Loop-issue with combined Multiplus 12/3000/120 and Phoenix 50

Q&A and troubleshooting
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Hi victron experts! I have a loop-issue with my set-up of my combo of a multiplus 12/3000/120 and my Phoenix 50 in my boat. Typically, shore power access is 10A 240v, providing 2 400W AC power from shore. Given the additional 2 400W inverted through my multiplus, I should have ~4.8 kWh available onboard. My phoenix 50 is connected to my multiplus II AC-out-2 output. These items are connected to a cerbo2.

So, my issue is: When connected to shore power, and using more than 2.4 kW AC power onboard, thus inverting from the battery bank in addition to full 10A shore capacity, my phoenix chargers starts to charge my battery bank due to a drop in voltage. This eats of my available shore power capacity, increasing the need for inverted AC power, again increasing the charge current from my phoenix.. this escalates to the phoenix consuming approx 900W of shore power, reducing my total capacity from 4.8 to 3.9 kW..

How can I avoid my phoenix eating from my AC shore capacity while inverting from the battery bank?? I need both chargers online to feed all three onboard battery banks;

  • the Multiplus serves my utilitites-bank
  • the Phoenix primarily supports starter and generator batteries, but also has one channel fed to utility bank to increase charge speed when docked (reaching 170 A charge speed in total).

Any way I can solve this issue dynamically and still maintain the extra 50A charge speed to my utility bank provided by the Phoenix?

I have considered adding a relay shutting of the 12V charge feed from the Phoenix to the utility bank when the inverter on the Multiplus is working, but I hope there is another way.. Anyone solved this before?

Jens-Olav

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Unless you can somehow disable ACout2 when in power assist mode, the solution is logically impossible.

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Could it be possible to trigger a Cerbo relay to provide 12V to a remote switch, cutting the utility bank output on the Phoenix charger, when the inverter state = ON as the event triggering the relay 12V output?

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I would guess that the Phoenix charger has a ‘remote’ control loop somewhere on it’s terminals. This can be controlled by the Cerbo relay contacts - no external power normally required. Then ther cerbo relay can be manually controlled, or automatically by node red or similar.

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