Inverter, what should be considered?

Hello everyone,

Yesterday I accidentally watched a video on YouTube in which someone broke down and explained his last year with his photovoltaic system and its battery storage. Since I have very little knowledge and the guy was using exactly our planned inverter (KOSTAL Hybrid Inverter PLENTICORE plus), I watched it all the way through.

One detail caught my attention that he was very upset about because he hadn’t paid attention to it when buying. It was about the max. charge/discharge current at the battery input. He was annoyed because he had made sure the storage had a fairly high value (I think it was 25A), but he hadn’t considered that the inverter only has 13A.

Although I couldn’t fully follow his argument, he described the problem as follows: due to the low current of the inverter, that of the storage is limited as well, which means that only 2.6kW instead of 5kW can actually be delivered. This, in turn, means it’s possible that if the washing machine and, for example, the dishwasher run simultaneously, grid power might be drawn.

That made me ponder a bit, and I searched online using keywords like “What to look for when buying an inverter?” etc. I skimmed through some threads here and elsewhere but have to say I didn’t find any tip pointing to this specification.

Have I fundamentally misunderstood something?

Can someone explain exactly what this is about? Also, what else one should perhaps pay attention to...

I can quite imagine that in our case this kind of power demand will happen more often and I would be annoyed if grid power were unnecessarily drawn because of such a minor detail.

Best regards

I also have exactly this inverter. The 2.6kW is more than enough for me. You only reasonably have a storage system for the night anyway; I rarely, if ever, exceed 0.4kW then. Washing machines, etc., are run during the day with photovoltaics. Things you can/should wish for in an inverter are rather: noise level (depending on location), emergency power capability (depending on fear of outages), efficiency, logging capabilities, combination with wallbox, support, etc. ;-)

But 2.6 kW isn’t even enough for an induction stove on level P?! Seriously, are the common inverters only capable of that much?

But 2.6 kW is not even enough for an induction stove at level P?! Seriously, are the common inverters really only capable of that much?

First of all, a correction: The Plenticore Plus can do up to 6.5 kW with a large battery.
I just have the "small" 5.1 kWh, because it is simply sufficient and it has "only" 2666 W discharge power.

Basically, it doesn't make sense to size an inverter or the battery for 60 seconds a day.
Better for 12 hours at night.
In the last 5 months, I bought 10 kWh, so a maximum of 3€.
Having a bigger, different inverter and/or storage simply doesn't make sense.
Although yesterday evening around 6 pm, while cooking, 2 kW still came from the roof and 2 kW from the storage, so it's only a "problem" if you cook very late, with very high power. ;-)

I also have exactly this inverter. The 2.6kW is more than enough for me. You only reasonably have a storage for the night anyway, I rarely if ever go over 0.4kW then. Washing machine, etc. is run during the day with photovoltaics. Things you can/should wish for in an inverter are rather: noise level (depending on location), emergency power capability (depending on fear of outages), efficiency, logging options, combination with wallbox, support, etc. ;-)

If even you say it’s enough, there will hardly be anything better (you are already very active in this area here and seem knowledgeable). So does the Kostal score in the other points you mentioned? I have to say I find that rather little. Usually we eat dinner late, which is why Tolentino’s comment makes me even more aware. I already realize, you have to try to change and “program” habits. We both always work long, which is why all major consumers usually run in the evening/night... Cheers to programmable dishwashers and washing machines, the new ones will be able to do all that...

First of all a correction: The Plenticore Plus can handle up to 6.5kW with a large battery.
I just have the "small" 5.1kWh one, because that's simply enough, and it has "only" 2666W discharge power.

That's exactly the point, the calculation in the video was precisely with this inverter, actually 6.5kW, but at 13A. And he somehow meant that this is where the catch lies.
Could the 200V voltage of the battery have something to do with it?