Hi All

I was planning to get installed a 5kw Sunsynk inverter, 5.5kw hubble battery and 12 x 455w. My question is what benefit would it be if i were to install a 8kw sunsynk inverter and the rest of the package remaining the same.

Hey @taahir1981, the benefits are quite simple. With an additional 3kW of capacity, you can support a larger load. My friend has an 8kW ESS and he can boil the kettle and run the rest of his home without having to disconnect certain high current appliances. Things with a coil or element need a lot of current, most 5kW inverters use their entire capacity running lights, PCs, internet and all the usual odds and ends but boiling a kettle as well can be a little too much.

Its more of a safety and re-assurance thing, you are unlikely to hit the inverters max unless you're using geysers etc at the same time. Plus, having an inverter operate at under 50% usually leads to better efficiency. If you want more solar power, the 8kW will likely have a bigger MPPT. It's more about future proofing, if you have the money and want to be completely uninvolved with managing the system then go bigger. If you would rather spend a little less and take a minute or two to check load levels etc, the 5kW is probably the better choice.

Be careful of Hubble, they are problematic. My Hubble loses 1% everyday

21 minutes ago, Nick2020 said:

Be careful of Hubble, they are problematic. My Hubble loses 1% everyday

Get a firmware update to fix the hubble problem.
See https://powerforum.co.za/topic/11206-hubble-lithium-battery-am-2-55kwh/

In terms of 5kW vs 8kW, it depends if you have split the DB into essential (UPS) and non essential loads.
The inverter is able to provide power to loads on the grid side of the inverter (reverse feed).
If you've split your DB, with stove, geyser, dishwasher, tumble-dryer on the grid side,
a smaller inverter will do and the inverter will provide excess power to these grid side appliances.

In my case I have an 8kW inverter and my DB board is not split.
The whole house is on the UPS side of the 8kW inverter.
This works well with no trips.
If grid is on, you can support more than 8kW load.


10kW UPS Load ~ 4.9kW from Solar PV + 3.5kW from battery + 2.0kW from Grid
The numbers don't add up exactly as there is some lag in SA, but close enough.
The inverter is inverting ~8.4kW

I have installed some home automation to switch off geysers, dishwasher, washing machine, stove when battery falls below 20%.

Edited January 10, 20232 yr by system32

If you only want to run plugs and lights 5kVA will work.  If you want a Geyser operational, then 8kVA may be the best option for rainy days.

My loads are very light at night (.25kw as a max) and with 15kW of batteries, I will be moving my Geyser onto the Solar side, with my Geyserwise set up to heat up between 3am and 5am

My SOC never gets below 70%, so there is a lot available there.