BryanM

SunSynk 12K Updated - 22 November 2022 Original MCU versions: M 2004-1108 / S 18-07 / C 1001-E024 New MCU versions: M 2004-1123 / S 18-07 / C 1001-E030

Yeah - thanks I did check that and they aren’t connected. As you and I discussed before, I have a Teensy on route and plan to intercept the CAN charge voltage limit message which the PylonTech sends to the Inverter (i.e. 53.2v) and replace it with 52.4v. I’ve seen a post when Victrons have had similar issues, on the Victron you’re able to override the value the BMS sends but unfortunately on the SunSynk not. https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom#:~:text=The%20Pylontech%20battery%20requests%20a%20charge%20voltage%20of%2053.2V Relevant quote from the above link “My system only charges the battery to 52.4V When DVCC is enabled, the battery (via the CAN-bms) is responsible for the charge voltage. The Pylontech battery requests a charge voltage of 53.2V. We have however found that in practice this is too high. The Pylontech battery has 15 cells in series, so 53.2V equates to 3.55V per cell. This is very highly charged and makes the system prone to go overvoltage. It should also be noted that a LiFePO4 cell stores very little additional energy above 3.45V. For this reason we opted to override the BMS and cap the voltage at 52.4V. This sacrifices almost none of the capacity and greatly improves the stability of the system.“

Hi Barry, I’m having the same issue with a 12kw 3 Phase SunSynk and 3 x UP5000 Pylons. I have upgraded the firmware and battery firmware’s and am still having the overvoltage alarms. Let me know when you find out please. Will let you know if I find anything too.

Thanks Tinbum - very concerning read. One thing mentioned in the notice you attached is that I should check if my cable Pins 1/2/3 are NULL (not connected). I'll do that tonight. I might also try a different Battery as the Master

I have a 12kw 3-phase Sunsynk with 3 x UP5000 Pyltontechs - the Sunsynk and Pylontechs are running the latest firmware. I'm currently experiencing an issue where one or two of the Pylontechs will go into an overvoltage error state and stop. I then need to turn off the batteries and restart them to bring them back. The error state seems to occur after my batteries have reached 100% SOC from the sun during the day - this seems to happen at least once a week. I allow my batteries to drain down to 35% over night and then use only the sun to charge them up - they are typically charged by 110h00 to 12h00 in the day and the error tends to happen around 13h00 on the day that it happens. When looking at the Inverter voltage graph - the graph shows a voltage of 55.5V at 12h35 which is around when the alarm started. Screenshots of the Battery Voltage, SOC and Current on the most recent day this happened. The drop off in the SOC and Voltage is where the batteries were turned off and left off before they were turned on again. The system is relatively new inverter and batteries have been in for about 2 months and panels for a month. Has anyone seen this or has advice on what to do to prevent this from happening?

Please, any advise really appreciated here. Looking at the manual for the CHNT External Meter it looks like the meter is installed between the Grid and the Inverter. Based on the image from the manual below, it doesn’t seem to me that the meter can replace the function of the CTs and CTs are still required to control the power fed back into the home and to control the export onto the grid? Has anyone got advise on this and if they were able to replace the standard CTs with a CHNT DTSU666 meter at the main grid connection for your house. Or are the CTs always required for the SunSynk to work effectively in a grid-tied environment? My application is that I have various DB boards and need to measure the overall load from the grid connection point which some distance away from the inverter (30m+). So would like to use the CHNT Meter at my grid metering point for best accuracy rather than CTs with 30m long cables.