Genset on MP2 AC-in, off-grid

DIY
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1

System: MP2-5000/48, 6xUS5000, two 250/60s with 8.5KW array, planned Fronius PV array with 3.5KW AC coupled.

This post from the archive hits the nail on the head: Which generators are fully compatible? - VictronEnergy

The suggestion there is to move the genset away from the AC-In, and use a separate AC charger, e.g. another Multi on an MK3 interface connected to the GX.

I prefer to move the gen to charging the batteries only, as the freq and voltage fluctuations on the AC side are causing problems, which will likely get worse, when I setup the AC coupling to the 2nd array.

What I cannot get my head around is how to control that charger then, other than manually or through some external control (e.g. HA). Is there a smoother way to integrate it with the GX. I understand that this will not work with DVCC, but do I protect my BMS here from that charger?

The situation I could foresee is poor weather, then a sudden break in the clouds and solar as well as genset are charging. Another factor is that even in overcast conditions, I want to use as much PV as I can get into the batteries in addition to the genset during daytime.

I don’t quite understand how this would work with the suggested Multi on an MK3 connection to the GX.

2

Not a lot of progress on this here. In the meantime I have managed to source a suitable charger, though not the Skylla which is really not suitable here. Too expensive and not enough features, e.g. GenSet control or SOC integration. I wish Victron would offer something here, especially with VE.Bus, so it can be integrated and ideally work with DVCC.

3

It should be fine. The internal charger is 70 amps just over 3kw so the AC coupled array will be used for loads and the internal charger and generator demand will be dropped. Most people set up ESS with generator support if you need it. You program the generator to switch on in the afternoon when loads are high and the sun is low. This way you can run the oven and all the things you need when you come home. You can use DVCC to throttle the internal charger. AC coupled is used first for loads then the charger and ignores the MPPT current that goes into the battery. If you want to automate anything the GX device also has node red integration in the large image. If you have any dev experience it is a piece of cake.