[RE-wrenches] Sol-Ark 15K2P F20 MPPT Overcurrent Error

[Tyrone Houck]

Vince,
The f20 overcurrent error can also be a product of a loose or undersized
battery cable(or not using a Y buss on the battery terminals) or the
inverter trying to pull more current under load than bms allows(check max
discharge amps vs battery/bms ratings). Limit to home mode can also cause
an issue under abrupt switching of large AC loads-the confounding "High
voltage DC buss" limitation of AIO inverters. I have noticed this when an
AIO is trying to support input side main panel loads.
If none of those things inform the diagnosis it may need a firmware update.
Best of luck!



On Fri, Apr 10, 2026, 7:08 PM Vince McClellan via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Hi David
> I appreciate your help. I hadn't thought of swapping strings because the
> MPPT channel that is triggering the F20 error is always different. It could
> be worth a try anyway as it's easy to do. I do think we're down to swapping
> the inverter to see if that clears the issue.
>
> Sol-Ark hasn't been much help on this one.
>
> Have a great weekend,
>
>
> Vince McClellan
>
> President
>
> NABCEP PV Professional
>
> p: 541-485-8122
>
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>
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>
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> On Fri, Apr 10, 2026 at 4:54 PM david quattro <david at quattrosolar.com>
> wrote:
>
>> i would swap which strings go into the different MPPT's to see if each
>> specific problem follows the DC string // or do they follow the MPPTs.
>> Another option is kinda a lot of work but might be worth it - take a
>> different inverter out there and "bench test" it with those strings
>> unadulterated
>> Good luck and please let us how this one resolves.
>>
>>
>>
>> On Fri, Apr 10, 2026 at 4:05 PM Vince McClellan via RE-wrenches <
>> re-wrenches at lists.re-wrenches.org> wrote:
>>
>>> Hello Wrenches
>>> Has anyone else on this list had issues with a Sol-Ark 15K2P randomly
>>> shutting down several times a day with an F-20 MPPT overcurrent error? The
>>> errors are occurring when the system is well under the max amperage per
>>> MPPT of 26 amps. We've had the inverter turn itself off when the online
>>> data shows 12.5 amps max. I realize that Sol-Ark's online data updates only
>>> every 5 minutes, so I could be possible that there is a spike that the
>>> online data isn't showing, but the array is in full sun with the same
>>> number of modules and the same string configuration on all 3 MPPT's.
>>>
>>> We are also seeing other anomalies such as MPPT 1 at 12 amps with MPPT 2
>>> and 3 at 22 amps. Again, with the solar array in full sun, no clouds, and
>>> no shade.
>>>
>>> Sol-Ark originally thought it was because of an issue with Tigo RSD
>>> switches, but we don't use Tigo. We've had way too many issues with Tigo
>>> products.
>>>
>>> We've had people suggest that we're seeing the results of an edge of
>>> cloud affect, but there are not clouds to cause this.
>>>
>>> We've also tested all the circuits with a insulation tester in every
>>> possible configuration, and tested our wiring to insure there were no
>>> mistakes by ringing it out with a multimeter. The wiring is good.
>>>
>>> Sol-Ark tech support doesn't seem to know what the issue is, but they
>>> are assuring us that it's not their inverter at fault.
>>>
>>> I could use any suggestions that come to mind. I'm not sure what else to
>>> try at this point.
>>>
>>> Thank you,
>>>
>>>
>>> Vince McClellan
>>>
>>> President
>>>
>>> NABCEP PV Professional
>>>
>>> p: 541-485-8122
>>>
>>> a: 860 Conger St. Suite 12,. Eugene, OR 97402
>>> <https://www.google.com/maps/search/860%0D%0AConger+St.+Suite+12,.+Eugene,+OR+97402?entry=gmail&source=g>
>>>
>>> e: vince at solarenergydesgin.com
>>>
>>> w: SolarEnergyDesign.com
>>>
>>> CCB# 161672
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