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Wessel Wessels avatar image
Wessel Wessels asked

Quattro 48/15,000 Max AC Out

We studied the manuals and spoke to our in country distributors in South Africa and we are getting conflicting messages and need to get to the bottom of this.

We in the process of implementing 2 x Quattro 48/15000 in parallel per phase i.e. 6 in total. Reading the manual it states that if the AC voltage on AC-in-1 or AC-in-2 is switched through, but the load demands more current than the mains can supply, the inverter will be switched on to supply additional current.

Which refers to the PowerAssist where the Quattro can together with a maximum input current of 100A + 65A from the inverter give us 165A (15kVA model) or in our case parallel connected Victrons, we will get 330 Amps per phase (2 x 100a AC Input + 2 x 65A Inverter).

What we can't get a definite answer on, is if this is just for a "rush-in" situation or can it be for a longer period, as we do have sometimes on this site more than a 200A requirement for periods of one hour.

The one solution is we can purchase another 3 Victrons, one per phase but for the short periods it will be in use it is not worth it.


Looking forward to your response.

MultiPlus Quattro Inverter Chargerbattery charging3 phasepowerassist
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boekel avatar image boekel ♦ commented ·

But...these kind of systems should be handled by experienced people, the numbers you talk about are serious stuff. The questions you ask lack information to be answered.

Let's start with what kind of system are you designing:

-what (if any) grid supply is available?
-what is the required power you need to maintain when the grid fails?
-PV system?
-Generator?


If you have 6x 15k unit, at full continuous power, you are talking about 2000 - 2400 A current at 48 volt, that's a BIG battery that needs well trained engineers / installers.

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4 Answers
Johannes Boonstra (Victron Energy Staff) avatar image
Johannes Boonstra (Victron Energy Staff) answered ·

Hello, PowerAssist/Suplementing power to the incoming AC can be as long as there is demand (and enough DC capacity of course). For the inverter is doesn't matter if it delivers the maximal inverter power in inverter mode or in PowerAssist mode. Limiting factor is ambient temperature and DC energy. So if you need that much energy you could install a (very) large battery but this needs to be recharged again later. If thats done with a generator i would suggest using that right away supplying the load.

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ben avatar image
ben answered ·

The 100A+65A is the normal full capacity of a single unit, with even more headroom above that for very short-term transient loads by inverting even more DC from the battery (see datasheet).

However, you may not be able to achieve the full normal capacity (or the full normal capacity for an hour) depending on temperature. There is documentation to show sample derate curves for temperature, but if you are close you need to test this yourself and see how your units behave in your environment.

The pass-through feature does not create much internal heating in my experience -- only using the inverter or charger transformer. So you will probably be able to pass-through close to the full rated amount as long as the unit does not have to shutdown for overheating.

My guess is that you have plenty of headroom in the scenario you describe, as long as you don't lose grid input and as long as your battery is sized appropriately. But as boekel notes, you haven't given us quite enough information to know what you're really trying to do.

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Wessel Wessels avatar image
Wessel Wessels answered ·

We are experienced just that we do get conflicting messages from the market.

As far as the system is concerned, we have the following installed:

  1. Grid: We have grid, it is quiet stable but we have load shedding in South Africa
  2. Required Power: The supporting load to be supported is all linked to the time of day. The biggest challenge we have is that we cannot split the load into essential and non-essential load, as the installation is at the main grid incomer and the load gets split at multiple DB Boards on the lodge
  3. PV System: 128.7kWp SolarEdge System that will be connected to the load site of the Victrons. With SE now allowing Frequency Shifting this site is registered as a Alpha site with SolarEdge to make this integration work smoothly.
  4. Generator: 250kVa Genset, with ComAp controller and it is also integrated with the PV i.e. the PV and Genset will work together in a no grid situation
  5. Batteries: 100kWh BYD 2nd Life Lithium battery pack with intelligent BMS supporting Current Limiting and Load Balancing, with a plan to upgrade it as we understand the usage profiles better.
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boekel avatar image boekel ♦ commented ·

What conflicting messages exactly? (we might be able to learn from this)

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Wessel Wessels avatar image
Wessel Wessels answered ·

Victron SA, told me the Inverter can only handle 100Amps and not 165Amps. Off course if the grid is available and the batteries have capacity.

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ben avatar image ben ♦ commented ·

Well, you should escalate here then. Either the manual or Victron SA must be incorrect. I tend to think the manual is probably accurate.

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