Victron MultiPlus-II inverter & charger - dc coupled and grid tie

yakapo7

Assuming I have a Victron mppt controller, and a 48v battery, can this inverter feed power to the grid? 

Is it limited to 3,000 watts?  

BB.

This inverter?

https://www.solar-electric.com/victron-multiplus-ii-inverter-charger-48-3000-35-50-120vac.html

The manual seems to indicate that it is possible:

https://www.solar-electric.com/lib/wind-sun/Manual-MultiPlus-II-48-3000-120-35-50-120V.pdf

2.4. ESS – Energy Storage Systems: feeding energy back into the grid

When the MultiPlus-II is used in a configuration in which it will feed back energy into the grid it is required to enable grid code compliance by selecting the appropriate grid code country setting with the VEConfigure tool.

Once set, a password will be required to disable grid code compliance or change grid code related parameters.

Depending on the grid code there are several reactive Power control modes:
 • Fixed cos φ
 • Cos φ as function of P
 • Fixed Q
 • Q as function of input voltage

Can the unit feed 3,000 Watts back into the grid? I am guessing not... On page 25 (pdf page 28) it has a disclaimer:

Cont. output power at 25°C (3) 3000 VA
Cont. output power at 25°C 2400 W
...
3. Non-linear load, crest factor 3:1

It appears that the unit is rated for 2,400 Watts continuous output... And will run 3,000 VA (Volt*Amps) into non-linear loads (induction motors, AC input power supplies, etc.)--Basically 2,400 Watts is maximum power (into "perfect" resistive loads) and 3,000 VA into less than perfect loads (induction motors, etc.). V*A can be higher than Watts when the loads pull current out of phase with AC voltage (induction motors) or pull peak current at the voltage peak (diode+capacitor input to many, especially older, power supplies for computers, LED/Fluorescent lights, etc.).

Pretty much by definition, the "Utility Grid" is a "perfect load"... And in any case, you can have a power limit of 2,400 Watts (actual "power" fed into the grid (or loads), and 3,000 VA both be true at the same time (i.e, running an induction motor). "Watts" (actually kWatt*Hours) is what you "pay for". VA is what you size wiring, transformers, and inverters for (more or less). Some inverters have Watts=VA as a limit, and others can be rated for Watts<VA (better supply "poor" PF loads). As far as Batteries (and solar panels) are concerned--They only "see" the Watts. VA is only (mostly) on the AC output side of the inverter.

The ratio of Watts/VA is also known as Power Factor (PF=1.0 is "perfect" power factor; PF=0.5 is pretty poor PF--Seen on inexpensive twisty florescent bulbs and such).

https://en.wikipedia.org/wiki/Power_factor

How to program the Victron for GT operation--I have no idea (reading more manuals, getting configuration software, etc.)...

Helpful?

-Bill

yakapo7

Yes, thank you. 

How is this different than a hybrid inverter?  It doesn’t have a controller and it requires a battery.  Is that all? 

BB.

I use "Hybrid Inverter" around here to (generally) indicate an Off Grid + Grid Tied capable inverter. So, by that definition, the Victron is a Hybrid Inverter.

The OG part usually needs a battery bank to provide power when the sun (and/or grid) is down... Place to store energy. Add a genset (+fuel--another stored energy source) and definitions become "more complex".

And you have the OG capable inverters that do not have (or possibly can operate off grid) without a battery. SMA has their Secure Power units (no battery possible--An "over-sized" solar array provides more than enough power to supply a limited capability 120 VAC circuit). And other OG (and GT capable) inverters that the battery bank is Optional (I think Must power company has/did have models capable of running with or without a battery bank).

The reality of inverters, inverter-chargers, OG and GT inverter, generator support, inverter-generators, etc... It gets really difficult to pigeon hole a large group of "inverters/black boxes" into a specific class/group/place holder.

For me--It really does come down to asking what the poster/owner needs (wants) and see if there are one or more\ "black boxes" that are capable of performing that function (and be cost effective).

Since I am not in the business--I can give you the 50,000 foot view (i.e., from a high flying plane) of how to address the questions. Others here have much more knowledge and experience than I--Sometimes in very specific applications that can help with much more detail than I--And always finding a detailed manual/set of specifications, is where we have to end up. BEFORE BUYING ANY HARDWARE.

-Bill

yakapo7

I’ve built a small solar generator using a Victron controller.  Now I’m looking for a larger scale solution.  There are no installers who have done ac coupled systems in my area (Dallas TX.  If I’m going through the trouble of putting panels on roof, it seems like I should get more than just 2.5kw (the limit of what the Victron can supply the grid).  

I think I’m going to have my buddy install the solar edge pv inverter with 5kw of panels on the roof and then use this Victron inverter ac coupled with the solaredge.