Started getting this problem today. Power goes out and the inverter displays "PV Volt Fault". It seems to happen as soon as the batteries are done charging. I've been using this system for about 3 months with no such problem and have not made any recent changes to it. The batteries also indicates "Cell Overvoltage", or that is what I think they are indicating on the LED from what I can gather in manual.

It is Alpha-ESS Smile5 Inverter, 2x Alpha-ESS Smile5 Battery 5.7kWh, and 12x Sharp 330W Poly Solar Panels.

Anyone know what could be causing this?

For now I disconnected the PV and it is working fine off batteries.

Edited August 18, 20205 yr by Leslie

Hi @Leslie

Are your 12 solar panels in a single string?  If so, you may be exceeding the maximum Voc of the MPPT.  The weather is colder at the moment and when the batteries are charged, there may be be a much lower load, resulting in the inverter limiting the MPPT and causing a rise in the PV voltage.  This is worse if the PV cell temperature is cooler and might explain why you are only seeing it now.

My 2 pennies worth.  I'm no expert, so apologies if this sounds simplistic.  Where are you based?  Here in the Cape it's decidedly cooler and I have noticed an increase in my PV voltage, especially when the batteries are full and stop charging.

Yes, it is single string and it has been quite cold since a cold front is comming over. I live in the Karoo in open area with cold winds.

I guess that explains it then, thanks !

 

@Leslie

Just did a rough calculation on your setup and if the ambient temp is about 10 C, then your predicted max PV Voc will be about 580 V, which happens to be the maximum V the ESS Smile will handle. 

The solution, I think, is to split the array into 2 strings (6 panels in series) in parallel.  This will halve the PV voltage, but double the Amperage which will have to be taken into account if you have fuses and cable sizing.