Signature Solar EG4 6.5K Off-Grid Inverter | 6500EX-48

[EJansen]

This is a beautiful setup - would you mind if I stole this picture?

Feel Free.

 

[ncsolarelectric]

...
I'll add it to my test list. Unfortunately, I won't be able to look into it for a couple of weeks.

Regarding this issue for Rapid Shutdown Devices. The RSD must disconnect the PV wires at both ends. You need a set of DC contactors at the inverters AND the TIGOs on the roof. SolarBOS makes contactor boxes with PV disconnect switches that you could use as your outdoor accessible RS switch. The EG4 inverter does not have an internal PV Contactor, so the wires are back-fed by the capacitors inside the inverter, which take too long to discharge to meet the RS code. The combiner box below is how it's done. You can get any number of contactors. You could forgo the TIGO modules and just add one of these on both ends of the PV wires.

 

[EJansen]

Regarding this issue for Rapid Shutdown Devices. The RSD must disconnect the PV wires at both ends. You need a set of DC contactors at the inverters AND the TIGOs on the roof. SolarBOS makes contactor boxes with PV disconnect switches that you could use as your outdoor accessible RS switch. The EG4 inverter does not have an internal PV Contactor, so the wires are back-fed by the capacitors inside the inverter, which take too long to discharge to meet the RS code. The combiner box below is how it's done. You can get any number of contactors. You could forgo the TIGO modules and just add one of these on both ends of the PV wires.

View attachment 103048

Awesome, thanks for the support! I shot them an email to get a quote / see what options they have for me. Appreciate you guys.

 

[Zwy]

Fortunately (ok unfortunately - I was waiting for a few more rail clamps), I still have two more panels to install, so I need to go back up on the roof anyhow, so I can do more testing.

The more complete the testing, the more data and complete picture you get.

The separator that I put in there is metal - just don't know if it would pass an inspection. What would you suggest changing it to?

It's a little large on spacing to be a faraday cage.

Solid metal would be preferred, you are looking at splitting the trough into separated AC and DC circuits run in separate raceways inside the trough to minimize induced current.

As far as the trough being grounded, if the sub panel is grounded, and it's connected to the trough via metal conduit, would that suffice, or would an inspector be looking for a specific ground wire?

Might depend on state electrical code. I will say raintight connections I would run an EGC.

Read more here: https://forums.mikeholt.com/threads/using-metal-conduit-as-egc.140494/

Some states require it for seismic activity or other reasons. Opinions on the matter are certainly a hot topic in that thread.

I know I have a few things left to do before I'd get it inspected, so any feedback on anything you guys see, is appreciated.


There's no neutral / ground bond in the Sub panel. I have the screw, it's just not in use.

I'm referring to the main panel.

I actually did neutral bus bar to grounding bus bar and neutral bus bar to grounding electrode as well - they all had the same 5.7 - 5.8v AC fluctuating range.

Grounding electrode from neutral bus bar, was it actually the electrode or the wire? The electrode should be earthed, 0V.

If the system has proper bonding, it should be 0V.

I'll add it to my test list. Unfortunately, I won't be able to look into it for a couple of weeks.

Keep us updated on results.

 

[EJansen]

SolarBOS makes contactor boxes with PV disconnect switches that you could use as your outdoor accessible RS switch.

This is the response that I got from them when wanting to purchase:

"I’m sorry this is not something we can help you with as we only sell to companies for projects."

That's pretty unfortunate... Know of another option that'll allow 'non-company' entities to purchase from them?

 

[EJansen]

The more complete the testing, the more data and complete picture you get.




It's a little large on spacing to be a faraday cage.

Solid metal would be preferred, you are looking at splitting the trough into separated AC and DC circuits run in separate raceways inside the trough to minimize induced current.

Thanks, I'll research it a bit more and see what I can find.

Might depend on state electrical code. I will say raintight connections I would run an EGC.

Read more here: https://forums.mikeholt.com/threads/using-metal-conduit-as-egc.140494/

Some states require it for seismic activity or other reasons. Opinions on the matter are certainly a hot topic in that thread.

5 minutes of work - easier to just make it happen, so I'll knock that out when I get back.

I'm referring to the main panel.

Ah, ok, yeah, the main panel is bonded.

Grounding electrode from neutral bus bar, was it actually the electrode or the wire? The electrode should be earthed, 0V.

If the system has proper bonding, it should be 0V.


Keep us updated on results.

Will do! Thanks again!

 

[ncsolarelectric]

This is the response that I got from them when wanting to purchase:

"I’m sorry this is not something we can help you with as we only sell to companies for projects."

That's pretty unfortunate... Know of another option that'll allow 'non-company' entities to purchase from them?

They didn't even direct you to their distributors? Sad. CED Greentech is a distributor. If you can't find SolarBOS through distributors, I've got a company, I can buy and resell them to you. DC contractors that are UL listed for this purpose are out there by various manufacturers, not just SolarBOS.

 

[EJansen]

They didn't even direct you to their distributors? Sad. CED Greentech is a distributor. If you can't find SolarBOS through distributors, I've got a company, I can buy and resell them to you. DC contractors that are UL listed for this purpose are out there by various manufacturers, not just SolarBOS.

OK, I'll talk to those guys. I also found this and it appears that it would work. Figured I'd just find something with a 24v coil so that I can control the TIGOs and whatever contactor option that I find.

Shopping

www.factorymation.com

Thats pretty pricey @ $360 per contactor (good for only 1 string) at least in my limited experience with them.

 

[ncsolarelectric]

OK, I'll talk to those guys. I also found this and it appears that it would work. Figured I'd just find something with a 24v coil so that I can control the TIGOs and whatever contactor option that I find.

Shopping

www.factorymation.com

Thats pretty pricey for a contactor at least in my limited experience with them.

Honestly, it's probably cheap compared to the whole combiner box, but I agree. Anything to do with RSD is pricey IMO.

 

[EJansen]

Honestly, it's probably cheap compared to the whole combiner box, but I agree. Anything to do with RSD is pricey IMO.

It wouldn't be so bad if it was for multiple strings, but damn - that guy is $360 for disconnecting just one string.

 

[koppted]

This is the response that I got from them when wanting to purchase:

"I’m sorry this is not something we can help you with as we only sell to companies for projects."

That's pretty unfortunate... Know of another option that'll allow 'non-company' entities to purchase from them?

I contacted them earlier this year about an AC combiner box that they made, and that is the same response I got. I ended creating one myself. I expect or maybe hope they're are out of business soon. I know you're not supposed to wish evil on others, but "thems the breaks."

 

[Subdood]

A question for y'all and especially @RichardFromEG4. Each of the PV inputs on this inverter have a Voc limit of 500V, and operating voltage of 90-450V. Say I have 9 bifacial panels with a Voc of 50V. That makes a total of 450Voc. Say it's a cold sunny day at about 32F. With a panel Voc Tc of -0.25%/C this would push the Voc of each panel up to about 53.1V and 478V for the entire string. This is still below the 500Voc limit. But, when these panels get a little bit of light, they're going to be pulling a little bit of current, albeit in the tenths of amps range. So, at this point they'd be considered 'operating', but they may still be above the operating limit of 450V, until they get more sun and draw more current, and the panel voltage drops toward Vmp, in this example of 41V.

So the question is, would this scenario damage the PV input, that is, operating above 450V, but below 500V?

Another hypothetical. The PV input power limit is 4kW, and current limit is 18A. What if I have some bifacials rated at 450W, with a Vmp of 41V, and I have 8 of them in series on one input. Max power for 8 would be about 3.6kW, and the Vmp is about 328V for the string. Current at this point is about 11A. What happens when like in the above situation, with snow on the ground and a sunny day at 32F, these bifacials pull another 25% more power because of light reflecting back onto the back of the panels? 25% more power per panel comes out to about 563W. The current rises to about 13.8A.

So now we have 4.5kW on this string (563W x 8), but the current is around 14A. Since the Vmp doesn't increase, we are sitting at a string voltage of 328V. So, we're not exceeding the operating voltage or current limits of the input, but are above the 4kW limit. What happens here? Does the input clip this when the power exceeds 4kW?

Thanks.

 

[Solar Guy Richard]

A question for y'all and especially @RichardFromEG4. Each of the PV inputs on this inverter have a Voc limit of 500V, and operating voltage of 90-450V. Say I have 9 bifacial panels with a Voc of 50V. That makes a total of 450Voc. Say it's a cold sunny day at about 32F. With a panel Voc Tc of -0.25%/C this would push the Voc of each panel up to about 53.1V and 478V for the entire string. This is still below the 500Voc limit. But, when these panels get a little bit of light, they're going to be pulling a little bit of current, albeit in the tenths of amps range. So, at this point they'd be considered 'operating', but they may still be above the operating limit of 450V, until they get more sun and draw more current, and the panel voltage drops toward Vmp, in this example of 41V.

So the question is, would this scenario damage the PV input, that is, operating above 450V, but below 500V?

Another hypothetical. The PV input power limit is 4kW, and current limit is 18A. What if I have some bifacials rated at 450W, with a Vmp of 41V, and I have 8 of them in series on one input. Max power for 8 would be about 3.6kW, and the Vmp is about 328V for the string. Current at this point is about 11A. What happens when like in the above situation, with snow on the ground, these bifacials pull another 25% more power because of light reflecting back onto the back of the panels? 25% more power per panel comes out to about 563W. The current rises to about 13.8A.

So now we have 4.5kW on this string (563W x 8), but the current is around 14A. Since the Vmp doesn't increase, we are sitting at a string voltage of 328V. So, we're not exceeding the operating voltage or current limits of the input, but are above the 4kW limit. What happens here? Does the input clip this when the power exceeds 4kW.

Thanks.

It should not damage the operation of the unit. It would likely disable production but that's the point of an operating limit that is lower than the max VOC - to protect the unit. Regarding your second question, yes it will clip your power - but most people overamp and over watt their solar array because you will rarely see 100% of your rated power output, so people do it on purpose. Just never exceed the VOC limit.

 

[Subdood]

It should not damage the operation of the unit. It would likely disable production but that's the point of an operating limit that is lower than the max VOC - to protect the unit. Regarding your second question, yes it will clip your power - but most people overamp and over watt their solar array because you will rarely see 100% of your rated power output, so people do it on purpose. Just never exceed the VOC limit.

Ok thanks. So you're saying if it's running in that range of 450-500V, it may not run at all in this range, until it drops below 450V?

Regarding overamping the input, how much above the 18A limit is considered acceptable before you risk damaging it?

I've noticed on the website that the availability of this inverter went from late July to mid September. And the price dropped $50. Plus, the Lifepower4 48V batteries weren't supposed to be until August but are available now. What happened in these cases?

 

[Chaunbot]

Ok thanks. So you're saying if it's running in that range of 450-500V, it may not run at all in this range, until it drops below 450V?

Regarding overamping the input, how much above the 18A limit is considered acceptable before you risk damaging it?

I've noticed on the website that the availability of this inverter went from late July to mid September. And the price dropped $50. Plus, the Lifepower4 48V batteries weren't supposed to be until August but are available now. What happened in these cases?

Maybe the fault 61 issues are hardware level and they have to fix before it leaves china. Just a guess

 

[Subdood]

Maybe, but I'd like to know the other answers as well.

 

[Solar Guy Richard]

Regarding overamping the input, how much above the 18A limit is considered acceptable before you risk damaging it?

I don't know that I can give an official response on this for a lot of reasons. Best thing I can say is to do research on how amperage (and overamping for solar specifically) works.

I've noticed on the website that the availability of this inverter went from late July to mid September. And the price dropped $50. Plus, the Lifepower4 48V batteries weren't supposed to be until August but are available now. What happened in these cases?

In general, shipping right now is a complete mess. We do our best constantly to give accurate timeframes, but there are so many things that happen to slow down or speed up our expectations that until we have it on a truck driving to our warehouse, we can't really be 100% sure of anything other than using our previous experience to try and get the timing right. As far as the $50 credit, Signature Solar and us felt it was appropriate given we are asking for you to prepay and wait for weeks or months for the product to arrive. It's basically a thank you.

 

[EJansen]

@RichardFromEG4 - Do you know if there's any way to remotely shut down the inverters for a Rapid Shutdown type scenario?

 

[ncsolarelectric]

@RichardFromEG4 - Do you know if there's any way to remotely shut down the inverters for a Rapid Shutdown type scenario?

Thank you for asking. I'm curious to know too. I just found out that Sol-Ark has this feature, either contactor, relay, or breaker trip, to provide rapid shutdown at the inverter end of the wires, and the Tigo TS4's to disconnect at the panel end of the wires.

If the EG4 Inverter doesn't have a contactor, how long does it take for the PV input to discharge when shut down? Thanks!

 

[Solar Guy Richard]

@RichardFromEG4 - Do you know if there's any way to remotely shut down the inverters for a Rapid Shutdown type scenario?

I do not believe that function is built into this iteration. We may add features as we continue to develop these units.