Problems with Victron Powerassist / Upgrade inverter capacity

[Ulstue]

Here in the forum an example was brought to get a high inverter power, e.g. to cook with an induction cooker. The Victron Quattro, Multiplus / Mastervolt Power-Assist is designed to boost weak shore power or generator power. This can be used theoretically (or by forum members here in practice) to connect another inverter instead and increase its power.

I have therefore contacted Victron. The guy there went directly to my throat in the figurative sense. He insisted, that this leads to problems (which are not covered by warranty) but did not want to say what kind of these vague problems are. Instead, he almost yelled at me that I absolutely have to buy two Quattros for parallel use instead. (each over 3000,- $).

Mastervolt also refuses to connect other inverters to their powerassist function without any explanation, so my dealer told me.

What is this all about? Does anyone know what problems this can lead to? No generator produces directly 120 or 230V AC, which means that the AC from an AC generator always comes from an inverter.

Is this just a "particularly clever" sales trick, or is there really something in it? It is clear that energy saving functions or other controls of the connected inverter can be switched off, but then exactly the same current comes out of a 12/120 or 12/230 DC/AC as from the shore connection or the generator. Or not?

Any ideas what the problems might be?

[RickG]

I guess that depends on your cooktop specs. The cooktop we had at our house was 240V with a 40amp breaker. That is more capacity than our Multiplus 3000 can handle. But, a single burner 12V 15amp induction cooktop would work fine; not a bad idea as backup to propane. I'm not an electrician. So, personally, if I was thinking about installing an induction cooktop I would hire an electrician.

Cheers, RickG

Cheers, RickG

[swampbush]

It works fine to use an inverter to supply power to a multiplus. We have an easyplus 1600va that is always on. When larger loads like cooking are required the multiplus 3000va is switched on. It can be left on all day, but draws nearly 2 amps a t 12 volts.

It does require discipline to remember to turn the larger inverter on. No different I suppose than turning a Genset on to cook. This is assisted by a large flashing beeping alarm that comes on if the pre alarm on either inverter comes on. These are wired to the relay output on the inverters.

Only initial issue was that the power would drop out as the easyplus synced to the larger inverter. After disabling the UPS feature of the easyplus it works perfectly.

Charging is completely disabled on the easyplus as it's small charging isn't required. Otherwise you would have to turn charging on and off when switching from shore power to inverter power. The 3000va multiplus has 120 amp charging which is enough for us.