I am considering adding a The One inverter and 1-2 MNPowerFlo16 batteries to my house. The inverter needs to be in my mechanical room due to the connections to the panels, generator, AC couple PV, and potential future DC coupled PV. Recent battery incidents in the news, however, make me question putting the batteries in there as well (plus it is getting a bit full, and not build from inflammable materials). I could have a concrete shed built outside the mechanical room, however. The total run distance from inverter terminals to battery terminals would likely be 20-24'. That's quite a distance for 50vdc to go. Is this doable? What gauge cables would be required/recommended?
You can put your numbers into a voltage drop calculator .
This is the one I like to use .
https://www.southwire.com/calculator-vdrop
I don't know if I used the correct numbers from your system - you probably want the lowest voltage your batteries would ever be at. And also account for surge amps of induction loads on the inverter . Also plan on expansion in future of more batteries.
1 conductor per phase utilizing a 3/0 AWG copper conductor installed Cable, Conduit (non-Steel), & Direct Burial will limit the voltage drop to 1.39% or less when supplying 200 amps for 25 feet on a 50 volt single phase system.
Larry
Thanks, I tried their calculator. It's a bit surprising the variance between different online calculators. This one is by a wiring supplier though, so that's promising.
This morning I broke out a tape measure and I think the distance can be more like 5m / 16'. This battery's listed operating voltage is 46.4v minimum (thanks for that, I had just been using the nominal voltage). The result is AWG4/0 with sub-1% drop. And that's in conduit. So I think this is doable, and safer than indoors or against the house siding.
Nice thing is the Southwire calculator you can select DC for it - though doesn't usually make too much difference compared to AC from what I have seen.
Larry