Growatt SPF 5000 ES-US AC Voltage on PV input

[i8iridium]

I purchased a refurbished Growatt SPF 5000 ES-US (their description) from Signature Solar. First off, I’m having a hard time determining if this unit is actually the US model. From my reading on here and watching YouTube, I think it’s not. I checked for continuity between ground and N, and I’m getting zero ohms. Nothing is connected to the inverter when I checked for continuity.

Secondly, and most importantly, I was checking voltages with an inverter generator supplying 240v AC to the GroWatt, and I measured over 100vAC between the case and the PV input. That seems odd and dangerous to me.

Can some tell me if I’m crazy or is this to be expected?

 

[timselectric]

Can some tell me if I’m crazy or is this to be expected?

To be expected.

And I can't imagine why Signature Solar would even have a non US version. But, it's just a simple screw removal, to convert it.

 

[i8iridium]

To be expected.

And I can't imagine why Signature Solar would even have a non US version. But, it's just a simple screw removal, to convert it.

Interesting.

I've read in-depth about the screw, but Ideally I'd like the product that I ordered. Already contacted signature solar to find out next steps.

 

[timselectric]

Interesting.

I've read in-depth about the screw, but Ideally I'd like the product that I ordered. Already contacted signature solar to find out next steps.

All of the ones that Signature Solar sell. Come from the factory without the screw or relay.
But since this one is refurbished. Maybe someone returned an EU version. And it slipped through.

 

[i8iridium]

All of the ones that Signature Solar sell. Come from the factory without the screw or relay.
But since this one is refurbished. Maybe someone returned an EU version. And it slipped through.

Do you know of any inverters that don't pass through the AC voltage? MPP LVX6048?

 

[timselectric]

Do you know of any inverters that don't pass through the AC voltage? MPP LVX6048?

Haven't looked into it. But maybe the really expensive ones.
It's not a big deal. You shouldn't be working on this stuff live, anyway.

 

[i8iridium]

I forgot about following up on this, but I just wanted to close it it out. Turns out the referb unit I bought from Signature Solar ended up actually having an issue. Whether it was actually an EU model or not, we will never know. After some back and forth, with support they ended up shipping me a new SPF 5000 ES-US. There's no labeling on it that says it's a US model, but it doesn't have continuity between ground an N like the referb did.

All that being said, I ended up purchasing a EG4 6000XP which works MUCH better for my project. Anyone looking for GroWatt SPF 5000 ES-US? @timselectric?

 

[timselectric]

I'm always looking for a great deal for spare equipment.

 

[RCinFLA]

Many inverters have a relay that connects neutral to case ground on inverter when there is no AC input. This represents off-grid configuration.

When AC input is applied the relay releases the neutral to case ground connection, turning over responsibility for neutral-ground bonding to AC input path connections. This represents on-grid configuration with single point neutral-ground bonding within the main grid breaker panel.

Most low cost HF AIO inverters do not provide isolation for the inverter's HV DC bus and PV inputs. The AC output PWM sinewave synthesizing H-bridge flips the HV DC (about 250vdc for 120vac output) polarity of HV DC bus relative to neutral connection on H-bridge to generate positive and negative going AC sinewave output. Since the PV SCC controller goes directly to HV DC bus without isolation it goes along for the ride with H-bridge polarity switching. Both positive and negative PV lines will be riding on top of this HV DC polarity switching and is why you need to use double pole DC PV breakers to panels.

This non-isolated PV input arrangement come from the transformerless grid-tie inverters design.

HF AIO inverters like SolArk and Deye with split-phase 240/120vac output have an intermediate DC to DC converter between PV SCC controller and HV DC bus of inverter that provides galvanic isolation between AC output lines and PV inputs.