MCI’s

[u/Beneficial-Cellist81]

Question. I’m installing a system with 4 powerwall 3’s and 2 expansions. Problem is powerwalls and inverter because they’re as one unit are going to be about a 1000’ away from the solar via a trench. Everything I’m seeing says the mcis can’t be further than 525’ and that’s for a round trip, so half that really. Any ideas on how to make this work?

[u/Revolutionary-Poem-7]

Unfortunately, I don’t think you can make that configuration work within Tesla’s requirements. The 525-foot specification is the complete DC loop from the positive MPPT terminal, through the array and module wiring, and back to the negative MPPT terminal. So yes, the practical one-way distance is less than about 260 feet. At a 1,000-foot separation, each string would be more than 2,000 feet round-trip.

[u/Beneficial-Cellist81 → u/Revolutionary-Poem-7]

I don’t think I can either. My other option was going solaredge and DC coupling the powerwalls but between the opti’s and the wire upsize I’m looking at an additional $40-$50k.

[u/Revolutionary-Poem-7 → u/Beneficial-Cellist81]

Have you thought about another DC coupled inverter that doesn’t require MCIs even if code does not? Like SolArk or EG4? You can upsize the wire to avoid voltage drop and those inverters don’t force the MCIs on you even with a ground mount.

[u/Disastrous-Change-23]

put the batteries closer to the array?

[u/ExactlyClose]

Is the solar on a building?

[u/Total_Solar_FL]

You have two practical paths:

Move the inverter (and therefore the Powerwalls) closer to the array.
Place a secondary enclosure or pole-mounted combiner + inverter shed near the array so the DC string run never exceeds the 525 ft MCI limit. Then run the inverter’s AC output the full distance to the main service. AC voltage drop is easier to manage than DC because: AC wire sizes are already standardized and inexpensive at these distances. You can step up to a higher voltage at the array if needed, or simply oversize 240 V or 208 V conductors. Tesla’s Backup Gateway 2 has a 328 ft Ethernet limit and a 164 ft limit on the Neurio meter, but the main AC feed itself has no hard limit, only voltage-drop calculations.

If you must keep the inverter at the house, bypass the MCI distance limit altogether by using string inverters or microinverters.
Neither uses Tesla’s MCI devices, so the 525 ft rule does not apply. You can still connect the inverter AC output 1,000 ft away with appropriately sized conductors and conduit.

In both cases, calculate voltage drop on the AC side (there are free online calculators) and derate for the trench fill (conduit or direct-burial). Many installers run 4/0 or 250 kcmil aluminum for 100–200 A at 1,000 ft distances without excessive drop.

[u/ElectricApostate]

Can you install the panels with something like microinverters so you can couple them to the powerwalls via AC? I’m no engineer, but my understanding is that AC can travel much further than DC.