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stgermain45 asked

Adding Victron Multiplus in Parallel

I have a Victron Multiplus 3kVA 120V purchased June 2020 (Part #: PMP123021102). I'm realizing I'm in need of more (faster) charging power and more inverting power on occasion. Some questions:

1) Will my Multiplus be compatible to wire in parallel with a new one purchased now?

2) I've read through the parallel wiring manual and understand the considerations to AC and DC wiring, etc. I'm bummed to read on these forums that wiring in parallel means both Multis need to always be powered on and turning one off means the first Multi drops output/faults unless reconfiguring for standalone use. Is this still the case? This would be extremely limiting in my case as my need for faster charging (4x 200A Victron LiFePO4 in parallel, 800A bank on a boat) is only on occasion. I could wire for standalone of both units but (a) I have a single CCGX installed on a Raspberry Pi for monitoring and do not want to add a second just to monitor another Multiplus, and (b) I need more inverting power as my 2 air conditioning units (16000 BTU and 10000 BTU) are wired through the inverters and there is not enough inverting power to turn on the compressor of the larger unit, even with soft starts installed.

3) A bit unrelated, but in my installation I have never seen Power Control work quite right, though I believe it is my fault for going on assumptions. While running on generator power, I tend to limit current with the multi control panel to 40A. I have a Victron AC current sensor installed on the Multiplus and it shows up on the CCGX as "PV Inverter" (wish I could change that label). A few loads on the boat do not run through the inverter as they are very large loads especially on startup (dive compressor, watermaker, and a separate 100A battery charger which I intend to replace with the new Multi). Taking these loads into account when switched ON was my reasoning for installing the current sensor so that the Multi would know about them for Power Control reasons. Will the Multiplus limit charging in also taking the AC current sensor loads into account? I'm finding that it does not, but maybe there is some configuration required.


Appreciate any guidance.


Thanks,
Chris

MultiPlus Quattro Inverter Chargerpowerassist
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3 Answers
stgermain45 avatar image
stgermain45 answered ·

Anyone??

I did recently read of the upgrades to the Victron Connect app in terms of configuring the Multiplus. This seems it could be an ok (but not ideal) workaround for easily reconfiguring Multiplus units into standalone without breaking out a laptop and plugging in via MK3-USB. If doing so, would the VE.BUS BMS and AC Current Sensor Assistants be lost? Does the ethernet cable between the units need to be unplugged transitioning from parallel use to standalone?

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shaneyake answered ·

1. Depends, what is your HW rev number? You would want the same rev number.

2. Yes, they will both have to be on all the time as they act as one big inverter. You can not easy reconfig standalone vs parallel.

3. There seems to be something wrong there, as if you set an AC limit of 40A the max input power should be 40A, if you turn another load on the Multiplus should reduce it's charging rate to keep Input at 40A. If power assist is on the inverter will ramp up to keep load at 40A.

You can run in an unsupported mode of cascaded but you will probably run into some problems during charging. I would just parallel and call it a day. You will have tons of power and it will just work nicely, however your standby power will be double.

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stgermain45 answered ·

1. Looks like HW rev 01. Firmware version 2702430.

2. Leaning towards parallel configuration but will probably test how easy it could be to switch between standby/parallel with the new software revisions to Victron Connect.

3. Well, I guess my question is this: Does the Multiplus AC limit based on what it senses at the inverter input ONLY or can it be limited by what the AC Current Sensor tells it? The AC Current Sensor is installed on aux input 1 and is configured as an Assistant.

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