Charge controller and battery sizing question

Just being anywhere near/around the water is great for me!

The "Raw AH" rating of battery bank does set some limits on surge current capability (sort of maximum inverter and solar array support).

However Lithium, and to a degree AGM, are very good at surge even in smaller AH capacity (C/2 to even C*2 surge). And for some (like some of the LiFePO4), you have to look at their specifications--While the max/surge current of the basic chemistry is capable, the actual terminal/internal construction sets limitations, and so does (in Li Ion) does the BMS.

For Deep Cycle Flooded cell Lead Acid, they have less surge capability (C/2.5 max, and C/8 is a good max for maximum continuous draw).

For most people, it is your average energy usage (maybe 5 hours per night, for 2 nights of no-sun recharging/bad weather, 50% maximum discharge) drives the actual battery sizing--And usually, that AH capacity is "enough" for max inverter/surge for most installations.

And any "high surge/power loads", frequently have their "solar friendly" equivalent (such as Grundfos well pumps, "slow pumping" to tank, then local pressure pump, energy star appliances, etc.).

With an LiFePO4 type battery bank, their charging cycle is much faster and more "solar friendly" (high charging current until full--vs the 2-6 hour absorb cycle of FLA). And you can use the ~20-90% cycling capacity (~70%+ of capacity) vs the 40-50% of capacity of FLA batteries (for longer battery life). However, when you go to 20% SoC for Li Ion, that is it (genset or power off). Whereas, you can, on occasion, take a FLA deep cycle battery down to 20% SoC when needed (you do need to recharge quickly, with a genset, if needed back towards 80% SoC to not "kill" the FLA battery with sulfation).

In the end, knowing your loads, and picking "solar friendly" electrical devices are going to be a big help. To answer questions like what panels, what controller(s), etc. falls out after the "paper sizing" (back of envelope) design. You use those numbers when you select the actual hardware for phase 2 detailed paper design.

Just to say 100' from array to charge controller will work well with a "standard" 140-150 VDC max input charge controller, vs a 200 or 600 volt maximum input solar charge controller... Don't know until both phase 1 and 2 paper designs are done.

Other issues, your loads... If you have 12 VDC set of loads (like HAM radio)--Then 48 VDC is less interesting... If your AC loads are "smaller", then finding a good fit (smaller 48 VDC inverter with the "features you want" could be an issue--Although, there seem to be a lot more smaller 48 volt AC inverters in the last few years available).

Sorry, no real answers. But hopefully it helps you taking steps forward.

-Bill