Hub blowing out

mevenable

I have been working hard to figure out why the local installation company keeps messing up my hub.  They blew out 2 of them in late January trying to install the Flexmate cable, and finally gave up on that. Then in late March they brought in the final string of batteries, and messed up the Hub again.  Basically, it is working at the beginning of the operation, and when they go to turn everything back on it is unresponsive - no lights, no connection to the mate3, which is dark.  When the inverter is connected directly to the mate3, then the mate3 works fine, but there is no longer any information from the Charge Controller.  One thing that occurs to me is that it might be damaged by the huge spark that cracks like a rifle shot every time they have to hook the cable from the inverter back up to the batteries. The local company says this is all normal and harmless, that it is due to capacitance in the inverter.  Researching, it looks like normally there is a circuit breaker between the batteries and the inverter (and also between the batteries and the charge controller).  If such a breaker were present, and was off when they were connecting the cables, I suspect that there would not be a spark.  Question is whether this is what is damaging the Hub.  I am going to try to attach a photo of my system (minus the hub, which I am hoping they will replace once again on Monday). From left to right, the circuit breaker box, the circuit breaker from the PVs, the charge controller, the circuit breaker box for the grid, the inverter, and the mate3s.  the  If anyone sees anything else that sends up a red flag, let me know.  These guys do not seem to quite know everything, and I certainly don't

Estragon

All breakers between devices and battery bank should be open (off) when making final battery connections so there is no load across the connection. The breaker for pv to controller should also be opened. When the battery connection is completed, close the battery to device breakers, wait for the devices to boot up fully, and then close the pv breaker.

Whether not doing this, or doing it in the wrong order is causing the hub issue, I don't know. It's a possibility though. That it happens when the hub is connected to the controller seems suggestive to me. Maybe the inverter is okay with handling the sparkiness, but the controller may not be, and could get wierd if rebooting from pv voltage alone. In any case, it's just plain wrong to make sparky connections when it can be easily avoided by opening the breakers.

mcgivor

 Overcurrent protection is not merely a convenience, a short circuit would allow the batteries to push thousands of amps there should be protection on both the battery to inverter and controller to battery because both are connected directly to this high potential current. 

Raj174

@mevenable
I do not see the two 175 amp breakers for the Radian inverter. Are they installed? This is a GS8048A right? It has two 4000 watt power modules with battery connections on the bottom of the inverter, each requiring a minimum 2/0 AWG pos and neg cables (4 cables) with 175 amp breakers. Each module needs it's own breaker. Did they not recommend using the GSLC panel made for this inverter? It would have made life and installation much easier.

Rick

Estragon

I don't see breakers (or fuses) for the charge controller either. Hopefully, they're there someplace but just can't see in the pic.

If there aren't breakers (or less ideally fuses), I highly recommend getting someone who knows what they're doing to check over the entire system. As McGivor and Rick note, such a lack of protection is dangerous, and you're lucky to get away with just frying a hub. If your "local installers" actually installed without OCP on the battery connections, they clearly don't know what they're doing (or perhaps worse, don't care and just want to make a few extra bucks on the job).

mevenable

Exactly  These guys do represent outback here in country, and have training seminars with them, but they did NOT as far as I can see put in any sort of circuit breakers between the CC and the batteries, and the inverter and the batteries.  Oddly, an Outback trainer came to our farm during a training exercise and saw the setup, and did not say anything about the circuit breakers.  He also did not comment on the fact the batteries were (at that time) jammed up against each other and the temperature sensor sitting on top.  I figured that one out by reading and got it adjusted.  Apparently it is like so many things, standards of first world companies go downhill in the third world. 

mevenable

btw, when they re-connect the cables to the battery bank, the inverter and CC fans start up

Estragon

That's a normal part of the bootup self test process on my OB VFXs - presumably also for your gear.

Still, making a sparky, erratic power-up connection instead of a clean breaker closing connection to boot likely isn't doing the gear any favours.

mevenable

The local guys seem to sell the stripped down version, figuring I guess that their customers wont pay extra for anything.  The Hub was not part of the original package, I had to figure out what was missing and ask for it.  They did not presume you would want to use Optics to view things from a computer.  In general, they sold an installed package that included the panels, CC, Inverter and batteries, as well as a breaker for the panels and a breaker for the entire fuse box (solar part, as well as the grid breaker).  There were also some general categories such as "battery connection kit" and "Electrical materials" which did not have any details.  Being a total neophyte, I assumed that everything needful was there, then have been finding out elsewise bit by bit.  The inverter and CC do not seem to be suffering for lack of the breaker boxes so far, but this must be what is affecting the hub, which is more delicate for some reason.

The local guys are really good in other aspects, they are very nice and fairly responsive over all (certainly compared to any other company I contacted for the work) and have worked with me to expand the original limited vision of the system to encompass a number of additional elements.  I would recommend them to others, with the caveat that I would recommend to anyone starting out with it to try to understand as much as possible yourself from the start.  Of course, like building a house (done that too), you never get it all right at first, and usually change your mind about a bunch of things as you go along.

Estragon

I get that you gotta sell what what people will buy. I get that safety doesn't (usually) sell. I'll even buy that these guys are legitimately trying to do "good" installs. That said, the added cost to add OCP to battery connection is minimal, and the cost of not doing it is not.

The great thing about this interweb thingy is people can learn why stuff works or doesn't, wherever they are. If they're any good, maybe they'll take the time to understand why having no OCP on a battery circuit is a bad thing.

Raj174

I know you said an Outback rep was there, but I have a hard time believing that Outback would approve of this installation especially since it was done by a retail company that sells their equipment. Did you call Outback to verify that they are an Outback dealer? I know I'm no actually addressing your posted question, but I believe you should have gotten the professional installation that you paid for.

Dave Angelini

Rick,
FYI  It is not that hard to become a dealer for Outback. It does not mean that you buy directly from Outback. They have little say in what is done and as you get south of Florida, It amazing how things seem to change very fast. This was the opposite that I thought until I lived there.

mevenable

the local installer, Ecami, is in fact working with Outback, they have a trainer that comes and works with then from time to time, and he even came to my farm and saw the system and never said anything about not having circuit breakers between the battery and the inverter and battery and charge controller.  They also have not been able to help me figure out the correct product to buy and install, and they are insisting that the lack of circuit breakers is not the problem that is blowing out the hub.  The Outback trainer guy says these are optional, although probably a good idea.  He said that it was probably a problem with improper grounding, and told me to send photos so Outback could figure out the problem and instruct Ecami in what to do to fix it.  However, he told me to take photos of the system from the "outside", with the covers on.  From this Outback experts said that I did not have any grounding at all.  There were conduits connecting everything, and I suspected the ground wires ran through that.  I took the tops off all the boxes and took photos illustrating that there were in fact green ground wires connecting everything. I sent those and never heard back, and when I called teck support they told me that Outback techs were not electricians, and could never tell what to do about grounding from photos, but that in any case they had already decided that grounding was the issue, and so the only thing to do was have Ecami come back out and find the problem.  They have not been able to do so, due to civil unrest, but in any case they have no idea what else to do with the grounding.  No one will instruct me on any tests I can do myself.  no one will even talk to me about the problem or respond in any way, since the day that they said that based on the photos taken of the outside of the system, there was no ground wires at all.  On top of this, I have been having a million problems with one of the twelve NC106 batteries, and can't get support on that either.  I will make a separate, new post for that next

Estragon

They may be right that having no breakers between inverter or controller and batteries isn't the problem with the hub. That said, making a sparky connection doesn't help rule it out, and it's a fire hazard in any case.

With a simple multimeter, you could check continuity on the ground wire, and check for a voltage difference between the negative and ground.

Are they by any chance making data cables on site? It's not hard to get a bad crimp or mixed up pinout on an ethernet plug, and needs a somewhat specialized tester to find.

mevenable

I have piles on CAT5 cables that came with the Outback products, and actually at the suggestion of the Outback Tech support I changed the one between the Inverter and the Mate3, for a different reason.  I am working without a hub for the moment, since I have not been able to resolve this in any way. I connected the inverter directly to the mate3s The Mate3s was 'glitching" constantly.  It would stop sending a signal to Optics, then would come back with 5000 kWh of load for that hour or something absurd like that, which did no other harm, but it kept me from being able to use the graph to look at anything else that day, since you would not see a 0.2 kWh load on a graph that included a 5000 kWh reading.  Also, it would sometimes just turn itself off for hours, and as a result it would not switch to grid when it was supposed to.  Anyhow, I reset to factory defaults and then reprogrammed everything, and switched the CAT5 cable, both on advice of tech support, but it did not solve the problem.  I started resetting the gateway from optics once or twice a day, and that has kept the problem under control, only one such glitch in the past few weeks.  This does not directly relate to what you said, but if it was a data cable issue, it would have apparently affected other things too.   Also, it is I believe significant that there was never any problem with the HUB EXCEPT when the local guys came by to work on things, never when it was just running.  The last time they burned it out, they had only added the third string of batteries, nothing else.

BB.

Estragon's suggestion to look at grounding and voltage between signal ground, battery ground, and hub+charger+inverter chassis grounds is a very good suggestion.

Use your voltmeter and a test light to see if grounds are floating or even accidently energized.

A common problem with RS 232 terminal to computer connections in larger installations is you could get 10's of volts between ac ground, battery ground, and ac ground 3 outlets away.

It was enough to pop the signal ground trace in the terminal RS 232 Port.

Bill

mevenable

sounds like you know what you are talking about.  Unfortunately, I am not that good to understand myself what I need to do next.

Dave Angelini

And here is the problem! You need to be very much in the know or you will continue to have issues. None of your installers work for Outback they work with them, or try to.

 Being trained and understanding the training are two very different things.

Usually this is best before the system is in but it looks like now is a good time to learn it.

Where is the surge protection?

BB.

Use a voltmeter to check the voltage between battery ground, case ground and signal ground (if you can access it in the cabling). It should be close to 0.0 volts. If it is over a couple of volts, then there may be a "grounding issue" (missing ground connection between battery negative and "system safety ground/chassis grounds of devices) or wiring problem (current flowing through "safety ground/green wire" instead of the battery - negative power cables).

I don't know what interface the Outback Hubs uses (or if you are connecting a PC or laptop computer to an RS-232 port)--But there are isolators for RS-232 and similar communications systems to help address grounding issues. The links below are examples used to isolate RS-232 ports and for sending the signals longer than normal distances... Not that they will solve your issue (or even fit your comm links). Just of an example of a particular grounding issue fix.

https://www.amazon.com/Powered-Serial-Electric-Isolator-protect/dp/B01EACRB0K
https://www.amazon.com/PhotoElectric-Isolator-Isolated-Isolation-Converter/dp/B016B43PZK

Grounding problems can be a difficult problem to solve.

Did you ever get a failure analysis from Outback on why the hubs failed?

And, as said above, fuses and circuit breakers missing from your system will not "save" the hubs. However, if switches or circult breakers are installed in the "wrong place", the could cause this sort of issue (normally, switches and breakers are only installed in the + positive battery connections. All - negative connections should be solid back to the battery negative bus. If you switch the negative leads to a hub/charge controller/ac inverter/etc., this can cause the "ground shift" and blow communications circuits).

-Bill

Estragon

It may be best to just insist the local installers get the system working properly if you don't have the knowledge to work on it safely. With no breakers between devices and batteries, the only way to de-energize would be to lift connection(s) to batteries. Poking around a live system when you don't know what you're doing may be unwise.

As Bill said, my thought is ground at the hub might be at a significant potential with respect to power or signal conductors. It will be designed for low voltage (likely 5v) only. Ground should be at or near the same potential as negative, but may not be. A few tens of volts between ground and hub potential might well cause a hub to fail. It could also cause failures in the networking parts of the inverter and/or controller. Checking for this may involve opening boxes and checking voltages with a multimeter though.

One thing you might be able to check (carefully) without opening anything is voltage between the battery negative connection and an exposed (unpainted) metal part of the inverter and/or controller. Set the meter initially to a large voltage scale (eg 200v), then if reading zero or nearly zero, switch to lower voltage (eg 20v and 2v) scale. You could also test for voltage between exposed metal parts of the various devices and panels.