Two day charging cycle rather than one day?

[sternwake]

My system is basically set up to do this with the flip of 2 or 3 1/2/both/off switches, and I used to do that occassionally when battery 2 needed to be equalized via solar, so I would switch all loads to battery 1 before sundown so that the next day battery 2 would start out nearly fully charged so the solar could achieve 16.2 v and hold it for as long as required for specific gravity to approach 1.285.

But I no have a battery hooked to 'battery 1' anymore

I used to have 345 AH of total battery capacity, 230 as battery 2 and 115 as battery 1.

From june 2015 to december 2019 I had only one 90Ah AGM battery as battery 2, and no battery 1.

I don't think I will ever have a battery 1 again, but things could change, I am keeping the wiring as it is if that day does come.

Remembering to turn the switches is an issue and switches do wear out and become more resistive, no matter how well they might be built

I much prefer to cycle one high$$ battery deeper than 2 or more lesser batteries shallower. I rather have higher charging amps available and a battery which is not going to be unhappy being forcefed huge recharging amperages.

batteries above ~80% state of charge limit how much amperage they can accept and turn some excess into heat, where below ~80% charged there is little loss to heat and charging is more efficent. So while 80% to 100% takes no less than 3.5 hours, the smaller single battery discharged an equal amount of amp hours as two batteries, will be in the more efficient faster charging range for longer.

Some get warm and fuzzies from lots of battery capacity, My warm and fuzzies come from lots of optimized ( adjustable voltage) charging sources. 200 watts of solar is nowhere near enough to satiate the demands of my AGM, but my alternator is 40+ at idle, upto 122, and I have a 40 amp plug in adjustable voltage power supply, and access to a 94 amp adjustable voltaeg power supply, and have hooked those in parallel for 134 amps into my 400$+ Northstar group 31 battery.

I also carry 2 small AGM portable batteries, one 18Ah and one 22AH. I guess I could wire one or the other to 'battery 1', but I keep them in my electrical cabinet next to a plethora of 45 amp anderson powerpoles that are inputs or outputs.

options are always good. having the ability to cycle one battery then flip a switch and then charge one battery while discharging the other is a good ability to have, but will it actually be beneficial? perhaps yes, perhaps not, and perhaps it just introduces too much human error factor which is basically when, not 'if'

if one does do this, have a highly visible voltmeter for each battery so one can see 14.7v on one and 10.2 on the other and curse themselves to an appropriate degree.

[rvpopeye]

I'm convinced SW's method of matching the battery capacity to the amount you actually use is probably the best way to go.

The tricky part is ,,,how much do you actually use ?
Is there such a thing as average ?

Ratio of sun to clouds .....so many variables ! OH my !

So , no system is ever going to be perfect all the time.
No two users are going to have the same needs.
Even the same user varies from day to day!
Getting it perfect the first try ? Possible ! but not very likely...

Bottom line.
Learning how it all works together , adding your own experience (and a bit of what others did) is your best approach to the design and successful use of a solar set up.

Everybody's mileage does vary on this. "No set rules...more like GUIDELINES!"
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Keep asking ???? as they pop up. We'll probably get you closer to it than a salesman .....it depends....