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amrod avatar image
amrod asked

Lost in inverter functions. Which to choose?

Hello community!

I'm trying to find out how to set up the small hybrid solar installation in my vacation house. I love the flexibility of Victron, but on the other hand I am worried I'll miss, that some functionality is not supported by the inverter/charger I'll choose.

What I want to build:

- solar installation on DC side

- charging 48v ~10kWh LiFePo4 battery

- 4-6kW inverter

System is sized to power the whole house during the summer season and in winter when we are not using it (standby mode, only basic devices and running pumps of central heating)

How I want it to work:

- I'd like it to power the house form battery for as long as possible (keeping battery health in mind, so probably not lower than say 25% SoC) and if its not enough to use only off-peak grid power

- charge battery from the sun

- if excess sun power available - dump it to heat the water

- if battery SoC below certain low level - charge it from the grid to the set level, but only in off-peak tariff (time constrained)

- if grid unavailable, switch to off-grid with anti-islanding in mind - requirements of Polish network to be fulfilled.

What is my question:

The question is if I am able to set all I pointed above to be executed by one of the inverters listed below?

  1. Multiplus II 48/5000/70-50
  2. Quattro 48/5000/70*
  3. Quattro II 48/5000/70*
  4. Multi Solar RS
  5. Easy Solar 5kva

If by more than one of them - what's the difference I should care about?

Multiplus-IIMultiPlus Quattro Inverter ChargerESSEasySolar All-in-One
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2 Answers
marekp avatar image
marekp answered ·

@Amrod

It can be done.

You have to decide how much power you need from this system.

4 to 6kW is a big swing.

The units you are asking about are 5000VA not 5000W.

5000VA will cover constant power requirements closer to 4kW than 6kW.

If you do not have gas generator Quattro is not needed. MultiPlus-II will do.

Even if you are planning to use generator it can charge batteries directly so the second AC-in is not needed.

EasySolar 5k would also do the job, but based on my own experience I suggest to go with separate components.

MultiPlus-II/5k

Cerbo GX

MPPT 250/100

It will cost slightly more but in case something fails you do not have to replace the whole thing and you can chose components that better do the job.

There is only one advantage of ES unit. Not much wiring required.

The rest of your needs can be done by programing (ESS assistant and scheduled charging)

The MP-II unit has the anty-islandig build in but I am not sure if it is certified in Poland (I heard conflicting reports), but if you are not planing to back feed excess energy to grid you do not have to report your system to authorities.

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Mike Dorsett avatar image
Mike Dorsett answered ·

all of the inverters will cope with the main aim, by selecting ignore ac in. This will stop grid charging as long as the battery is above a set SOC. The will also operate in off grid mode with no problem.

Charging the battery from the sun is default with an MPPT charger.

The more complex items like dumping excess power and charging at off peak times need to be implemented with external control code, eg node red.

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