Sunsynk 16kW on a 60A feed

So a while back CoCT saw the light and lifted the restriction on generation capacity. We have a 60A feed and the limit is therefore 13.2kW. My question is how exactly is this limit applied. For example which of the following would be fine if I installed a 16kW Sunsynk:

  1. 8kW panels + 5kW batteries. Actual generation can’t exceed 13kW even though the inverter is rated for 16kW.

  2. 12kW panels + 5kW batteries but software limited to maximum 13kW generation.

PS: I understand feeding back to the grid is limited to 3.5kW but I’m not considering that any time soon.

This is potentially an interesting debate.

Previously (before the limit increase) CoCT considered only the “generation capacity” and not the “ups capacity”. So it would either be limited by the amount of modules or the size of the inverter in total if that was less than the installed PV capacity.

But I note the table is updated to state maximum INVERTER capacity:

And the Hybrid Section makes it clear:

So the problem here is CoCT will be looking at the 16kW and saying, nope you cannot regardless of the panel and battery set up. Your batteries can provide short burst over current. (this can be seen as a reason to them).

I think the only way this could work is if you take option 2, limiting the inverter (by software) to 13.8kVA (I know Sunsynk can do this).

Then it would not matter how many modules and/or batteries you add to the system as the Inverter is limited to the grid connection.

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I think if you want to install the 16kW then you would have to upgrade to an 80A feed.

The CoCT North devision specifically told me they stopped upgrading feeds for “solar reasons”. You first have to demonstrate a legitimate “pull” use case before they’ll do that.

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Asking here instead of a new thread … if the SSEG limit is 3.5kw on 60a, to do that with our current setups, is going to be interesting.

So when we can sell power back, could one install a 3.5kw grid-tied Solis, feedings its max back to the grid earning some bucks whilst the Sunsynk/Victron is set to not feedback anything?

Yeah you will have to extend it.

Yes, you could do that. Or you could use a Fronius/Fimer instead, and use the limit function in Venus-OS to limit the total system feed-in to 3.5kW, which will then also allow feeding in the excess from the DC-coupled Victron side.

Either way, you will have to lodge a new application with CoCT when you modify the system, and whatever new regulations are in play then (remember the fireman’s switch on your outside wall, which is now indefinitely postponed?) will then apply. You have to do this anyway, since you will be switching to an SSEG tariff then.

AND you could have a big array and start feeding in the full 3.5kw earlier and continue later…

@TheTerribleTriplet , there is the answer. You will first have to jump through the hoops unfortunately.

Dankie.

Methinks, the longer and harder electronics work, the shorter their lifespan so my thinking at this point in time is to not use “expensive quality” equipment, instead go for cheaper like Solis with a 10-year warranty, in order to get a quicker ROI, and it is cheaper to replace down the line.

If the sums make sense on the cost of cells and i.e. one can use them harder and they i.e. don’t die of old age, maybe yes. But that goes back to “expensive” equipment working really hard.

Initially, I will use the current setup. In the end though, even that will depend on the “Cost to Me” to be switching to SSEG tariff, new meter, and meeting all the new requirements.

I don’t understand what you’re talking about here. I’m not talking about taking energy from your battery and selling it to the grid. I’m talking about when the batteries get full, and you have “Feed excess DC-coupled PV into the grid” turned on.

Then, when you use a PV-inverter that Venus can control, it can limit the combined system export to a certain value. Which means you don’t have to split the feed into separate systems, and then your PV modules that are DC-coupled become useless when the batteries are full.

Of course, the cost/benefit analysis is left as an exercise for the reader. I fully understand that the Fronius is 2.5 times more expensive :slight_smile: