Oh I forgot to mention the inverters are side x side on 2 individual Panels….
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]> 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]> 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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>>>>> --
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>>>>>
>>>>>
>>>>> Mac Lewis
>>>>>
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>>>>>
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