Hi i have a Mecer 8kva unit. It was working well till is started having error F12 DC DC voltage high. It read PV 567 volts with out any PV connected on both Mppts and batter voltage 75 volts with no battery connected . but with AC in only. When PV and battery is connected it shows the same voltages and F12 please hwlp

52 minutes ago, Aubrey said:

It was working well till is started having error F12 DC DC voltage high.

My manual says this fault code means DC-DC over current. If I read the firmware correctly, it happens when the DC-DC current is measured at over 76.5 A for more than 10 ms (1/100th second). I believe that this must be at the bus end of the DC-DC, since 76.5 A at 50 V is only 3.8 kW.

In conjunction with the presumably unexpected readings for PV voltage and battery voltage, it seems to me that many of your Digital Signals Processor's ADC (Analog to Digital Converter) readings are abnormally high. The ADC inputs of these chips is known to be a little on the weak side, but also one input's voltage going higher than the supply rail can  send currents where they ought not to be, causing many ADC results to go crazy. Both of these point to a faulty control card, or possibly some other hardware connecting to the control card.

Sounds like you might need a repair, unfortunately.

I noticed some swollen caps could that be the issue one on the main inverter board and two on the solar charge controller 

See images 

7 hours ago, Aubrey said:

See images 

I only see one image. One of the medium sized capacitors below the main power supply "transformer" (largest yellow rectangle in your photo) does seem swollen. Noise on a power supply could cause all sorts of problems. 

Edited September 10, 20223 yr by Coulomb

Hi All,

Bump on this issue. Was it ever resolved? What was the underlying issue and resolution? Have a family member experiencing the same error but out of the box installation. Looking for possible avenues to explore. Thanks

 

@Aubrey

At a client, I have two Mecer SOL I AX 8M2, 8 kW, inverters in Parallel and we experienced this fault for the first time yesterday during the 4pm load shedding event.

 

I think that I've solved this problem by setting the Maximum Battery Discharge Current on the inverters.

 

On the one inverter it was 30 Amps and on the other it was Disabled, effectively "maximum". I changed them both to 80 Amps, which will allow my client to draw 8 kW. They have had two load shedding events since this problem and no problems.

 

I'll keep you posted if there is a change.