Inverter shutting down due to High Voltage

[troggy01]

I need to run my koi pond by solar but my inverter keeps tripping out due to over voltage? The system was running fine until we got a sunny day about a week ago and ever since the inverter has been causing me nightmares. As you will understand because it is running a Koi pond pump, aerator and a UV light I can't afford for it to keep tripping out. The power consumption is averaging 330 Watts.
The system is as follows

720 Watt Solar panels (6 x 120 watt panels)
EPEVER 30 watt MPPT SCC
1500 Watt Pure Sine Inverter (24 volt)
Transfer switch
200AH LifeP04 Lithium batteries (2 x 100AH paired)

Any suggestions would be greatly appreciated and thanks in advance.

• Solar Charge Controller.jpg
  Solar setup.jpg
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[Ampster]

How are your panels wired, series or parallel?. What is their open circuit voltage? Is it your inverter or Epever SCC that is tripping out with over voltage? The Epever has a maximum voltage of 100 volts.

[troggy01]

Hi Ampster. They are in parallel and it was the inverter that was tripping out. i have ordered a new inverter and changing my SCC to a Victron as this was advised as you have more control with the Bluetooth systems enabled or so I hope. The guy had been having the same problem and went down the earlier route and so far no issues. It was explained that when the batteries were at full charge they can kick out a 31.5 volts spike and that triggers the failsafe but I need it to be stable as it runs my Koi pond I need stability as I can't be watching it all the time. If it doesn't work I will probably post again for help from all the knowledgeable people on here. Thanks for looking at my issue mate.

[Ampster]

Are those AGMs or some Lithium chemistry? They only kick out the voltage that they have been charged to. Typically they also settle after charging. What are your charge controller settings? 31.5 volts seems high for many nominal 24 volt chemistries.

[troggy01]

Hi again Ampster. They are LifeP04 Lithium batteries. They were showing to be outputting around 29 volts but the responder said that he had followed numerous courses to resolve the issue and it was a known occurrence that they spike when reaching full capacity. I will look into setting the system up with Victron SC and fingers crossed I can cure the problem. Thanks again for responding.

[Ampster]

Hi again Ampster. They are LifeP04 Lithium batteries. They were showing to be outputting around 29 volts

If they are LFP batteries in a typical nominal 24 volt system then they are likely eight cells in series.bin that case 29.5 is 3.68 volts per cell which definitely will trigger a high voltage error. Usually they settle to a voltage of 3.3 or 3.4 volts per cell which is 26.4 or 27.2 volts on the pack. They must have been charging when you saw the pack at 29 volts. My suggestion is to use 28 volts as your charge setting to avoid over voltage. There is not much capacity between 28 volts and 29 volts.

[troggy01]

Thanks Ampster. Suggestions taken onboard and I have installed a Victron SCC today alongside a 2000 watt inverter so hopefully it will soon be sorted. I will give it a couple of days to settle down and then if still an issue I will adjust the settings to your suggested parameters. Thanks again for your help.

[Ampster]

....... I will give it a couple of days to settle down and then if still an issue I will adjust the settings to your suggested parameters.

Since you will have to setup the new system I would start with setting charging voltage below 28 volts (3.50 V per cell). My preference is 3.45 volts per cell since there is not much capacity above that anyway.