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eregister avatar image
eregister asked

Multiplus is assisting when there is enough shore power available

I have 2 multiplus configured for 30 Amp -120v in parallel.

Color display shows shore power at 2400w with AC load at 3200w,

Input current is set to 30amp and currently showing using 25amp.

Batteries are assisting with 800w. So my question is if there is enough supply AC to power the entire load why is it getting an assist from the batteries? It is nearly dark an solar is only providing about 100w.


Other information to note. These units are wired for L1 and L2 of 50Amp input for RV. When on 30 amp power I reprogram for 2 units in parallel but don't reconfigure any wiring. Just use a 30-50 amp adapter. Unit L1 provides powern inverting and charging unit L2 provides inverting only and showes no shore power as it is on the same phase of power.


Numbers are approx. See screen shot below


screenshot-20220426-180452-chrome.jpg


Multiplus-IImultiplus in parallel
screenshot-20220426-180452-chrome.jpg (317.7 KiB)
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Paul B avatar image Paul B commented ·

have you got ess setup by chance and if so check the grid set point settings and other settings in that area-

any other settings that you may have changed in the setup - also please advise

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eregister avatar image
eregister answered ·

ESS is not setup. Only have modified settings for lithium batteries and how to charge

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ig44 avatar image
ig44 answered ·

I have the same question/problem with MultipPlus-II 48v/3000w 220VAC

- a 2000w generator
- maximum AC input current set to 8.5A (ie 1870watts @ 220V)
- a 1800watt load on AC1-Out
- MP2 will only draw say 1500watts from the generator... and Invert/Boost 500w

(Obviosuly) the desired outcome is that the MP2 would *not* use batteries when it doesn't have to !!
ie AC-In = AC1-Out...


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JohnC avatar image JohnC ♦ commented ·

@IG44

In your case, just multiplying out V and A can be misleading. As an example, this is my base house load from a Multi.. 1652612754977.pngNasty Power Factor from typical appliances.

And if you have 'Weak AC' checked in the Multi it will force a poor PF on ACIN as well as severely restrict input.

Just sayin, take care with the obvious..

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ig44 avatar image ig44 JohnC ♦ commented ·

thanks...
My example was the input/outputs watts measured by the MP2 (as displayed on a Cerbo console), not the claimed wattage of the load. So guessing PF will already be accounted for.

If I jiggle load switches and Max AC In amps... I can get the MP2 to use the full generator current and use less/no PowerAssist... with the exact same load/devices. So I concluded it was the PowerAssist algorythms and/or current sensing.

Could it be that the MP2 is sensing AC In (I have current sense) seeing say 1500watts at the time from the *invertor* generator, then just boosting with 500w PowerAssist to give the 2000w that AC Out demands - rather than trying to load the AC In with 2000w (up to the Max Input Amps)?

Soon I'll take a screenshot soon from the Cerbo... and how I "trick" the MP2 to doing what I want it to. This may better explain my situation.


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ig44 avatar image ig44 ig44 commented ·


AC Input max amps: 8.5A

#1 - Start Generator

1652656402213.png

1652656634188.png


#2 - turn on load

1652658808018.png


1652658794119.png


:-(
AC-IN drops
I'd prefer to maximise generator out so I can shorten the generator run time

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JohnC avatar image
JohnC answered ·

@IG44

There may well be a 'safety margin' applied to the Input Current setting. I don't know this for sure, so just guessing that this is the case. This from one of my gensets (inverter reg) a couple days ago..

1652671456690.png For about the first 75% it's in Bulk, then Current starts tapering when Absorb reached. Input Current Limit is set at 10A, and the actual 9.0 to 9.6A. I've no idea what the variation is caused by, and it may be worse with spiking, as this is only per-minute sampling. Might even be something like varying brightness on a tv at the load end. But if I wanted it to average 10A input, I'd set the limit higher to compensate.



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ig44 avatar image ig44 commented ·
thanks...

I've also tried setting the current limit higher...
but the generator circuit breaker trips when some 240VAC loads are switched on :-(


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