question

Only the old style Phoenix Inverter with VE.bus are able to be connected together for parallel/3-phase/split-phase.

https://www.victronenergy.com/inverters/phoenix-inverter-12v-24v-48v-800va-3kva

For 48V they are only available as 230V, for 120V there is only a 3kVA model.

The cost difference between a Phoenix inverter and Multiplus inverter/charger doesn't look significant.

If you are planning an upgrade in the future be advised that you can't switch AC or DC voltages on these units. So you would not be able to buy a 24 volt model now and upgrade to a 48 volt system in the future without buying new units.

Hi, this may not be relavent and you should know up front that it IS NOT A SUPPORTED recomended solution... However :-

I am off grid and origionall installed a multiplus 48/5000 ith a BYD battery.
I have an LPG generator for backup and solar feeding the DC, all absolutly standard and configured as it should be.

I was looking for additional capacity and redundency and went with a second inverter charger however my budget would not stretch to another large battery in one chunk.

My solution was t feed a 24/5000 with the 48/5000. The 24 has its own battery bank and when I need more than the 5000VA the 48 can supply the 24 operates in assist giving me potentally 10000VA.

The 24 has a Cerbo GX, large OS, controlling things and thus far all is working well.

I, and this is an opinion not a fact, do not see why a Phonix couldnt feed the AC IN on a Multyplus. Obviously not at the same time as a generator.

I also think it is fair to say that the comunity seems more open to novel setups, now, than it was a few years ago but at the same time there are very good reasons to keep things standard and supported, particularly if you ae not prepared to handle your own config and accept some risk. How much risk well, thats the rub... If you go unsupported then quantifying risk is well unsupported.

I like my particular solution and feel that it serves my 'use case' / circumstances better than a paralell solution would have done. However you should think long and hard before basing a system design on a budget. Generally I would suggest getting the right kit for the job will serve you best in almost all circumstances. This is especially true when considdering upgrades/expansion in the future when a small amount of penny pinching now could easily shoot you in the foot later.

Its not an easy dicision IMHO... Sometimes the obvious decision will not be right and or even dooable, whilst at the same time working outside the box shoud not be taken lightly...

If you want a difinitive answer it will be a supported solution because a load of clever fork have worked very hard to make this stuff work well in a variety of circumstances.

If you decide to configure something different you may get some help but you cant reasonably expect full support and or definitive answers to setup questions. This can be frustrating but is ultimatly your choice, in terms of where you go with your setup, and is an absolutly sencible and necessarry limitation when it comes to supported solutions.

Make sure you are comfortable with what you get into. I am, but I cant recomend that anyone els go there, because victron experts wouldnt, for good reason, in most cases.

I hope this perspective helps you decide... Think long and hard.