KJ2 Posted July 24, 2020 Posted July 24, 2020 I have a Mecer 5kva inverter and 10x400w panels. We get error code 11 every day which is 'Main relay failed' (this could be at any time of the day). The electricians have checked all the hardware, replaced breakers, and also taken in the inverter to mustek and everything is 100%. We also re-installed the panel strings but still no change. I have read up in this and could be one of the following reasons: Could be due to the PV voltage going above the max 450V stipulated - please can someone confirm if this could be the case? In the mornings when it runs on max voltage I see it goes up to about 448 but I understand the inverter could handle going slightly above the 450? The electricians are recommending to split the strings, ie split the voltage? Will this help to address point 1? Could be a faulty panel but we have checked each panel and the voltage etc is perfect. I am not an electrician and reading up on these so any assistance will be appreciated. Thanks Quote
Coulomb Posted July 24, 2020 Posted July 24, 2020 3 hours ago, KJ2 said: I have a Mecer 5kva inverter and 10x400w panels. We get error code 11 every day which is 'Main relay failed' (this could be at any time of the day). On your model, which I had to guess is an Axpert MKS II equivalent (SOL-I-AX-5NB probably), it means "PV over voltage". Quote Could be due to the PV voltage going above the max 450V stipulated - please can someone confirm if this could be the case? Certainly. It won't even operate at full power until the voltage falls to 420 V, as measured by the inverter, not your multimeter, of course. It could be slightly inaccurate. Quote In the mornings when it runs on max voltage I see it goes up to about 448 but I understand the inverter could handle going slightly above the 450? As far as I am aware, 450 V is the "never exceed" voltage. Parts could be rated for 450 V max. Quote The electricians are recommending to split the strings, ie split the voltage? Will this help to address point 1? Yes. This is the solution. 5S2P of your giant panels should be fine. Quote
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