Sol-Ark 8K/12K AC pass-through efficiency?

[schwizer]

Trying to understand a bit the Sol-Ark pass through power specification (power from grid directly to the load via the inverter). I've marked the spec sheet in red below (8K-P model). 15kW @ 240V and 7.56kW @ 120V (each phase). That seems like a really nice feature so that an entire home can essentially use this smaller inverter and still power everything in the home like normal when the grid is up because 15kW in my case definitely covers the entire home even with electric oven & electric dryer. When the grid is down and the inverter is running from batteries or solar, then i have to be slightly more conscious to not exceed the 8KW @ 240V but that is a small compromise.

Questions:
1. What is the inverter efficiency on the pass-through power? Is it part of the normal CEC 96.5 (97.5% peak) efficiency? That would make sense because I believe the incoming grid AC still has to flow via the central DC bus on the inverter so it has to go through a AC--> DC --> AC conversion to get to the load.
2. Has anyone tested this in real live up to almost the full 15kW @ 240V AC load? I'm just skeptical because the inverter is only rated for 8kW @ 240V AC output in off grid mode which is 50% (roughly) as much.


Regards
Schwizer

 

[sunshine_eggo]

1. Efficiency is DC to AC efficiency. Most inverters are VERY inefficient at low power levels, and they hit their quoted peak efficiency around 30% rated. Efficiency then tapers off a bit to max rated output.

Pass through is pass through. It's literally passing the AC in to the loads. Think of it as having internal relays that connect the grid to the AC output of the unit. Most use a transfer switch in this exact manner. Efficiency should be extremely high since it's not actually doing anything other than drawing power for itself. The 60W idle consumption will come off AC in (or solar if available), and the AC in will charge the batteries as well.

2. The vast majority of Tier-1 inverters have notably higher pass through ratings than they can output in inverter mode. It basically comes down to a higher rating for the aforementioned transfer switch, which is trivial compared to the rated inverter output.

 

[robby]

Well that’s pretty much how I typically use my Sol-Ark but I have never maxed it out past about 13KW.

 

[ddeatrich]

How do you wire/set this up for the pass-through capability?

 

[Oldphile]

How do you wire/set this up for the pass-through capability?

Pass through is from the grid terminals to the load terminals. Provided there's 240 volt on the grid terminals the load terminals are directly connected and only limited by the 63 amp output breaker.