I'm designing a 240 split-phase system for an RV which can take various shore & generator power inputs - 15, 20, 30 amp at 120 or 50 amp at 240.
For various reasons, I'm using a single 230v quattro 8k (configured to 240v/60hz) in my design which will have an autotransformer to create split phase and balanced 120v output.
50 amp 240 input will go to AC1 (in) - straightforward.
The complex part comes with using an autotransformer in front of AC2 (in) so I can connect 120v input ... but my understanding of PowerAssist and PowerControl, etc is limited despite all the reading I've done - so I'm concerned that I won't be able to run from 120v input as I desire.
So here's the thing I'm trying to figure out ... if I need to plug into 120 and
a) charge the batteries and
b) be able to use more than is available on the shore/generator connection, I'd need to use PowerAssist.
In other words, I can't just have the Quattro charge the batteries at X amps and in turn Invert the power that I need inside the RV (so that the "Balance" of the power is either charging or discharging the batteries ... that's basically what PowerAssist *is* from what I can see).
The problem?
The 230v 8k Quattro minimum PowerAssist value is 10.5 amps at 240v which would be at least 21 amps at 120 (remember that AutoTransformer in front of the Quattro). I could in theory still connect to a 30 amp shore line but not a 15 or 20 amp shore line ... and I'm guessing that this would be really tough to run off a 3kW generator (rated for 2790 watts continuous - 23.25 amps at 120).
I guess what I'm wondering is, can the Victron not just charge the batteries from shore (at some limit lower than 10.5 amps) and invert from the batteries simultaneously? Or is that PowerAssist?
If I can't pull this off (and Victron isn't willing to lower that 10.5 to 7), then I could theoretically externally charge the batteries from a 48vdc charger and just Invert from the batteries but I'm having trouble finding a good one (for LiFePO4).
(this is all essentially to cover myself in situations where my solar isn't sufficient to cover my loads / recharge the batteries -- especially the generator portion when I'm boondocking; 30 amp shore power at an RV park should be OK in theory and it's rare that I connect to 15/20 amp... my biggest concern is the generator and I really don't want to go larger than 3kW for portability reasons (nor do I want TWO generators in parallel).
(I wasn't able to think of a design with two parallel 120v units in 120v mode that would work, either)
Thoughts?
