am using during a full day I want to pose a hypothetical.
If I got 4 hours of sun each day (theory) and had 500 AH's of batteries. What would I need for solar to charge those batteries if they were say just above the low voltage disconnect.
Reason for asking? I am looking to be completely sustainable on my boat regardless of my situation. the goal is to overbuild so that I have several days of batteries in case there is no sun, but can recharge in one day.
Thank you

Assuming 12.8v battery?

(500ah / 4h ) x 12.8v = 1600w solar at 100% efficiency

Wait. Is the math really that simple? Why have I been confusing it and making it harder than it is?

LostDog88 said:

Is the math really that simple?

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Its simple when you get the units correct and use ohm’s law.

500ah x 12v = 6000wh ( assuming lithium with 100% DoD)
if you are using AGMs, your useable capacity is more like 3000wh

Like above thats about 1500+W of solar panels at 100% capacity for 4~ hours

you have to take into account summer and winter though. thing with solar is that the setup to generate enough at the winter, will over generate in the summer

x4dow said:

assuming lithium with 100% DoD

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Yes, good additional info.