My first thread probably should have been my second. So I'm making my second my first.
After reading suggestions here & elsewhere, I'm considering revamping my planned 12V system in favor of 24. But no matter what angle I view the change from, it seems to only make things much more difficult. I don't want to be 'that guy' who ignores good advice, but I'd really like to understand the 'why' behind the advice to go 24 over 1000W, particularly as it pertains to my original plan and my particular use-case (RV 'from scratch' conversion with lots of 12V needs).
What I had originally envisioned was:
6 x 1200AH, 2V AGM batteries (single string in series)
Magnum MS2012 12V 2000W inverter / charger
4 x 300W, 36V panels (2 on each controller, each pair paralleled to minimize shading issues)
2 x 50W MPPT controllers
4/0 battery interconnects, 4/0 cabling from bank to inverter (5' max), 250A DC breaker between the two, plus a 300A fallback fuse.
2 parallel-capable 2000-ish watt generators (for cloudy-day charging, power tools, short-term AC use, etc)
An upgraded alternator + battery isolator to provide a third battery-bank charging source.
In order to meet my storage requirement w/ 24 volt, I'd end up using 8 x 400AH 6V batteries (2 strings of 4 each), and while I'd then only need one controller, the 2 extra batteries cost way more than the savings of a single controller (and weigh ~200lbs more, which is a major consideration for me). With 24V, I'd be using #1 AWG vs #4/0 (neither of which I could terminate myself anyway), and while there would be some cost diff, it still wouldn't be enough to make up for the extra battery cost. Same with the DC breaker/fusing. 24V w/ 8 batteries is still more costly than 12V w/ 6. And then there's the cost (in money & efficiency) of a 24/12 converter, and/or hard(er) to find 24V lighting/appliances. I'm just not seeing 24V being more economical. For me, it's less.
95% of the time, I will not be drawing anywhere close to 2000W. The peak load with pretty much everything I've planned on running, all operating at once, is 80A. The microwave is the one thing I designed for that would temporarily push this system from 1000W to 2000 territory. And we won't be using that much if at all.
So...
Assuming I use only quality cabling built by businesses with the proper equipment to do so (not me), and I have an electrician either build and/or inspect my load center / wiring (which I would also inspect on a regular basis), and I keep my wire runs code-compliant (more than code compliant, actually), can my case be an exception to the rule? If so, what should I do to make my 12V system as safe as a comparable 24V equivalent. And if not - why not?
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