It sounds like these things do something I don't want. What I want is something that masks short outages completely, so that I don't have to walk around the house afterwards resetting all the stupid clocks and so my computers don't reboot and los their state, and my TV recorder etc etc. I don't mind if everything goes down after a longer outage; that's what will happen in a very long outage anyway.

It's exactly the dropouts caused by short-duration automatic network switchovers that are my problem here. We get far more of them than I've ever seen before and I find them a real nuisance.

I don't think the suggestions about the behaviour can be quite right. Whatever system already knows the phase of the mains at the time the power goes down. It has to for microgeneration to work. And it causes a lot more inrush current and weird power excursions to restart an induction motor than to keep one running. UPS systems manage to keep continuous power. I can understand there might be a phase matching problem when restoring power; I don't know anything about how that is handled.

Posted by me on the previous page:
"some stuff in G83 about it."

My bad, G83 is superseded by G98.

My 30 second comment is when the grid goes down it is detected by the inverter and does certain checks to ensure that it is safe to switch to battery if it switched to battery before doing its disconnect from the grid then it could end up powering your neighbours houses or electrocute a person working on the line. When grid comes back on it is detected by inverter and resumes normal operations. I too am frustrated by having to reset clocks when there is an outage but the only sure way is to be totally off grid. The Ed posting is interesting as I was not aware of the Victron product but bit late in the day for me now. The Tessla system which is expensive also has a delay but a bit less than 30 seconds. if you go here

https://fullycharged.show/episodes/tesla-powerwall-2-update/

Robert Llewellyn has video of a Tessla gateway battery system installed and demonstrated at his house.

Commissioned my system today. Taken me ages to install did it all myself in the end as 4 requests to sparky to connect me all up fell on deaf ears. Was mainly overcast but bright and occasional bit of sunshine. Battery as delivered was 30% full in 4.5 hours was practically 100% . Impressed with the charging rate. Most of the PV produced went into the battery the rest to the grid or boiling the kettle.

Posted By: Brian Fauxdoes anyone have any news of the Ultrabattery?

I presume you've looked at their web site? It appears to be available but mainly in America and Japan and only by negotiation with the company. I suppose you could see if they have any interest in your project?

Posted By: Brian Fauxit would have significantly replaced the standard LeadAcid battery by now

I expect that depends a lot on its price. And I expect it's significantly more expensive than regular lead-acid cells, both because of the cost of manufacture and a desire to extract a premium price. Hence their search for niche applications like hybrid EVs - not regular cars and not regular EVs, just hybrid EVs and only a subset of those.