Do TIGOs actually work?

[Phil Timmons]

Talking about the "Rapid Shutdown" feature.

From what I follow -- these are supposed to Shut Down in the absence of a "stay alive" signal -- which is either "injected" into the DC lines or a wireless "CCA" module.

Kill the signal and they are supposed to shut down the DC in 30 seconds or less?

Been sort of testing more than a few . . . . killing the power to the CCA and signal generators . . . . and the DC just keeps going?

Anyone else seeing this? Thanks!

 

[jaggedben]

RS doesn't require voltage to go away completely, just be less than 30 volts (if the conductors leave the array) after the 30 secs. What voltage readings were you getting?

 

[Phil Timmons]

RS doesn't require voltage to go away completely, just be less than 30 volts (if the conductors leave the array) after the 30 secs. What voltage readings were you getting?

Full string voltage (obviously varies by string) . . . typically 250 to 350 VDC.

 

[ggunn]

Full string voltage (obviously varies by string) . . . typically 250 to 350 VDC.

Have you got more than one inverter and are you just turning off one of them? Tigo boxes on multi inverter PV systems sometimes have crosstalk issues. That's not how rapid shutdown is supposed to work, anyway; the code only says rapid shutdown is to be initiated by the disconnect designated to do so, which is usually the PV AC disco for the whole system.

 

[Phil Timmons]

Have you got more than one inverter and are you just turning off one of them? Tigo boxes on multi inverter PV systems sometimes have crosstalk issues. That's not how rapid shutdown is supposed to work, anyway; the code only says rapid shutdown is to be initiated by the disconnect designated to do so, which is usually the PV AC disco for the whole system.

No, I am seeing this with only ONE signal injector (or even NO CCA and NO Signal Injector). The TIGOs just come on and stay on. Shut off the inverters and everything . . . and the DC feed(s) just stay on. Strange part is there is one (older site, with signal injector) where the original part of the system is fully functional. That is over a year old. We added 10 TIGOs + panels -- and the new string does not shut down.

You follow (we both do, right?) that the initiation method does not matter -- when the "Stay Alive" signal goes away -- the TIGO is supposed to shut-down.

My ponderance is if they are picking up some sort of "Stay Alive" from elsewhere -- or just even (dys)functioning due to neighbor noise -- of if they have sent out a batch of bad RSD or what? Most of these are with the Optimizer feature, if that helps any other pondering?

 

[ggunn]

You follow (we both do, right?) that the initiation method does not matter -- when the "Stay Alive" signal goes away -- the TIGO is supposed to shut-down.

My ponderance is if they are picking up some sort of "Stay Alive" from elsewhere -- or just even (dys)functioning due to neighbor noise -- of if they have sent out a batch of bad RSD or what? Most of these are with the Optimizer feature, if that helps any other pondering?

It only matters if you are trying to initiate rapid shutdown by any other method than by opening the PV AC disco or whatever is the one switch that is designed to do it. In a system I designed with (10) SunSpec compliant inverters the inspector failed us because turning off one inverter breaker did not shut down all the DC to that inverter because the keep alive signal was being picked up via crosstalk from the DC conductors from other inverters that were still running. That was despite our referring him to the NEC articles that describe how rapid shutdown is supposed to work, and this wasn't it; if we shut down the whole system all the RS devices shut down the DC, just like they are supposed to.

Insert rant about inspectors writing code in the field.

 

[ggunn]

No, I am seeing this with only ONE signal injector (or even NO CCA and NO Signal Injector). The TIGOs just come on and stay on. Shut off the inverters and everything . . . and the DC feed(s) just stay on. Strange part is there is one (older site, with signal injector) where the original part of the system is fully functional. That is over a year old. We added 10 TIGOs + panels -- and the new string does not shut down.

You follow (we both do, right?) that the initiation method does not matter -- when the "Stay Alive" signal goes away -- the TIGO is supposed to shut-down.

My ponderance is if they are picking up some sort of "Stay Alive" from elsewhere -- or just even (dys)functioning due to neighbor noise -- of if they have sent out a batch of bad RSD or what? Most of these are with the Optimizer feature, if that helps any other pondering?

Were the DC modules still connected or was there DC voltage trapped on the conductors? That charge has to be bled off somehow. The original SolarEdge inverters used to require a high value resistor across the DC terminals to be RSD compliant.

 

[Phil Timmons]

Were the DC modules still connected or was there DC voltage trapped on the conductors? That charge has to be bled off somehow. The original SolarEdge inverters used to require a high value resistor across the DC terminals to be RSD compliant.

That is possible. Thanks. Will try that.

If that is the case any ponders on why the older TIGOs seem to work?

The older TIGOs drop down to 1 volt each, so you can add up to how many are in the string.

Answer that came back from the sales/supplier was that they are only required to be installed -- not actually work. ;P

 

[jaggedben]

Answer that came back from the sales/supplier was that they are only required to be installed -- not actually work. ;P

I suppose if inspectors don't ask for a demonstration then practically speaking people can get away with that. But if there's ever a lawsuit, delete that email so it's not part of discovery.

 

[Phil Timmons]

Were the DC modules still connected or was there DC voltage trapped on the conductors? That charge has to be bled off somehow. The original SolarEdge inverters used to require a high value resistor across the DC terminals to be RSD compliant.

More detailed answer -- connected to inputs on Sol-Ark Inverters. Seemed to make no difference if the Inverters were On or Off.

 

[ggunn]

More detailed answer -- connected to inputs on Sol-Ark Inverters. Seemed to make no difference if the Inverters were On or Off.

I am not that familiar with Sol-Ark inverters, but I know that there are some Tigo boxes that are not compatible with some inverters. Do both Sol-Ark and Tigo say that the combination you have is a compatible pair? I assume that since you have multiple inverters you have a single handle that isolates them all from the grid; what happens when you open that switch? Do you also have battery integration? If so, is it the Sol-Ark inverters that power the microgrid in island (off grid) mode?

 

[Phil Timmons]

I am not that familiar with Sol-Ark inverters, but I know that there are some Tigo boxes that are not compatible with some inverters. Do both Sol-Ark and Tigo say that the combination you have is a compatible pair? I assume that since you have multiple inverters you have a single handle that isolates them all from the grid; what happens when you open that switch? Do you also have battery integration? If so, is it the Sol-Ark inverters that power the microgrid in island (off grid) mode?

Yes, Sol-Ark specificially recommends TIGO. Because . . . well who else are they going to call? Solar-Edge?

As far as not having dealt with Sol-Ark . . . I am sort of wanting to stay "loyal" to them -- they are local . . . but they are just about goofy to the max. They have tried to make a "swiss army knife" device -- DC to AC inverter, grid-tie, battery charger/regulator, generator tie-in, RSD init, software-based-load-management, and (I am sure someone can add something else) all in one-box . . . and claim that box is EMP resistant for a few dollars more (yeah, for the End-Timers) . . . and sell it all at premium, with HYPE settings all turned up to 11.

The presentation is that is a USA #1! thing, but from what I follow it is really a Ningbo Deye Inverter, repackaged and marked up for retail, made in China, while Lion is 100% doing a terminal-for-terminal match copy-and-paste rip-off with an even worse user interface.

I suppose it is obvious that I am not too impressed -- but the basic hardware seems to function, so there is that.

In some cases we have seen the TIGO dysfunction with Single Inverters, in some cases with Multiple Inverters -- but this non-RDS Fail occurs without regard to the inverters, per se. We are talking about the ABSENCE of the Stay Alive portion -- a TIGO part of the product. Maybe think of an E-STOP. E-STOP kills the primary, and everything drops (please, please no one -- no compulsory 10 page essays on E-STOP theory and practice).

But yes, the Sol-Arks do On Grid, Off-Grid, Optimized Feed (Splits battery feed and grid feed), Battery-only-UPS, Generator Transfer Switch . . . on and on and anything else anyone could think of. Even the docs are screwy. My kid has offered to proof-read their manual for them just to get the spelling and grammar correct.

 

[Phil Timmons]

delete

 

[tortuga]

Anyone else seeing this? Thanks!

Yes I have had two similar experiences. Both times I was sent to replace a faulty inverter, shut off the inverter, killed the AC and hit the rapid shutdown to de-energize the DC side and it stayed on ~480 volts DC. I figured it was some capacitance in the line and reported it to the solar contractor. The really annoying thing was since I did not trust the rapid shutdown but wanted to be sure the DC was off I had to lift a solar panel off the roof to disconnect the DC.

 

[pv_n00b]

Yes I have had two similar experiences. Both times I was sent to replace a faulty inverter, shut off the inverter, killed the AC and hit the rapid shutdown to de-energize the DC side and it stayed on ~480 volts DC. I figured it was some capacitance in the line and reported it to the solar contractor. The really annoying thing was since I did not trust the rapid shutdown but wanted to be sure the DC was off I had to lift a solar panel off the roof to disconnect the DC.

I would caution everyone not to depend on RSD as a tool for isolating the voltage in the array for the purpose of performing maintenance. It's not intended for or designed for use as a safe shutdown for maintenance tool.

 

[pv_n00b]

Talking about the "Rapid Shutdown" feature.

From what I follow -- these are supposed to Shut Down in the absence of a "stay alive" signal -- which is either "injected" into the DC lines or a wireless "CCA" module.

Kill the signal and they are supposed to shut down the DC in 30 seconds or less?

Been sort of testing more than a few . . . . killing the power to the CCA and signal generators . . . . and the DC just keeps going?

Anyone else seeing this? Thanks!

Maybe you got a batch of TS4-A-Ms by mistake? It's the only one they have without RSD built in.

 

[ggunn]

I would caution everyone not to depend on RSD as a tool for isolating the voltage in the array for the purpose of performing maintenance. It's not intended for or designed for use as a safe shutdown for maintenance tool.

Yeah, well, try telling that to an inspector who insists otherwise, that turning off a single inverter for maintenance in a multi inverter system must activate all the DC connected to that inverter even though there is nothing in the NEC to support his position.

 

[tortuga]

I would caution everyone not to depend on RSD as a tool for isolating the voltage in the array for the purpose of performing maintenance. It's not intended for or designed for use as a safe shutdown for maintenance tool.

Wow really but then how is it safe for fire fighters whom might be about to chainsaw thru the same wires?

 

[ggunn]

Wow really but then how is it safe for fire fighters whom might be about to chainsaw thru the same wires?

If they initiate RSD the way they are supposed to, which is by engaging the designated RSD initiator switch (usually the AC disconnect for the PV system), then there should be no DC voltage on the conductors and it will be safe for them. If they try to initiate RSD any other way (like opening an inverter breaker or DC disconnect, for example), then maybe not so much.

 

[jaggedben]

If they initiate RSD the way they are supposed to, which is by engaging the designated RSD initiator switch (usually the AC disconnect for the PV system), then there should be no DC voltage on the conductors and it will be safe for them. If they try to initiate RSD any other way (like opening an inverter breaker or DC disconnect, for example), then maybe not so much.

There may still be plenty of DC voltage on the conductors as discussed here.

I think what pv_noob is saying is that what is considered safe for firefighters to interact with a solar array and what is safe for someone doing maintenance and troubleshooting are not the same thing.