Gas shortage

[Stinsy]

I could switch off the DP isolator at the mains, Turn the breakers off for the EV charging point, Ovens, and hob, move the cable connecting my inverter to the house from the "grid" to "UPS" connections, and then potentially hook a generator up to the "grid connection" having changed the inverter setting to "fast zero export".

I'd then have to reverse the procedure when the grid came back up.

Fine if I knew the grid would be down for a few days or longer, but usually you have no way of knowing how long the power will be out for.

[Caesium]

I could switch off the DP isolator at the mains, Turn the breakers off for the EV charging point, Ovens, and hob, move the cable connecting my inverter to the house from the "grid" to "UPS" connections, and then potentially hook a generator up to the "grid connection" having changed the inverter setting to "fast zero export".

Is there any reason you can't leave that fast zero export setting on permanently? What does it actually do?

[Stinsy]

Could do!

It is for jurisdictions where you're not permitted to export any power to the grid. I hardly "spill" any and would prefer it to be used by my neighbours rather than be curtailed should my battery pack become full.

[openspaceman]

A little briefcase generator MAY not "keep your fridge and or freezer running. Depends on the compressor - generally they have a large start up current and many small briefcase generators are not man enough to start them. I have a nice Honda 650 W generator. It will not start our fridge or our freezer, the compressor just stalls taking loads of current which the little generator does not like. Nothing wrong with the generator I have full load tested it and it is more than capable of its full rated 650W output.

Yes but with most of us having some battery capacity and the inverter capable of 3kVA then the generator only has to charge the battery if the system can run islanded. A 2kVA inverter generator would fill my battery in 2.5 hours run time and potentially put 10kWh of waste heat into the house as well as keep the PV alive.

The issue then is that the charger must be limited to the generator's capability. Some boat generators do just this but the small ones all tend to be diesel, but they are water cooled which is a bonus.

[marshman]

__

[openspaceman]

I was thinking of the Honda EU22i which I would still class as a suitcase generator.

I think the waveform would be good enough to keep the PV live but I do believe one of the victron inverters can continue working in the absence of the grid and the Sunsynk ones too.

Yes I cannot see grid outages being a long term worry.

Calor tried small scale chp back in 1980 but there were not the small, long life, deep cycle batteries then and it had to run synchronously with the grid constantly and didn't last long as a result.

Now with most of our needs being met by PV (excepting those with battery electric cars) I see a small CHP unit run for a couple of hours a day complementing a PV-battery set up for about 5 months of the year when heating is also required, just complementing existing heating.

Yes it still means fossil fuel use but that will not disappear in a hurry and it makes better use of it.

Logically it would be a permanent magnet 3 phase alternator rectified and feeding a dedicated battery charger along these lines

https://www.fischerpanda.de/fischer-pan ... erters.htm

[Oldgreybeard]

I don't know for sure, but would have thought that any of the more modern inverter type generators (the ones that generate DC and use an inverter to turn that into AC) should be capable of providing an accurate and stable 50Hz. In theory there's nothing really different in them from the EPS inverter part of our Sofar, that can generate a pretty good 50Hz output that looks pretty stable.

Be nice to know for sure is a small generator could be used to maintain an islanded system, one where the PV inverter would work and the battery system operate as normal. Much of the time during the day the generator wouldn't really need to do much, just provide something that the systems can sync too. main thing would be either ensuring there was always capacity available in the batteries to accept a charge, or having a load dump of some sort, at least until I can get out and shut the generator down as being no longer required.

We get power cuts here fairly often, especially in very windy weather. I think the longest last winter was around 16 hours, but we did have one that lasted three days a few years ago.

[Stinsy]

The specific mention was "briefcase" generators which I always thought were a max of 1kVA and are almost exclusively petrol in my experience. A 2kVA generator would not be classed as a "breifcase" generator.

I had something like this in mind:

https://www.machinemart.co.uk/p/clarke- ... generator/

[Oldgreybeard]

The specific mention was "briefcase" generators which I always thought were a max of 1kVA and are almost exclusively petrol in my experience. A 2kVA generator would not be classed as a "breifcase" generator.

I had something like this in mind:

https://www.machinemart.co.uk/p/clarke- ... generator/

Funnily enough that is the exact one I was looking at earlier! I reckon it would be just about ideal as a standby generator, and if it can maintain a stable 50Hz, such that the other stuff could sync up to it, then it would be just about perfect.

[AGT]

böhmer-ag w4500i petrol inverter generator 1900w

I have one of these, a bit cheaper stable voltage and frequency and pure sine wave.