Morning! We have 2x Kodaks 5kva inverters, 4x US3000 Pylontechs and 24 panels. I was contemplating buying another UP5000 to add to my current parallel setup. I'm a little worried that it just means more charging from Eskom when it's available to top-up all the batteries and whether it's worth it or adding more panels would make more sense. With the unpredictable loadshedding I've changed inverters to run Solar, Utility and then Battery. Any advise? Thanks, Jay

Very seasonal thing ... in summer I need more battery, in winter I need more PV.  What is driving your decision? The onbjective is not clear from your post.

With @Scubadudeon this one... It does very much depend on where the system is currently falling short and what you are trying to achieve.

If you are looking for a general all purpose reasoning, I would tend towards panels. More supplementary power is always helpful, unless you are already meeting your peek energy needs/max panel limit for the unit. Same goes for battery charging etc, if your current panels are enough to power your grid and fully charge the batteries without grid assistance then more panels would be a waste.

1 hour ago, Jeroen said:

Any advise?

Agree with the others. We need a bit more details.

Do your Pylons last you through the night? In summer, around what time are your batteries fully charged again? And in winter? Are your afternoon/early evening loads high, so that you need to start using batteries before the sun has set?

Additional panels will help you in winter (assuming that you currently struggle to fully charge your batteries) - but in summer will be a waste. More batteries always help (not having to cycle you full pack down so deep, extending life of your whole pack), but in winter you will struggle to fully charge them.

1 hour ago, Jeroen said:

We have 2x Kodaks 5kva inverters, 4x US3000 Pylontechs and 24 panels. I was contemplating buying another UP5000 to add to my current parallel setup.

Just beware that I don't think that you can mix your US3000 with the UP5000

Just extrapolating from the little bit of info available. Rough thumbsucks, need more details.

You've got 24 panels, let's assume around 400W each at around 40V operating voltage, whatever it is, and you're probably close to the limit of panels that your existing inverters can take, possibly both in terms of input voltage and power output. You would most likely have to add another inverter in parallel if you went the route of adding panels.

Just, then the inverter and panel capacity would be running well ahead of the charge/discharge capability of your 4x3.5kWh bank of Pylontechs.

Just looking at "balancing" the system of around 10kW of inverter and panel capacity with the 14kWh of storage, it seems you have more "room" for additional batteries to take better advantage of the existing capacity of solar.

But it all depends on your actual power needs and how intend to manage the system. Like now if you're running SUB configuration, and 14kWh is about enough to see you through 2 hours of loadshedding at night, then additional batteries are not going to bring you any benefit.

Similarly, if you add another inverter and more solar panels, firstly you won't be able to increase the power delivery during loadshedding because the batteries will remain your bottleneck, and secondly it's likely that once your batteries are charged, which won't take terribly long, the system will scale back to your daytime baseload demand anyway, it'll just do it sooner.

Without knowing more details about your current system and actual usage, it's quite possible either way from here to spend lots of money for little to no benefit.

10 minutes ago, GreenFields said:

it's quite possible either way from here to spend lots of money for little to no benefit.

The constant battle between the upgrade itch and sanity/reasoning 😜

My YTD grid consumption is around 700kWh (vs a bit over 13,000kWh total YTD load). More than 50% of those 700kWh result from the 3 winter months Jun-Aug. While the itch is constantly there to add more panels (eliminate winter months grid usage) or add another battery (get away from the small now-and-then grid usage early mornings after the kids played lots of PS5 the night before), the financial investment for either one of these options would be more than R20k. And with my YTD grid usage, the payback period is simply too long for that to make any sense.

So sanity prevails (for the time being) 🙃

These are sums of diminishing returns. For example, I would like to run three aircons similtaneously. During the day I need more panels, at night more battery. Then my wife screws it up .. she switches the oven on, now I need a bigger inverter.

So, for the moment we make do with what we have.