Easun SMG II 3.6 and water heater - needed addidtional load regulator

[zibzib]

I have new Easun SMG II 3.6KP. To inverter i have connected
only 7xPV (NOCT 231V, 2471W) on input, without batteries and 2kW 230V
water heater on output. Program set is "01 SOL".
When I connecting heater i getting warning 15 "PV voltage is too low".

Is any way to work with than heater when PV not working on 100%?

Maybe is on market any automatic regulator which can regulate power of heater when votage of source is under nominal?

Thank you for your help.

 

[Mattb4]

I will attempt to explain why it does not work. Your water heater element is designed such that the resistance creates 2000w worth of heating at 230vAC. It would develop less heating (watts) if run at lower voltage than 230vAC. However your inverter is designed to output 230vAC. It does this by taking watts from the solar panels and converting the DC voltage to AC voltage. So long as there is sufficient PV voltage in the AIO continues to develop 230vAC out. If it can't than it shuts down.

As solar panels are loaded the voltage they can develop drops from Voc downwards. This voltage can reach near nothing if the amount of load exceeds the ability of the panel to sustain load. Just like a discharged battery voltage drops to near nothing. Since your AIO needs a certain incoming DC voltage to operate it will fault if that voltage drops too low and cease developing AC out.

There is no way to overcome having insufficient PV in when loads exceed supply without an additional supply such as battery or other power source like utility.

So you can either reduce loading or increase supply.

 

[zibzib]

So you can either reduce loading or increase supply.

Thanks. I was afraid of this

 

[Larry Oswald]

But if you add a 24V battery the solar will continuously charge you battery and then return energy to intermittently operate the water heater. Your panels are enough to provide 2KW or 50 A to the 24V battery. I assume you do not take continuous showers. Use either the 230VAC or 240VAC output. The batteries may not need to be 100Ahr. Two 12V 50AHr might work. If the water heater calls for power with no or little sun the batteries will deplete and the EASun will shut down after a short while.