EMS in front of MultiPlus ii, Technical questions

[A.Texas.Yankee]

Yes, Dragonfly Energy is claiming the power assist feature of the MultiPlus will aid a low voltage source, according to the quote from Second Chance. I understood it to be like @A.Texas.Yankee mentioned, but I’m not far enough along in research/buy/install process to say yet. If it does, then a Quattro would achieve the goal in your original post by allowing u to eliminate the transfer switch.

100% inaccurate. In a low voltage situation the MPII's internal transfer switch will disconnect A/C input and switch over to inverter only. The MPII (or the Quatro for that matter) will not correct low voltage situations and continue to pass through A/C input. Take it from me the installers of this equipment often know little about it. I'm not a rep for anyone but FWIW, I had a Victron Rep tell me it was not possible to parallel multiple MPII units in an RV and have it work properly. I've now done it twice and now I am putting together a 24v system with 3 inverters this year [emoji6]

[Redapple63]

I believe the Power Share at most will match incoming amps. For example if you only have a household 15 amp plug, the Victron Power Share will at most match that for a total of 30 amps ( 15 amp shore power input and a max of 15 amp inverted battery input from Victron Power Share). That needs to be manually set though. It is not automatic.

Low input voltage is another completely different animal.

Bill

[Brian_]

Edit: Inaccurate information.

[Brian_]

Edit: Inaccurate information.

[JKellerJr]

From page 2 of the Victron MultiPlus II manual:

"
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).
"

Translation: If you have low voltage from shore or gen power the MPII Wwill supplement that voltage, but ONLY on L1. Just so you know for sure what's on L1, I suggest you make sure you verify which is L1 and which is L2 in case they got swapped somewhere along the line.

The power assist feature is for amps not voltage. From the same manual page 12, AC out 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

[Brian_]

The power assist feature is for amps not voltage. From the same manual page 12, AC out 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

It seems you are right. Wow, I have been under the assumption it was both for over a year. I'm glad I never ran into low voltage.

[Longshhm]

https://hughesautoformers.com/

Here’s mine

Attachment 44346

Attachment 44347

You guys are talking way over my head and my comprehension level. That said, JKellerJr and I have the same HUGHES EMS/surge protector (Watchdog), and it has saved our buns on at least 4 occasions from a) power surges, and b) low voltage situations. It also recently picked up on a bad ground connection at the RV park pedestal. I won’t ever hook up without it.

[JKellerJr]

It seems you are right. Wow, I have been under the assumption it was both for over a year. I'm glad I never ran into low voltage.

To be clear, I can't say I'm 100% correct either. I sure don't understand the electric voodoo that goes on inside that box I'm only going by what I have read and I've never seen anything in writing that power assist supplements voltage.

[ExNihilo]

Agree with this thread I have the PI Pedestal 50AMP version and the MultiPlus II. Low voltage is different than low amps. Victron will supplement low amps not low volts.

BTW, if you are on a lower (30AMP) Pedestal- you still need to set your incoming amps on the MultiPlus to the lower Amperage.
The Victron will still try to pull 50AMPs unless you tell it not too. I love the Victron and it is a really smart device but doesn't know that.
Trust me I found out the hard way.
No Bueno!