Hello everyone,
Yesterday, quite by chance, I watched a YouTube video where someone reviewed their past year with a photovoltaic system and its battery storage. Since I don’t know much about this, and the guy was using exactly the hybrid inverter we are planning to get (KOSTAL PLENTICORE plus), I watched the whole thing.
One detail stood out to me, which he was quite frustrated about because he hadn’t paid attention to it when buying. It was about the maximum charge/discharge current at the battery input. He mentioned that while he made sure the battery itself had a relatively high limit (I think it was 25A), he overlooked the fact that the inverter has only 13A.
I didn’t fully follow his explanation, but he described the problem as the low current limit of the inverter restricting the battery’s output, which means that only about 2.6 kW instead of 5 kW can actually be delivered. This, he said, might lead to situations where if the washing machine and dishwasher run at the same time, grid power would have to be drawn.
This got me thinking, and I searched online for keywords like “what to consider when buying an inverter” and so on. I also skimmed through some forum threads but couldn’t find any advice highlighting this particular specification anywhere.
Am I fundamentally misunderstanding something?
Could someone here explain exactly what this is about? And are there other specs one should pay attention to as well?
I can well imagine that in our case, loads like this will be drawn quite often, and I would be annoyed if such a small detail caused unnecessary grid power consumption.
Best regards
Yesterday, quite by chance, I watched a YouTube video where someone reviewed their past year with a photovoltaic system and its battery storage. Since I don’t know much about this, and the guy was using exactly the hybrid inverter we are planning to get (KOSTAL PLENTICORE plus), I watched the whole thing.
One detail stood out to me, which he was quite frustrated about because he hadn’t paid attention to it when buying. It was about the maximum charge/discharge current at the battery input. He mentioned that while he made sure the battery itself had a relatively high limit (I think it was 25A), he overlooked the fact that the inverter has only 13A.
I didn’t fully follow his explanation, but he described the problem as the low current limit of the inverter restricting the battery’s output, which means that only about 2.6 kW instead of 5 kW can actually be delivered. This, he said, might lead to situations where if the washing machine and dishwasher run at the same time, grid power would have to be drawn.
This got me thinking, and I searched online for keywords like “what to consider when buying an inverter” and so on. I also skimmed through some forum threads but couldn’t find any advice highlighting this particular specification anywhere.
Am I fundamentally misunderstanding something?
Could someone here explain exactly what this is about? And are there other specs one should pay attention to as well?
I can well imagine that in our case, loads like this will be drawn quite often, and I would be annoyed if such a small detail caused unnecessary grid power consumption.
Best regards
RotorMotor schrieb:
As I said, how often do you use your cooktop in P mode?
A few seconds to minutes.
You don’t usually charge an electric car from the home battery.
Same with heat pumps and air conditioning (though they rarely, if ever, need more than 1kW).
Mechanical ventilation with heat recovery, servers, etc. are of course powered by it, since they run at night as well.
But all of that adds up to around 200W.
As I said, a battery system should be designed to cover the base load. It can of course balance peaks occasionally, but it’s not primarily intended for that. You’re right, but (in our case) it happens quite often that two zones run in parallel at 2.1kW each, and then maybe the oven as well... But yes, I didn’t quite realize that, for example, the mechanical ventilation with heat recovery doesn’t use that much power and therefore doesn’t draw much at night.
RotorMotor schrieb:
What kind of battery did he have? I think he had the BYD 5.1.
Could that explain the 2.6kW here?
R
RotorMotor24 Aug 2022 16:07Tolentino schrieb:
I would just be very disappointed because this is not some edge case, but something absolutely everyday. Is this really a practical problem or more of a theoretical, subjective feeling?
Nixwill2 schrieb:
You’re right, but (in our case) it happens quite often that two circuits with 2.1kW run in parallel, maybe even the oven as well... But yes, I wasn’t really aware, for example, that the controlled mechanical ventilation system doesn’t consume that much and at least at night it doesn’t draw a lot. Again, the question is how often and for how long does this actually happen?
And only when there’s no sun?
We also cook a lot and apparently don’t have this problem, otherwise we would have had to buy more electricity.
Nixwill2 schrieb:
I think he has the BYD 5.1.
Could this explain the 2.6kW here? Exactly, that is the smallest one (which we also have) and it can deliver a maximum of 2.6kW.
RotorMotor schrieb:
Exactly, that is the smallest one (which we also have), and it can deliver a maximum of 2.6 kW. But it could deliver more if the inverter allowed more than 13 A, right?
Since I can’t measure the electricity consumption yet, it is still theoretical. But I believe we already have a generally higher base load (compared to some others), and yes, cooking in the evening hours definitely takes place, if not daily, then at least several times a week.
R
RotorMotor24 Aug 2022 16:29Nixwill2 schrieb:
It could deliver more if the inverter allowed more than 13A, right?Correct. The 5.1 model could provide 25A or even 50A for 5 seconds on a different inverter.Tolentino schrieb:
But I think we already have a generally higher base load (compared to some others).That is of course unfortunate. Maybe that’s something that could be improved. If nothing else works, a larger storage system might make sense anyway and would then also deliver more power.
Tolentino schrieb:
Yes, cooking in the evening definitely happens, if not daily then at least several times a week.That’s good in principle. The question here would be how long the hob actually stays in boost mode. For us, it’s usually short, because the water boils very quickly and everything else burns if left in boost.
And then the question is how much power it really draws. Ours, for example, uses 3.2kW.
So at 3 minutes, you would only need about 30Wh or less than 1 cent of additional purchase, right? 😉
RotorMotor schrieb:
If there’s no other option, a larger storage system might make sense anyway, and that would also deliver more power.Or choose an inverter that provides higher output. Is that available, or is Kostal actually quite well positioned here?Are you generally satisfied with your technology? Would you buy something different today? Personally, I don’t know a single brand in this sector; the brands I mentioned are standard with the home builder.