Spanish Flyer
New Member
Dear Colleges,
My inverter "collection" is composed of several inverters; I started in 2017 and a lot of mods and adaptations have taken place since then; right now I have four inverters, all connected to the same grid and each one taking care of their share, from my 7 strings coming from the roof.
For more than two years I've had the two Kostal Piko MP Plus 5.02 running together and taking care of 4 of the seven strings; nothing has changed since I installed them and they worked flawlesly since they were put into operation; I use a KSEM Kostal Energy Meter that takes care of both and makes sure I have ZERO EXPORT to the grid.
The problem: About a month ago one of the inverters started giving a fault, stating that the DC current was too high; these inverters can hande up to 600 V DC from the panels... Using a tester, the maximum voltage I could read was 530 V DC. Contacted Kostal and sure enough they guided me into changing the tolerance of the inverter, but that did not cure the problem. I then purchased a brand new unit (Piko MP plus 5.02) and what do you know, it gave the exact same problem after less than 15 minutes running... So it was not the inverter. Then what??? As I mentioned, that inverter had been running without problems with the same two strings for at least 24 months....
On the other hand I know if anything, the solar panels tend to loose some of their performance as they age and again, 530V is far from the maximum 600V DC that these inverters can handle.
Right now I'm using the original inverter but with one of the strings removed (taken the fuses out).
My question is, What is happening with this string, set of panels or whatever, because I have run out of ideas; worst of all, I'm not getting all the energy that my roof panels produce.
Thanks for your attention
My inverter "collection" is composed of several inverters; I started in 2017 and a lot of mods and adaptations have taken place since then; right now I have four inverters, all connected to the same grid and each one taking care of their share, from my 7 strings coming from the roof.
For more than two years I've had the two Kostal Piko MP Plus 5.02 running together and taking care of 4 of the seven strings; nothing has changed since I installed them and they worked flawlesly since they were put into operation; I use a KSEM Kostal Energy Meter that takes care of both and makes sure I have ZERO EXPORT to the grid.
The problem: About a month ago one of the inverters started giving a fault, stating that the DC current was too high; these inverters can hande up to 600 V DC from the panels... Using a tester, the maximum voltage I could read was 530 V DC. Contacted Kostal and sure enough they guided me into changing the tolerance of the inverter, but that did not cure the problem. I then purchased a brand new unit (Piko MP plus 5.02) and what do you know, it gave the exact same problem after less than 15 minutes running... So it was not the inverter. Then what??? As I mentioned, that inverter had been running without problems with the same two strings for at least 24 months....
On the other hand I know if anything, the solar panels tend to loose some of their performance as they age and again, 530V is far from the maximum 600V DC that these inverters can handle.
Right now I'm using the original inverter but with one of the strings removed (taken the fuses out).
My question is, What is happening with this string, set of panels or whatever, because I have run out of ideas; worst of all, I'm not getting all the energy that my roof panels produce.
Thanks for your attention
