The SG15RT complies with VDE-AR-N 4105 and therefore supports Frequency-Watt — in other words, reducing PV output when the battery is full.
Is anyone running such a setup and able to confirm that the output can be throttled down to 0?
Victron expects 0 power at 52.7 Hz.
Could you please describe your system and where you intend to use Sungrow?
The Sungrow is connected to the Victron’s AC. It needs to be controllable via frequency shifting when the battery is full.
Inverters with 4105 manufactured after 2011 must reduce their power output as the frequency increases. The country code often includes something like :2011 or :2018. However, according to 4105, the minimum is reached at 51.6 Hz; at 51.7 Hz, the inverter should disconnect.
And which MP II?? The 1:1 rule must also be observed!!
Hi Norbert,
give us a little more information, please…
Off-grid, on-grid, ESS
AC out – AC in…
A diagram would also be much appreciated
Victron is a manufacturer of several hundred products, so you’ll need to be a bit more specific when describing your components.
Planning: 3 MultiPlus 5000s, 2 Pytes V5s.
ESS, on-grid; since it’s three-phase, after the meter it goes into AC in and then from AC out to the house distribution board (without any changes).
This means the Sungrow is connected to AC out.
It’s specifically about frequency control and whether the Victrons can potentially regulate the Sungrow down to 0 in emergency operation.
The Victron apparently has an upper limit of 52.7 Hz — at that point, the Sungrow must no longer supply anything!
Can the Sungrow do exactly the same?
Does anyone have this exact installation?
The two Pytes batteries appear to be too small for the system. In addition to the charging and discharging power, the Factor 1 rule must also be taken into account.
You can see how far the MultiPlus can increase the frequency in Demo mode using the Fake Device in Ve.configure.
You should find the remaining values in your solar inverter’s documentation.
Good luck
The MP2 throttles the inverters. According to observations, it also does this when operating in island mode and the grid returns after a simulated power cut. It can then take up to 15 minutes for the inverters to ramp back up to full output.
That much is clear!
The question is, “whether Sungrow will accept it, and how?”
Hello @NorbertKr,
apparently, no one has any experience with this particular Sungrow.
Neither do I.
Under specification AR-N-4105, it must be controllable; otherwise, it would not be permitted to operate on the German/European grid.
Victron uses Frequency-Watt for off-grid operation, and it can even be configured with VeConfigure.
I have Hoymiles connected to ACout. It works.
How it works: the MP2s increase the frequency, according to the frequency. Conversely, the power must be reduced by up to 60% in a linear relationship with the increase in frequency. The system then shuts down.
When the frequency is reduced (Recovery Frequency), the inverter switches back on after checking the grid (MP2 island grid). The Ramp Rate defines how quickly the power can be ramped up again.
The additional information about your system design concerns Victron’s requirements for making it work. If you do not observe the important design rules, your system could catch fire because the energy cannot be absorbed during the changeover period.
So, in short:
We don’t know; it should work according to the approval.
Your system has not been designed safely—dangerous!
Here are the Hoymiles grid code parameters:
… your statements:
I understand factor 1, but how do you arrive at a factor of 3–4 for the storage capacity?
If the inverters each draw 5 kW (15 kW in total) according to the factor-1 rule, should the battery storage be 45 kWh? Why?
When the battery is full, the MP2s throttle the Sungrow anyway — even with 10 kWh.
Greenakku sells the MP2 48v 5000 set in a three-phase system as a 15–30 kWh storage system, which can be expanded modularly.
I would have to consume electricity for 2 hours at full load (12 kW continuous output) to run it flat. The Liontron batteries are specified as having ideal charge/discharge currents of 0.2–0.5C. 100 Ah = 20–50 A. At 12 kW, the discharge current would be 250 A, i.e. a maximum of 50 A per battery.
Hallo @NorbertKr
die Ausführungen von @BjoernK mal im Detail:
Bei Pytes ist die Doku ein wenig dünn, daher nehme ich meisten die Werte von Pylontech und rechne die auf die anderen Batteriehersteller um.
Für Pylontech wird PRO Mp2/5000 100A = 300A Mindeststrom empfohlen
Die Pytes V5 haben 75A sprich für die 300A mindest 4 Blöcke
These minimum battery sizings are required for reliable operation.
An example of minimum system sizing based on the US2000 battery module is below. Each battery module is approximately 50Ah at 48V, can provide 25A continuous charge and discharge and 100A peak for 1 minute.
| Inverter / Charger Model | Inv continuous watts @ 25 degrees | Inverter peak watts surge rating | Number of Pylontech modules | Battery continuous discharge watt rating | Battery peak discharge watt rating |
|---|---|---|---|---|---|
| Multiplus 48/500/6 | 430 | 900 | 1 | 1200 | 4800 |
| Multiplus 48/800/9 | 700 | 1600 | 1 | 1200 | 4800 |
| Multiplus 48/1200/13 | 1000 | 2400 | 1 | 1200 | 4800 |
| Multiplus 48/3000/35 | 2400 | 6000 | 2 | 2400 | 9600 |
| Multiplus 48/5000/70 | 4000 | 10000 | 4 | 4800 | 19200 |
| Quattro 48/8000/110-100/100 | 6500 | 16000 | 6 | 7200 | 28800 |
| Quattro 48/10000/140-100/100 | 8000 | 20000 | 7 | 8400 | 33600 |
| Quattro 48/15000/200-100/100 | 12000 | 25000 | 10 | 12000 | 48000 |
Weiter geht es mit dem AC coupling
Besides the relation between installed PV Power and the inverter/charger VA rating, it is also important to have a sufficiently sized battery. The minimum battery capacity depends on the type of battery, lead or lithium.
Note that, besides the minimum battery capacity, the mentioned sizes are often also the most economical battery size. In case used for self-consumption purposes that is. In case the goal is to increase autonomy, of course installing a large battery increases the system autonomy in case of a grid failure.
3.2 Lithium batteries
1,5 kWp installed AC PV power requires 4.8 kWh of battery storage:
** 100 Ah at 48 Vdc**
Each additional 1.5 kWp of AC PV will require an additional proportional 4.8 kWh increase in battery storage.
Ich komme auf auf über 8 Batterieblöcke für die 12,5 KW AC PV
„ 3.2 Lithium batteries
1.5 kWp of installed AC PV power requires 4.8 kWh of battery storage:“
If the battery is at 100% SOC, the Sungrow is generating power and then the grid fails, the energy must be absorbed at short notice.
This frequency control is an emergency curtailment measure for AC-WR—in case the European interconnected grid ever collapses.
Whether it would all really work as planned is another question.
But designing a system to regulate itself internally in the event of very rare power outages…
That would require a lot of testing and simulations.
I’d steer clear of something like that—especially when you need it, it’ll probably turn out not to work after all.
Are you really so afraid of the apocalypse?
There’s no need to fear the end of the world.
It’s enough for a lorry to take out a medium-voltage power pole. That’s already happened here in town, and the power went out.
If it happens in summer and the batteries are fully charged, the curtailment is supposed to prevent the voltage from rising too high.
And why keep your fingers out of it? Because it doesn’t work anyway? It does; that’s the required standard.
So please stick to the facts.
I’ll keep this factual — but unfortunately, most people simply have no idea about it.
I work extensively with UPS systems at large events.
A power cut — one that only occurs once every five years or so — means that even quickly installing three MP2-5000s simply isn’t enough; there is much more to consider.
There are some very unusual scenarios — whether it’s switch-mode power supplies with high inrush currents, devices that can’t tolerate the 20 ms switchover time, loss of internet connectivity, and so on.
Simply installing three MP2s and thinking you’ve bought yourself absolute security is nowhere near enough.
At these events, we deliberately don’t use Victron as a UPS, even though it’s an excellent system.
It isn’t suitable for that purpose — but that also stems from it having been designed for a different use case.
But this is also comparing apples and oranges.
If I need a UPS for a large-scale event, then we’re talking about entirely different dimensions.
And in that case, I go straight for autonomy for the transmission equipment. I don’t want a glitch with the link going down for 4 seconds while the frame is rebuilt (MPEG-4).
For a private household, the MP 2-XXXX units are sufficient. And the issue here was whether I can use the frequency to curtail µWR at the AC output or not.
No, this wasn’t about data centres, concerts or other large-scale events.
The question was simply: Will my system burn out, or potentially not…
And ignoring that essentially means, in the worst-case scenario: battery BANG
