Learning the hard way - twice

jcheil
jcheil Solar Expert Posts: 722 ✭✭✭
So I was helping my neighbor replace his inverter this past weekend. Not a fancy one or anything.
But ran into an issue and thought I would share it with everyone.

He has a C60 controller. I know that would normally not have anything to do with what I am talking about, but read on.
So his son was helping and was wiring up a new plug for the inverter (standard NEMA-15 plug).

Plugged it in, turned on the power, and it all worked fine...for about 5 seconds...then POOF, smoke coming out of the C60.
Sadly, I know what happened, because I had done a similar thing years ago when I had a c60.

Investigation showed that when he wired the plug, a couple strands of the wire from the hot wire were out of the screw and touching the ground terminal in the plug. That caused AC from the inverter to feed back thru the ground wire and go into the C60 and burn up the capacitor right at the bottom of the main board where the negative PV/Battery connections are.

I did this (somewhat) same thing with mine years ago in that I had a variety of AC and DC shunts and meters and 2 voltage monitoring/logging boards. I accidentally put one of the AC shunt sense wires on the DC board and it fed ac back to the C60 and blew the same capacitor.

I had forgotten all about that when I was helping him, and I (since my mistake back in the day) have always had a separate ground for DC vs AC. I know there has been discussions here and maybe even NEC says they ALL should ground to the same point. But I would wonder if this same thing would happen in the case if, for example, a toaster shorted hot to ground. I would think that would send the same AC thru the ground wires, thus ending up back at the C60?

Or what about the fact that ground and neutral are bonded (at some place) - Wouldn't that mean that there is always a bit of AC in the ground wire anyways? Or perhaps it has something to do with if the inverter itself has bonded ground/neutral inside it. I bet on his it was because it was a small, cheap inverter with just 2 Nema-15 receptacles. I have no idea.

Just wondering your thoughts. Ever since my issue I have always kept my AC and DC grounds completely separate (two different ground rods). Or perhaps this was all just a fluke and there is something else, but it just seems to fit the situation.
Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Learning the hard way - twice

    What type of AC inverter? Was it MSW or TSW? The TSW inverters tend to have DC input to AC output isolation (through a transformer).

    MSW inverters tend not to have isolation and if you ground reference one of their AC outputs, it will put an AC voltage/current the DC input (and if DC to AC "grounds/neutrals are bonded", it will usually smoke the AC inverter).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: Learning the hard way - twice
    BB. wrote: »
    What type of AC inverter? Was it MSW or TSW? The TSW inverters tend to have DC input to AC output isolation (through a transformer).

    MSW inverters tend not to have isolation and if you ground reference one of their AC outputs, it will put an AC voltage/current the DC input (and if DC to AC "grounds/neutrals are bonded", it will usually smoke the AC inverter).

    -Bill

    It was a cheap, China, MSW inverter. I know...don't say it. I told him, but unfortunately he is always on the super-cheap side.
    The previous one was a cheap MSW also, but didn't have any problems (until it blew up on its own).
    This time I am sure it was because of the plug miswire.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Learning the hard way - twice

    Sounds like it put AC power on the DC Battery bank line (with respect to your green wire AC ground). I am not sure if it put 12 VAC or 120 VAC on the DC side when one of the AC outputs was ground referenced--But that is probably what took out the C60 controller.

    Technically, this is why I always say to ground bond the DC ground and AC grounds together (in one spot).

    In this case, it probably would have saved the C60 (and prevent a possible shock hazard on the DC battery bank side if the C60 did not fail).

    However, on the other side, a hard AC+DC ground bond could have very easily taken out the MSW AC inverter...

    Not a great solution in either case--But overall safety would (in my humble opinion) would have been better served if the AC+DC grounds were bonded.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: Learning the hard way - twice
    BB. wrote: »
    Sounds like it put AC power on the DC Battery bank line (with respect to your green wire AC ground). I am not sure if it put 12 VAC or 120 VAC on the DC side when one of the AC outputs was ground referenced--But that is probably what took out the C60 controller.

    Technically, this is why I always say to ground bond the DC ground and AC grounds together (in one spot).

    In this case, it probably would have saved the C60 (and prevent a possible shock hazard on the DC battery bank side if the C60 did not fail).

    However, on the other side, a hard AC+DC ground bond could have very easily taken out the MSW AC inverter...

    Not a great solution in either case--But overall safety would (in my humble opinion) would have been better served if the AC+DC grounds were bonded.

    -Bill

    They were in this case, and that is what I was thinking allowed the AC to fry the C60.
    All the grounds for everything (AC, DC, Frames) were to one common point/rod.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Learning the hard way - twice

    Then I am not sure what took out the C60...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: Learning the hard way - twice
    BB. wrote: »
    Then I am not sure what took out the C60...

    -Bill

    So are you saying that if ALL grounds (AC/DC/Frame) were to one point, there can never be a chance of the AC and DC getting mixed up and back-feeding into all the other devices in a fullt condition like the mis-wired plug in this case?

    And furthermore, are you saying there is a possibility that with a cheap MSW inverter it could send AC back out thru the battery terminals into the bank (and thus up to the C60)?

    Sorry for ignorance, I just hate mysteries.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: Learning the hard way - twice

    And forgot to mention, the C60 still "appears" to be "working" :) [But will be ordering a new one today]
    Maybe the cap shorted closed. Not sure what it's design was for but I am sure it is for something.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Learning the hard way - twice

    The TSW inverters typically have full transformer isolation... So if you ground reference one AC output--It has no impact on the DC input.

    For MSW, they do not have isolation transformers--They (I am guessing) have some sort of auto transformer (non-isolated step up) which, if you sort one AC output and ground reference the output back to the Negative (or positive) battery bank, when there is an AC output to ground short, there is (more or less) dead short between the positive battery bus, through a couple of FETs and heavy transformer/inductor in the MSW inverter back to earth ground (and battery negative bus).

    If the battery bus is not grounded, the MSW inverter can "shake" the DC Battery bus up and down (because of the AC output is not ground referenced). Whether it does it by 12 volt or 60 volt or 120 volts AC--I am not sure... But if there are bypass capacitors in the C60 to earth ground (not uncommon method to reduce radio frequency emissions), these filter caps can be over voltaged (normally, there should not be more than a volt or two between DC ground and DC safety ground if you ground reference the battery bank). So, you might find they use between 6 and 50 volt bypass capacitors and possible a resistor for static discharge (at least, that is what I would do).

    Otherwise, if the AC and DC share grounds--You can get high DC current through your AC safety wire (i.e., 10 amps of 120 VAC becomes 100 amps of 12 VDC current--and your 14 AWG ground wire could smoke).

    How this would smoke a C60--I don't see any easy to explain way of doing. The C60 should be (at worse) seeing the same DC current from the solar array (solar panels being, more or less current sources, would not output much more than Isc if the battery + output was near zero volts).

    Not saying it cannot happen... I just don't see how. If you had remote battery temperaure sensor get somehow over voltaged or other "signal" wiring from the C60 (like a remote meter interface)--Possibly a ground offset of 5-10 volts could smoke the insulation on a signal/ground reference wire. We had this happen fairly regularly with RS 232 comm cables and video terminals--The large computer (like telephone switch gear) was on one earth ground and the terminal/printer was on another earth ground (I have seen >60 VAC between two ground rods 100' apart in industrial settings).

    Or if there was a "broken ground" connect to the ground rod (bad cable/plug/etc.) could also cause it.

    If you pull the C60 apart, you may find what smoked and that could give you some more information.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: Learning the hard way - twice
    BB. wrote: »
    If you pull the C60 apart, you may find what smoked and that could give you some more information.

    -Bill

    It was only the one cap that is smoked. I will take a pix and post it in a few mins.
    Like I said, strange it still "seems" to be working :)
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Learning the hard way - twice

    I can see a case where if the DC (-) is grounded and the AC output touched ground (there should be no N-G bond on an MSW inverter) it could cause a momentary high Voltage on the DC output of the C60 similar to a lightning-induced event and possibly just enough to pop a capacitor.

    Usually such a short would fry the MSW inverter, but perhaps it wasn't present long enough to do that.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: Learning the hard way - twice
    I can see a case where if the DC (-) is grounded and the AC output touched ground (there should be no N-G bond on an MSW inverter) it could cause a momentary high Voltage on the DC output of the C60 similar to a lightning-induced event and possibly just enough to pop a capacitor.

    Usually such a short would fry the MSW inverter, but perhaps it wasn't present long enough to do that.

    I think that is exactly what happened. and the moment the smoke came out, we killed power to the inverter. So that might have saved the inverter. Pix coming in a few mins.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Learning the hard way - twice

    See if you can figure out where the capacitor is located (between +/- on the battery, between green wire and battery, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: Learning the hard way - twice

    As expected, it stopped working last night. Surprised that it had run for so long actually!

    It "looks" like that cap is connected to the NEG sides. I read continuity from one of the legs to the neg terminal, but then again, the cap is blown so it could be just a dead short at this point. Also this level of technical detail is not my thing.

    Attachment not found.
    Attachment not found.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: Learning the hard way - twice

    On learning the hard way, reading the title of this thread reminded me of a quote by Mark Twain:

    Paraphrasing to compensate for failing memory, it is: "A man who carries a cat by the tail learns a lesson that he cannot learn by any other method."
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: Learning the hard way - twice

    Ok, found some more information.

    The cap that blew out was labeled on the circuit board as TVS2 (there is a TVS1 next to it that was fine). Not sure what that stands for.

    So we got the new C60, but before installing it, I wanted to really make sure it wasn't going to happen again. We were 99% sure that the incorrectly wired plug was what caused it, but I wasn't going to take a chance. So, started testing everything and found out that even with the correctly wired plug, there was still 75vac going from DC neg to ground. DC neg was NOT bonded to ground in this system which might explain why the inverter did not blow up as someone else mentioned.

    Well long story short and after 8 hours of testing every circuit in the cabin looking for ground faults, etc, trying to figure out how 75v ac was getting on the ground wire, it turned out that the same person that wired the plug also had wired the junction box where the cable from the inverter plug connects to the house panel. He had tightened the box connector so tight that it cut the insulation on the neutral. And being that it was a metal junction box, and the ground was connected to the junction box, THAT was feeding it back thru the ground. What was even more interesting is that it never caused the inverter to fault, or trip any breakers. And the voltage varied. Seemed like it was 75v with no ac loads running, but then it would drop to lower amounts when loads (on the ac side) were on.

    After hours of trying to find wiring problems (and found many hot/neutral reversed, etc), it got do to the point where there was only 15vac from DC neg to ground. I still have no idea where that is coming from and recommended that he hires a REAL electrician. We DID bond the dc ng to ground and obviously, that eliminated the 15vac reading but I am not sure that everything is still "right". I say this because when the DC neg and ground were NOT bonded, the cheap circuit tester, plugged into an inverter outlet showed correct wiring (at the inverter). but as soon as we bonded the DC neg to ground, then all 3 lights on the tester lit up (which does not even have a reading on the scale to show what that means!?!?). PS - To the best of my knowledge, there are no INTENTIONAL N-G bonds anywhere in the house wiring/panels. And if we tried to install the bonding screw in the main panel, the inverter would fault (which from what i read is typical as MSW inverters tend to be bonded already I believe).

    I just gotta say again to ANYONE reading this and thinking of installing a system/inverter: These cheap China MSW inverters are NOT worth it! If I were being paid for this, I would have had to charge someone for 8-10 hours of labor which would have EASILY been more than the cost of a med-high quality, non-china, TSW inverter.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Learning the hard way - twice

    Get a filament lamp and connect it between DC Negative and Ground--If the 15 VAC is just a little capacitance causing the AC--The 120 VAC 20-60 watt bulb will "short out" the small amount of AC current.

    If you still have a Hot/Neutral to ground short on the AC side, the bulb will not short out the current and you will still measure the 15 VAC. But the bulb should prevent a dead short from causing any damage.

    All three lights lit on the tester--Sounds like what I would expect for a MSW inverter with the AC "floating" (correctly installed, no Neutral to earth bonding) and having DC return earth grounded.

    Sounds like a wiring nightmare.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Learning the hard way - twice
    jcheil wrote: »
    I just gotta say again to ANYONE reading this and thinking of installing a system/inverter: These cheap China MSW inverters are NOT worth it! If I were being paid for this, I would have had to charge someone for 8-10 hours of labor which would have EASILY been more than the cost of a med-high quality, non-china, TSW inverter.

    I say that often. For some reason people don't listen. MSW just isn't worth the "savings" anymore.
  • bill von novak
    bill von novak Solar Expert Posts: 891 ✭✭✭✭
    Re: Learning the hard way - twice
    jcheil wrote: »
    The cap that blew out was labeled on the circuit board as TVS2 (there is a TVS1 next to it that was fine). Not sure what that stands for.

    Transient voltage suppressor. Conducts only when voltage exceeds a certain limit.
    He had tightened the box connector so tight that it cut the insulation on the neutral. And being that it was a metal junction box, and the ground was connected to the junction box, THAT was feeding it back thru the ground. What was even more interesting is that it never caused the inverter to fault, or trip any breakers.

    Makes sense if the DC side was not grounded. If neutral and ground are connected BUT the case of the inverter and/or DC negative is not grounded, then the system could be "running" the case/DC negative up and down by 100 volts or so. If the inverter was not grounded but the charge controller was, that could blow the MOV's/TVS's.
    So we got the new C60, but before installing it, I wanted to really make sure it wasn't going to happen again. We were 99% sure that the incorrectly wired plug was what caused it, but I wasn't going to take a chance. So, started testing everything and found out that even with the correctly wired plug, there was still 75vac going from DC neg to ground.

    When doing tests like this you will often see "irrational" voltages when there are no ground connections. For example, if you measured between your car's ground to an earth ground you might see 20 volts - and it might change as you moved around! What you are seeing is not a serious issue; you're seeing in effect the static potential of the car, which bears no resemblance to earth ground. This gets people sometimes because they then think there's a shock hazard or something.

    However, once you introduce any resistance at all (say a 100 ohm resistor) that number would quickly go to zero as the potentials reached equilibrium.

    That's one reason grounds are important - to provide a fixed reference for measurements.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Learning the hard way - twice
    That's one reason grounds are important - to provide a fixed reference for measurements.

    And always remember that ground conductors have resistance too; if it gets too high the Voltage reference between 'ground and ground' (two points in a system that are supposed to be grounded) may not be zero.

    Which is what I think we're trying to track down in the other thread.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: Learning the hard way - twice

    Yup all that makes sense now. I am actually glad that you all could explain the "whys" of this failure.
    I hate mysteries personally. And even worse, I hate when there is a problem and then suddenly it disappears and starts working on its own.

    Hopefully new people can learn from these "mistakes" by reading these threads.

    Thanks again for all the help.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: Learning the hard way - twice
    Transient voltage suppressor. Conducts only when voltage exceeds a certain limit.

    Do you have any idea if replacing that TVS would bring the unit back to life or would you think there could be other issues?
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Learning the hard way - twice

    Check for smoke/flame damage... The surge suppressor probably has no functional tasks in the controller--Just for safety.

    My other suggestion, get a Current Clamp Meter and measure "circulating currents"... Basically measure green wire current (should be almost none) and clamp around Hot/Return lines to see if there is a net current flow (again, current should be near zero).

    Make the readings on both DC and AC scales (if this is a DC off grid system).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • bill von novak
    bill von novak Solar Expert Posts: 891 ✭✭✭✭
    Re: Learning the hard way - twice
    jcheil wrote: »
    Do you have any idea if replacing that TVS would bring the unit back to life or would you think there could be other issues?

    I don't know. If the issue was only + and - potential to ground then it might well fix everything. For a simple test remove the TVS completely and run the system with ONLY the panels and the batteries connected (to avoid the same problem.) If it works, then that's your problem, and replacing it will fix it. TVSes typically provide lightning/transient protection. Although on most devices it protects from nearby strikes only; most will not survive a direct strike.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Learning the hard way - twice

    One problem with any circuit that's been hit with high Voltage: even the components that didn't fail immediately may be stressed and therefor more likely to fail sooner rather than later.

    For a non-critical application you might want to try and replace the cap and see if it works, but don't get your hopes up and don't expect it to last long even if it does work.