SolarCity H6 startup issue

[Rdz2001]

My friend and I just wrapped up the installation of a 12kW array feeding two SolarCity H6 inverters. We were following the startup procedure when the utility guy noticed something odd. With no AC supplied to the inverters and the AC disconnect open, we were seeing about 30VDC on the AC line per inverter right after closing the DC disconnects. This voltage slowly bled down to zero over about a minute after we opened the DC disconnects again. Both inverters behaved identically and otherwise seemed to boot up fine once the DC was connected. He said he wouldn't energize the system until we can explain this so we're a bit stuck. Any insights?

 

[RobtheGreat]

Yeah, what you're seeing is likely just backfeed from the inverter's output filter caps through the output relay contacts or leakage paths even with the relays open, there's sometimes a small amount of stray capacitance or bleed through that can show up as low voltage on the AC side but not to fret, t's not true power, just a harmless residual voltage that slowly discharges when the DC input is cut

 

[EastLand66]

That's just the inverter's AC filter caps holding a tiny DC charge. totally normal. A quick bleeder like a small resistor or lamp across L1/L2 dumps it instantly and keeps the utility happy.

 

[eevee]

@EastLand66 That lamp trick is for real. I've used a 100W bulb before and it drains the charge real quick without messing with anything else. Anyway, @RobtheGreat I appreciate the breakdown, man. Helpful for those just starting here.