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thechad avatar image
thechad asked

MultiPlus-II 2x 120V PowerAssist Only Line 1???

When the new MultiPlus-II 2x 120V was announced, I thought it would do power share on both lines. But, reading the manual, it appears to only do line 1?

PowerAssist takes the principle of PowerControl to a further dimension. Where peak power is so often required only for a limited period, the MultiPlus-II will compensate insufficient generator, shore or grid power with power from the battery. When the load reduces, the spare power is used to recharge the battery (available on L1 input only).

This is what my current GoPower inverter does and it's essentially useless in an RV installation.

Can someone validate / clarify this?

Thanks!

-chad


Multiplus-II
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3 Answers
Justin Cook avatar image
Justin Cook answered ·

Hi @TheChad, welcome to the Community!

PowerAssist is only available on L1, yes, as is battery charging. L2 is pass-through only until shore power is lost, then L2 is shorted to L1 to provide 120VAC (not 120/240 split-phase) to both L1 and L2.

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thechad avatar image thechad commented ·

Well, that's a bummer. Makes power share pretty much useless when on generator or 30A. Unless I'm misunderstanding. Both generator and 30A already bridge L1 and L2, but they are, of course, separate circuits downstream. Using only L1 for current measurement, I'm assuming it's blind to all power draws on L2 and would have no idea when to add power, no?

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Justin Cook avatar image Justin Cook ♦♦ thechad commented ·

Well it's not blind to power consumption on L2, it just isn't going to do anything about it - adding Power Assist functionality to L2 would require a massive change in both hardware and firmware that would end up nearly doubling the cost of the unit, at which point you'd be better off, honestly, just putting 2 MultiPlus units (not MP-II) in parallel-split configuration and then you do have Power Assist -and inverted power, and charging too- on both legs!

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Matthew Shea avatar image Matthew Shea Justin Cook ♦♦ commented ·

So how I understand it L2 is only active when you have 50A 240v (50A 120v x2) this setup should be fine for most people. you have 50A on L2 when it is in passthrough. all other scenarios L1 and L2 are shorted providing power assist to all circuits. or am I missing something?

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marvs avatar image
marvs answered ·

The manual states:

AC-out-1

The AC output cable can be connected directly to the terminal block ‘AC-out’.

From left to right: “N” (neutral) , “L2” (phase 2), “PE” (earth) and “L1” (phase 1)

With its PowerAssist feature the Multi can add up to 3kVA (that is 3000 / 120 = 25A) to the output L1 during periods of peak

power requirement. Together with a maximum input current of 50A this means that the output can supply up to 50 + 25 = 75 A.

An earth leakage circuit breaker and a fuse or circuit breaker rated to support the expected load must be included in series with

the output, and cable cross-section must be sized accordingly. Victron Energy recommends to use the Blue Sea systems GFCI

circuit breakersPN. 309X or 310X. The maximum rating of the fuse or circuit breaker is 75A.


So it sounds like PowerAssist is only available on the L1 (phase 1) side of the AC-Out-1 split phase line.

I would guess that implementing a split phase power assist would complicate the circuitry in addition to reducing the assist current from 25A total to 12.5A on each leg.

It could be that the available 25A will go to either L1 or L23 of AC-Out-1 depending on their respective loads, until the 25A max capability limit is reached.

Since the device is new we'll have to wait until someone gets one and tests it before we know for sure.



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thechad avatar image
thechad answered ·

Update to this now that I have it installed and have done some testing..

It works exactly how I hoped it would!!!! Way to go Victron!

When connected to 30A or genny (non split phase), L1 and L2 are bridged, so there's really only L1. This means that power share works for the whole system (BOTH lines in the RV)! Absolutely FANTASTIC!!!

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