Hey all,
To close the loop on this, I doesn’t look like its a “Power Save” setting as
those are available on Grid-Tied FX’s. I went yesterday and confirmed that
just Inverter #2 is pushing power when grid-tied ( 21A at 120V is what I
tested at the time), however both start inverting (indicated by green LED) when
grid-goes down. But it seems to be functioning like the Power Save modes and
shutting down Inverter #1 when grid-tied.
My best guess is since the array is only 4.2KW and a shallow roof and never
really hitting that 4.2KW peak (2.0-3.0KW typical on a sunny day), it’s only
running the power through 1 of the inverters because it only needs to run 1.
There are no errors, or warnings on Inverter 1, and what’s weird is even when I
switch the inverter ports on the Hub (swap 1 and 2), Inverter 2 is still the
only one that’s inverting typically. The exception was when I was testing I
shut off grid power for a few minutes to test the backup function, during which
the batteries did an absorb charge. When I reconnected the grid the inverters
started to sell some of that battery power(for a minute), along with the PV,
down to the sell voltage. Then once the voltage leveled out, inverter #1 went
to sleep again.
If this was Myth Busters I would say “Plausible” because I’m not really sure… :)
Thanks for your brains!
Amos
Amos Post
Integrity Energy
W 802.763.7023
C 802.291.2188
ienergyVT.com <http://www.ienergyvt.com/>
Facebook <https://www.facebook.com/integrityenergyllp?ref=hl>
> On May 12, 2025, at 12:53 PM, Amos Post <[email protected]> wrote:
>
> Oh I forgot to mention the inverters are side x side on 2 individual Panels….
> <IE LOGO 150x78.jpg>
>
> Amos Post
> Integrity Energy
> W 802.763.7023
> C 802.291.2188
> ienergyVT.com <http://www.ienergyvt.com/>
> Facebook <https://www.facebook.com/integrityenergyllp?ref=hl>
>
>> On May 12, 2025, at 12:48 PM, jay via RE-wrenches
>> <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>> good point.
>> For GT OB systems I have removed the side screens for better air flow and
>> I’ve also taken the covers off and used external fans to cool them.
>>
>> They just were not designed to run anywhere near rated capacity for long
>> periods of time, they don’t have enough air cooling.
>>
>>> On May 12, 2025, at 10:41 AM, Ray Walters via RE-wrenches
>>> <[email protected]
>>> <mailto:[email protected]>> wrote:
>>>
>>> Is inverter 2 on top? The top inverter in an Outback dual stack always
>>> runs hotter, because the heat from the bottom inverter is adding to its own
>>> heat. I used to see that consistently cause board failures on the top
>>> inverter more often, if the whole system was running close to capacity.
>>>
>>> Ray Walters
>>>
>>> On 5/12/2025 7:56 AM, Amos Post via RE-wrenches wrote:
>>>> UPDATE:
>>>>
>>>> So far so good and since replacing the fuse holder, fuse #3 has not blown
>>>> again.
>>>>
>>>> ANOTHER ISSUE:
>>>>
>>>> Inverter 2 runs hotter than inverter 1. Reminder this is grid-tied
>>>> system with 2-GVFX3648’s in series for 120/240V. The fan on inverter #2
>>>> had malfunctioned, but I was able to replace it and get that going again.
>>>> Even with the replaced fan, inverter #2 is still running noticeably
>>>> hotter. My understanding is that both inverters in this system are
>>>> essentially “Masters”, since this is grid-tied. Shouldn’t the
>>>> load/generation be split between the two and hence they run equally as
>>>> hot? I did check the stacking and they were both set to “Master” which is
>>>> I think what they recommended for grid-tie. I tried switching the ports
>>>> on the Hub that they are plugged into to see if that would change
>>>> anything, but no change. I did also noticed while I was there last week
>>>> that while both inverters had the solid yellow “AC IN” light on, inverter
>>>> #2’s green “Inverter” light was always on, while inverter #1’s green
>>>> “Inverter” seemed to come and go…
>>>>
>>>> Any ideas?
>>>>
>>>> Thanks as always,
>>>> Amos
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> <IE LOGO 150x78.jpg>
>>>>
>>>> Amos Post
>>>> Integrity Energy
>>>> W 802.763.7023
>>>> C 802.291.2188
>>>> ienergyVT.com <http://www.ienergyvt.com/>
>>>> Facebook <https://www.facebook.com/integrityenergyllp?ref=hl>
>>>>
>>>>> On Apr 15, 2025, at 8:40 AM, Amos Post <[email protected]
>>>>> <mailto:[email protected]>> wrote:
>>>>>
>>>>> Hi all,
>>>>>
>>>>> I decided to start with the simple stuff. While I don’t have a string
>>>>> curve tester (I should have one), yesterday I tested strings 1,2,3
>>>>> individually under load. String 3 is the one that’s been blowing the
>>>>> fuse. I did not test strings 4-6 which are on a separate charge
>>>>> controller and combiner. Here are the results:
>>>>>
>>>>> String 1- 7.1A at 76V
>>>>> String 2- 7.77Aat 79V
>>>>> String 3-7.13A at 78.3V
>>>>>
>>>>> I did notice that the second charge controller with strings 4-6 was
>>>>> running about 100watts more (1800w vs 1700w). The conditions were clear
>>>>> blue skies. I replaced the fuse holder and fuse. If it blows again I’ll
>>>>> try switching strings to see if it follows…
>>>>>
>>>>> Thanks for your feedback and I’ll keep ya’ll posted.
>>>>>
>>>>> Amos
>>>>>
>>>>>
>>>>> <IE LOGO 150x78.jpg>
>>>>>
>>>>> Amos Post
>>>>> Integrity Energy
>>>>> W 802.763.7023
>>>>> C 802.291.2188
>>>>> ienergyVT.com <http://www.ienergyvt.com/>
>>>>> Facebook <https://www.facebook.com/integrityenergyllp?ref=hl>
>>>>>
>>>>>> On Apr 11, 2025, at 4:07 PM, Jerry Shafer via RE-wrenches
>>>>>> <[email protected]
>>>>>> <mailto:[email protected]>> wrote:
>>>>>>
>>>>>> Wrenches, Amos, blowing of a 15 amp fuse is not a ghost in the machine,
>>>>>> it is an actual issue no way around it, shorted modules, shorted diodes,
>>>>>> in most cases it's a home run, way back when USE-2 white wure was
>>>>>> failing and would crack and break off mostly this would result in a GFI
>>>>>> trip. The fuse is blowing because of over current and a single string of
>>>>>> your vintage will max out at far less than 10 amps but the other two
>>>>>> strings will back feed this fuse with close to 20 then pop.
>>>>>> Sharp had module failures resulting in cell shorts, look very close
>>>>>> there. I have inspected arrays with extreme exposure differences, this
>>>>>> will effect performance but should not pop a fuse. Do you have a module
>>>>>> string curve tester, this very well may show an issue of the string but
>>>>>> eyes on the array is required to located the cause.
>>>>>> I have seen nails through wires, conduit, racking in contact with the
>>>>>> back of the module but this will trip the GFI breaker not the string
>>>>>> fuse.
>>>>>> Fun times.
>>>>>>
>>>>>>
>>>>>> On Fri, Apr 11, 2025, 12:49 PM david quattro via RE-wrenches
>>>>>> <[email protected]
>>>>>> <mailto:[email protected]>> wrote:
>>>>>> One time I had similar, but different problem: 1 Amp ground fault fuse
>>>>>> consistently blowing, sometimes after 1 day sometimes after
>>>>>> weeks/months. I tried everything - replaced home runs, checked VOC,
>>>>>> VMP, swapped DC input into a different inverter, etc. it kept coming
>>>>>> back to this one string. I checked every module VOC, ISC, every
>>>>>> connection, no pinched wires, no discernible problem, but fuse blowing.
>>>>>> Luckily it was a medium size commercial job (on a fire station) so I
>>>>>> was able to scatter all the modules of this suspect string all over the
>>>>>> roof, and carefully track where I had put them. That’s when the problem
>>>>>> went away and never came back..😂
>>>>>> Best I could figure was a slight manufacturing error that had a
>>>>>> compounding/cumulative effect. So once I got those consecutive serial
>>>>>> numbers away from each other no more problem. Either that or the fire
>>>>>> chief was fucking with me and he was burning out the fuses, which I
>>>>>> doubt
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Fri, Apr 11, 2025 at 8:05 AM Mac Lewis via RE-wrenches
>>>>>> <[email protected]
>>>>>> <mailto:[email protected]>> wrote:
>>>>>> Hello Amos,
>>>>>>
>>>>>> Have you checked for voltage imbalance for each string? If you have a
>>>>>> bad diode, that string may run low on voltage and be trying to send
>>>>>> current toward the weak string (this is the reason you have these
>>>>>> breakers). I'd run each string independently and see what Vmp is. If
>>>>>> you are missing some voltage that may be a clue. You can also
>>>>>> independently clamp each string during operation.
>>>>>>
>>>>>> I like IR cameras for this type of thing. It may just be a bad
>>>>>> connection, heat build up, fuse holder issue.
>>>>>>
>>>>>> Let us know what you find out
>>>>>>
>>>>>> On Fri, Apr 11, 2025 at 8:07 AM Amos Post via RE-wrenches
>>>>>> <[email protected]
>>>>>> <mailto:[email protected]>> wrote:
>>>>>> Hi Wrenches,
>>>>>>
>>>>>> I have a bit of a puzzler that I’m trying to get sorted out. I’ve been
>>>>>> servicing a Grid-Tied Battery Backup system that’s about 17-18 years
>>>>>> old. The system comprises of 2-GVFX3648s in series, with 2-MX60(at
>>>>>> least I think they are 60s) CC’s. Each CC has 3 strings of 3 tied to
>>>>>> it, and each string has a 15A in-line 600V fuse. The modules are I
>>>>>> believe are like 230/240Watt 60 cell modules (sorry I don’t have
>>>>>> pictures/specifics). We replaced the flooded batteries with AGMs about
>>>>>> a year and a half ago.
>>>>>>
>>>>>> The situation is one of the 15A string fuses keeps blowing. It’s now
>>>>>> happened 3 times and its the same fuse every time. First we just
>>>>>> replaced the fuse and under the surge/lightning assumption. Fuse blew
>>>>>> again. Then I thought I found the culprit. The #6 PV output from the
>>>>>> combiner to the PV input breaker for the CC was a bit darkened and very
>>>>>> warm to the touch when I replaced the fuse the first time. So I though
>>>>>> maybe it was a loose connection on that lug and that caused everything
>>>>>> to heat up and eventually blow the fuse. I cut and stripped the wire
>>>>>> back and cleaned the lug and re-seated the wire in the lug. Fuse blew
>>>>>> again within a few months time. I then checked the Junction box on the
>>>>>> roof where the USE-2 wire connects to THHN, and did a visual inspection
>>>>>> of all the wiring on the roof. All of the Jbox connections and
>>>>>> everything on the roof “looked” ok. I have also check all of the
>>>>>> connections inside the Outback DC load center, and they look ok. Fuse
>>>>>> replaced 3rd time and then it blew again.
>>>>>>
>>>>>> Before I take all of the panels off the rack, check panels, re-check
>>>>>> string wiring on the roof, is there anything else I should be checking?
>>>>>> Seems like that warm wire in the Combiner box is telling me something
>>>>>> but I can’t figure out what...I believe this is a new problem in the
>>>>>> last 2-3 years but we are not 100% sure when the problem first came up…
>>>>>>
>>>>>> As always, thanks for your help/ suggestions!
>>>>>> Amos
>>>>>>
>>>>>>
>>>>>> <IE LOGO 150x78.jpg>
>>>>>>
>>>>>> Amos Post
>>>>>> Integrity Energy
>>>>>> W 802.763.7023
>>>>>> C 802.291.2188
>>>>>> ienergyVT.com <http://www.ienergyvt.com/>
>>>>>> Facebook <https://www.facebook.com/integrityenergyllp?ref=hl>
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>>>>>> --
>>>>>>
>>>>>>
>>>>>>
>>>>>> Mac Lewis
>>>>>>
>>>>>> "Yo solo sé que no sé nada." -Sócrates
>>>>>>
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