LuxPower - emergency backup enabling

[Joeboy]

I have been thinking about that suggestion, more as an emergency backup, but with that DC-AC portable inverter , that looks like it only goes to 48V , wont the DC input from the PV string be much higher than that? or do you just have a few panels connected?

So am I basically screwed with what I have? (Growatt min 6000 with PV + Luxpower ACS 3600 with batteries)

In an extended power-cut I can run the UPS load until the battery expires and then everything is off.

Is there a solution that will let me keep the batteries, PV and preferably the inverters, or do I need a different solution to work in an extended power cut?

Steve,
My solution to grid loss and keeping access to the DC power in the batteries is a DC to AC inverter with 3 pin plug built in, T'd off of the battery stack. Its not particularly fancy or expensive and it is simple although i am restricted to an extension reel to where i need the power. I also have the benefit of half the PV running through a charge controller directly to the batteries rather than through a grid tied inverter. The result is an offgrid reliable 2kW supply that can spike to 3kW for short moments fed from 5kWp.

Something like this.
https://www.amazon.co.uk/FENGSSLL-Effic ... 02&sr=8-18

Basic though this solution is I can cook, heat my HWT, run PC, TV, lights etc if the grid fails. Although not all at once! I have run the washing machine on the inverter as a test, no problem. I could also charge the EV through the granny charger. My point being that for not too much outlay a reasonable facsimile of normal life can take place in extended power outages. Preferably in the March to Sept window.

Fair point, there are so many different system combinations out there. Just being generic, irrespective of how many panels and inverters or solar controllers are in a systems design eventually that power potentially flipped multiples times through AC & DC will eventually end up as a 48V DC stored energy bank (could be 12V or 24V as well, system design depending). I then T in an inverter to the positive and negative side of the battery bank et voila 230V AC on a socket offgird. I hope that makes sense?

One of the best ideas I find, is to do a line diagram. Just get a sheet of A4 and a pencil. Get your head round what you've got and then extend it into what you want to have. It's a brilliant shortcut.

[Stinsy]

I have been thinking about that suggestion, more as an emergency backup, but with that DC-AC portable inverter , that looks like it only goes to 48V , wont the DC input from the PV string be much higher than that? or do you just have a few panels connected?

Sure string Voltage will be much higher than 48V, there is a charge controller sat between the panels and the batteries that converts string voltage into 48V.

[Kommando]

Found out that the Solax X1 Boost G3, which is a cheap and freely available new G98 inverter, can be made to control its output via the connected Grid frequency.

https://community.victronenergy.com/que ... erter.html

The two parameters that need adjusting are

FreqSetPoint (Htz)

and

FreqDropRate (%)

So for a Sunny Island these would be set to 51Htz and 10% so that by 52Htz the output is zero.

You also have to set the Grid country to one that supports these parameters, eg EN50438_NL, VDE4105 or User Defined

and also play around with parameters to improve stability

Fac Upper and Fac Upper slow

These parameters are also on the G4 version but hidden a bit further down within Grid Services.

[Kommando]

Well I have this up and running on an Solax X1 Boost Gen 3 but the settings given to me by Solax support were wrong. To match the SI frequency shifting the settings are

FreqSetPoint (htz) 51

FreqDropRate (%) 2

I tried the suggested 10% given by Solax support but the Solax X1 dropped its production as the frequency increased but was still making power at 52htz, so the SI increased the freq over 52 htz until the Solax then disconnected with grid fault. Went back to Solax support and they eventually worked out their initial info was wrong and gave me a revised setting of 2%.

The formula is (End freq-start freq)/nominal freq as a %

so (52-51)/50 = 0.02 o= 2%