Question re old batteries

[Sunking]

I feel like a fool for asking but here goes: How do I calculate how much amp-hour capacity my battery bank has?

I have four 150 amp-hour 6V batteries connect 2s, 2p for a 12V output. (yes, I know 24v is preferred, just need to order my 24V inverter)

I thought I had 4 x 150 = 600 amp-hours but I've convinced myself it is only half of that. When I do the c/12 c/8 calculations they make no sense.

In series AH remains the same, in parallel they add so you have two parallel strings so that is 300 AH

[br2an]

In series AH remains the same, in parallel they add so you have two parallel strings so that is 300 AH

Thanks again, Sunking.

That's good news and bad news for me. I thought I had 600 AH but actually only have 300 (bad news). The good news is that I have almost exactly the right amount of charge current (panels size: 380 Watt/12V = 31.7A, MPPT controller in use). Therefore 300 AH / 31.7A = 9.5 charge rate (or C/9.5) Please feel free to correct this if I'm wrong.

note: It occurred to me this evening that if 15A was sufficient to charge a single 150 AH 6V battery, then two of the same batteries in series would still only need 15A, just the voltage would double. Hence I realized I was either calculating my total AH wrong or applying the C/12 rate incorrectly.

Final question: why would two 150 AH 6V batteries be preferred over a single 12V 150 AH battery? Or is that just something that I have made myself believe because I was miscalculating the AH totals?

[Naptown]

Thanks again, Sunking.

That's good news and bad news for me. I thought I had 600 AH but actually only have 300 (bad news). The good news is that I have almost exactly the right amount of charge current (panels size: 380 Watt/12V = 31.7A, MPPT controller in use). Therefore 300 AH / 31.7A = 9.5 charge rate (or C/9.5) Please feel free to correct this if I'm wrong.

note: It occurred to me this evening that if 15A was sufficient to charge a single 150 AH 6V battery, then two of the same batteries in series would still only need 15A, just the voltage would double. Hence I realized I was either calculating my total AH wrong or applying the C/12 rate incorrectly.

Final question: why would two 150 AH 6V batteries be preferred over a single 12V 150 AH battery? Or is that just something that I have made myself believe because I was miscalculating the AH totals?

They are equal
Because it takes one string of batteries to get to the voltage.
Now 3 parallrl 12v 50 ah batteries are a problem.