Zero export system without interconnection agreement

[analog8484]

With a AC -> DC -> AC setup like A VFD would achieve the same thing.
You just size the DC converter and inverter to power the entire RV

Maybe but it seems more complex and costly. The existing implementation is probably the most economical way to solve the problem since many RV inverters already had an AC input for battery charging so the power assist feature could be implemented with little or no hardware changes.

 

[jaggedben]

With a AC -> DC -> AC setup like A VFD would achieve the same thing.
You just size the DC converter and inverter to power the entire RV

Hmm, maybe that is how Victron Energy's systems work and they don't actually operate in parallel.

Edit:
Looking back upthread they seem to have a diagram that says otherwise. For efficiency maybe?

 

[tortuga]

I just don't see it as more complicated than syncing with the grid.
But thats me.
When I build a custom camper / RV again, it will be on the small side and I'll want the inverter to be sized for all my AC demand so I could be totally back country 'off grid'.
Or say when your at a campground and there are 'no plug in sites available' you have full power.
Batteries can charge while your driving or when you get shore power.
Also if your plugged in and the power flickers, no problemo.

 

[analog8484]

I just don't see it as more complicated than syncing with the grid.
But thats me.
When I build a custom camper / RV again, it will be on the small side and I'll want the inverter to be sized for all my AC demand so I could be totally back country 'off grid'.
Or say when your at a campground and there are 'no plug in sites available' you have full power.
Batteries can charge while your driving or when you get shore power.
Also if your plugged in and the power flickers, no problemo.

Perhaps you can draw a diagram for your idea to compare and contrast with the Victron diagram.

 

[tortuga]

 

[pv_n00b]

Based on some recent conversations it seems that there have been zero export systems without interconnection agreement well before the rise of the more recent portable units. I learned that many RV/boat inverters (e.g. Victron, etc.) have had a "Power Assist" (https://community.victronenergy.com/questions/29128/power-assist.html) feature for quite a while.

I would not hold up any vehicle power system that plugs into utility power when parked as a standard for what can be done with a building that has utility service.

 

[analog8484]

View attachment 2559556

That should work but definitely more equipment/cost. Also, a bit exotic (120VDC inverters are not common).

The Victron (and other similar converters) provides a simpler way to tap shore power. The way these low frequency converters work requires no hardware changes and only relatively simple firmware changes to consume shore power or provide power to load. The difference between charging batteries from shore power and discharging from batteries to power loads is just driving the AC output voltage a bit lower or higher than incoming shore power. It's actually a very elegant mechanism. So, using the exact same hardware and shore power connection, these converters can be easily configured to always drive their AC output voltage a bit lower than shore power to operate in "charger only" mode and be perfectly compliant with the existing laws/rules. Kinda silly and shows the shortcomings of the laws/rules.

 

[analog8484]

I would not hold up any vehicle power system that plugs into utility power when parked as a standard for what can be done with a building that has utility service.

What real differences do you see with respect to interconnection rules/laws?

 

[tortuga]

That should work but definitely more equipment/cost. Also, a bit exotic (120VDC inverters are not common).

I just picked 120V same concept with any voltage really.

The Victron (and other similar converters) provides a simpler way to tap shore power. The way these low frequency converters work requires no hardware changes and only relatively simple firmware changes to consume shore power or provide power to load. The difference between charging batteries from shore power and discharging from batteries to power loads is just driving the AC output voltage a bit lower or higher than incoming shore power.

Thats interesting, I'd love to see a tear down on eevblog or someplace like that.
I'd still mostly use my system 'off grid'