Victron Quattro Current Limiting & Power Clarification

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badengineer8977 asked Apr 23, '19

Victron Quattro Current Limiting & Power Clarification

I am currently proposing the integration of a single Quattro 24/8000/200-100/100 unit. I am curious if anybody knows how these units operate during "current overloading" conditions from a DC standpoint. So if the unit is set for maximum 200A max DC (DIP SWITCHES) charging and the units is overloaded (Dead Battery, Heavy Auxiliary Loading, etc), does regulation set in and begin to reduce the charging voltage on the DC terminal to reduce current? Does it sort of just cycle back and forth keeping current below the maximum setpoint or can the system go into 100% overload and "open" circuit the DC terminal? I've read that most chargers follow a 3 step charging profile initially keeping current constant by modulating the output (varying DC) to achieve constant current profile as the battery begins to charge up and battery impedance decreases over time. Curious if these units will do the same or can i dump the unit during overload....

And can somebody explain the "Inverter" power specs on the data sheet?

Continuous output power at 25C 8000VA at 3:1 crest factor

Continuous output power at 25C 6500W

I'm lost with those two specs. I understand crest factors (AC perspective) greater than 1.4 are due to non linear loads (rectifiers, etc) but what if we have a purely resistive load with a power factor of 1.0... Can we get 8000W since 8kVA = 8kW when PF = 1.0? Totally lost on this one.

THanks!!!

current limit

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Answer 1 · 2019-04-23T20:59:45Z

ben answered · Apr 23, 2019 at 08:59 PM

The DC charge current will always be regulated down to whichever is the lowest of these:

1) max charge current you specify

2) max charge current of the unit

3) max charge current whereby the internal components are not getting too hot

4) max charge current to avoid battery rising above specified voltage, when in absorption or float

5) max charge current that still leaves enough AC input power to meet the load demand, while keeping AC input current below the specified maximum AC input current

If any of those conditions result in a charge current of 0A, the Quattro will just stop charging. It will not "open circuit" the DC terminal.

If Quattro is in hybrid assist mode, condition (5) could result in a calculated negative value... at which point, current will flow the other way, and the battery will be discharged.

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Answer 2 · 2019-04-23T21:01:46Z

ben answered · Apr 23, 2019 at 09:01 PM

Regarding power maxima, I took the specifications to mean 8kVA or 6500W derated for typical PF. So with a true 1.0PF it should be able to produce 8kW. However, I have not verified this on my units.

I will say that I have noticed most of the specifications are somewhat aggressive -- typically, the units I have cannot actually quite meet the specs. You should leave some headroom or plan to do a lot of testing.

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Answer 3 · 2019-04-23T21:57:58Z

badengineer8977 answered · Apr 23, 2019 at 09:57 PM

Thanks for the response Ben and thank you for bringing up Hybrid Assist Mode. I totally forgot about that feature. It may be something we will likely investigate as our HVAC power demands exceed whats available from a 30A 120V shore cord.

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