I am looking to upgrade my system to a Sunsync 5kw inverter system. I reside in Cape Town and now with the new laws kicking in from the 1 Oct 2023, I need to change my inverter to something that is is on the approved list. I currently have a  FiveStar inverter 3.5kw inverter connected to 4x 100ah gel batteries. My aim is to run the house during the day from solar and grid (if the power is insufficient) and only use the batteries mainly during load shedding at night. My load during the day is around 400watts per hour and goes upto 3000 watt when using a microwave or kettle. I plan to initially install 4x 545 watt solar panels due to budget constraints.

 

Please advise:

1.  If the Sunsync 5kw inverter is able to meet this requirement by configuring settings to supply power to the household from solar and grid during the day and if i can set the switch back to solar/grid from battery while the battery voltage is relatively high so that i don't cycle the gel batteries during the day as it needs to be relatively full for a loadshedding slot. 

 

2. If the solar panels are installed by a PVGreen card technician, does an engineer still need to sign off the solar installation if I am not planning on feeding back to the grid. However, I will still be using the grid to supply when solar is insufficient.  

Yes the Sunsynk will be able to do all of that - it has a number of work modes that you can tweak as you like 

I'm not sure about the second item though - you'd have to ask other CPT based installers / users who ahve gone through the process

Thank you very much for the feedback. Much appreciated. 

 

2. If the solar panels are installed by a PVGreen card technician, does an engineer still need to sign off the solar installation if I am not planning on feeding back to the grid. However, I will still be using the grid to supply when solar is insufficient.  

Yes, engineer still required, the sunsync is grid-tied, irrespective of whether or not you feed back into the grid.

 

Yes, engineer still required, the sunsync is grid-tied, irrespective of whether or not you feed back into the grid.

The engineer needs to check that all is done correctly and becomes the responsible person for the installation. 

Also quick one the 4 panels will be too low on the voltage side and low voltage causes havoc and blows MPPTs, they say 5 is the minimum but 6 is actually the best as minimum to make sure the voltage is enough. Keith speaks at least spoke a lot about the voltage issues with the MPPTs being too low

Thank you all for the feedback and thanks Dylboy for the info on the minimum amount of panels that should be installed. i was previously advised that a minimum of 4 panels should be suffice.

Wrt a PV combiner box, most are rated 600v for use in a 5kw inverter and 1000v for use in a 8/12 kw inverter. However, the MPPT charge controller max voltage on a Sunsync is 500v.  Wont a 600v rated combiner box be too high to offer any protection ?