Solar in a blackout

I'm not an electrician, but it sounds like that probably wouldn't (shouldn't?) work. The whole thing about the inverter is that it pumps out a higher voltage than what it detects as the grid. So it would use it's voltage over the grids. So if the grid was reading 220v, the inverter would do 225v or something. If you feed it it's own supply, wouldn't that just create a circular feedback loop? Raising the voltage until it goes out of tolerance? (230v +/- 10%) I guess you could lower it (the voltage), but really, there are probably better solutions. Dedicated UPS boxes and the like.

However, using your backup 3 pin outlet on the inverter, why not just run a 10m extension cord off it and plug in the telly or whatever you want into it. If there was a blackout, it probably would only be for 2-3 hrs max, no?

Several blackouts here so far this year mostly so far in the summer lasting from 1-5/6 hours. Solar has been a blessing in this time.

I have no fireman's switch on the panels and instead just a DC isolator in case of issues. Fitted a generator switch beside consumer unit and in event of outage just click the generator switch and house runs perfectly off both batteries and solar generation whilst keeping batteries topped up. I also turn the AC switch off at the inverter so it is not receiving its own power back

Yes all approved inverters in Ireland from what I'm aware have anti islanding so designed to shut down in event of grid outage

I suppose it's there to isolate in case of house fire the panels but in my case is in ground mount outside and easily reachable. But agree that surely one of the most important parts of having solar is that you will have continuous power as long as the weather plays ball. But to see a sunny day outside and house with no power during a grid outage is just wrong imo

I grabbed two 100aHr (2.4 kwhr) lesiuire batteries (400 cycles AGM) for around 130euro each, a 1000W pure sine wave inverter, a mppt charge controller and 300W panel. This easily keeps the house going with broadband , access point, lights and tablets for longer than any outage we've had.

All this was around 550 euro and should do me for most of the rest of my life. 🤣

I've a fire man on my ground array and can't think of an easy way around it either!

The reason (briefly) is that the wiring is a two way circuit. When you house needs power you take it from the grid, when you have excess you can give it out.

Problem with a powercut/blackout, is that your inverter doesn't know if the grid is down for a deliberate outage, or the electricity cable down the road knocked down by a tree. So for the tree issue, ESB "power down" that area so the electricians can go work out and safely work on the fault. If in the meantime, you are quiet happily chucking 220v out into the wild, while ESB have turned off their side, your about to give some poor electrician a bad day.

So when inverters detect no grid voltage, for safety reasons they will go inoperative. Now in theory you could safely set one up that it can work in an outage, but it requires creating separate isolated circuits in your house. Most people, unless you have some skill in the area should avoid. I know enough, to know enough that it's not worth it for me.

the two together are 2.4kWh, not 2.4 each!

I am not familiar with the Ecoflow. I just took a look and the battery chemistry is different to that battery I have. As it's lithium if will have a better depth of discharge, closer to 0% (but I'm not getting into that argument !), where as most LA batteries shouldn't really drop below 50%. Also, the weight difference is huge. Still, for what I need the AGM's are perfect.

I see the Ecoflow is just 18650 cells. If you were anyway handy you could make a pack with new (or used) 18650's, a BMS, inverter and the sockets/ports for an awful lot less that what they're advertised as. The do look handy though!

Sorry for asking a dumb question - but how do you get an Ecoflow to power your house during a black out? Presume you cant just plug it into a socket and it works in "reverse" ?

https://www.aliexpress.com/item/4001083766967.html

LifePO4 is safer than 18650. Also cheaper. The set about was 1275 last week. 10.24kWh.

Anyone got any recommendations for some UPS boxes? Thinking of maybe ~1.0 Kwhr or there abouts for the telly.

Thanks.

If you have a Solis inverter their is a backup plug on it, so i just put a single socket on it and during a power failure I just run the extension lead out to it.

Now depending your battery output that is. I'm lucky our setup can output 3.5kw. no problem for coffee makers or a kettle. I could easily run the TV router and sat box for a number of hours, god forbid we have to acutely talk to other members of your family.

Knowing your setup is key to this, you need to understand what it can or cant do.

Many people with solar and a battery have this in place without knowing it. TBF you paid a lot of money for it, why would you not try and learn what it CAN do for you.

NOTE, not all setups are the same and some don't have this facility.

Any links/brand names and models for the components for us newbies to this game?

You make it seem so easy! Many thanks for those links. When I searched leisure battery I was getting random things over €1000. Halfords makes more sense.

I am sure I will have a ton more questions, including how to get this past the other half, but very interesting.

Edit: First question! Somebody, possibly bullit_dodger in the solar pv quotes thread, suggested some ideas for garden mounting, and one option would be on a vertical wall. I know, not ideal from a capture stand point, but possibly the only place I could do it. Is there anything specific I would need or could I just grab the cheapest roof mounting rails and use those? Would be looking at mounting to concrete fence pillars.

Depends where you live I guess. In an urban area, unlikely to be lengthy power cuts as even in storms, faults in such areas get fixed first. Living rural you could be waiting days, standard generator is the way to go to get water into the house and charge devices. After that, rechargeable lanterns and solid fuel stove.

Mentioned previously (sorry can't remember who to give credit), but most inverters or the batteries themselves have an 'emergency' outlet so if you have a battery in your solar installation a cheap-n-cheerful solution would be to run an 20m extension cable from that outlet to the living room and plug in the telly and or router (assuming your load network hub has power but that's another problem for another day)

Depends on how accessible your installation is of course. But might be a lot easier than building an off grid solution? (but it's a lot of more fun to come up with an off-grid solution to be fair)

What is the most per hungry thing you run?

7Kw is a nice size!

What if I make a pretend grid supply?

Turn of grid at meter box. Have a small battery plus inverter to generate 220V (or could it be lower like 210V) that you can switch into the primary output of the solar inverter. Turn off any heavy power using equipment. The solar inverter and fireman's switch would think that the grid is up and running so the solar would work away. What are the issues with this approach?

Does the solar inverter need to sense the flow on the CT clamp in order to work right?

I have a Solis inverter (2.4Kwp) with a Pylontec battery installed a year ago. If I knew then what I know now and how the setup is configured to operate under various circumstances I would not have invested in a battery at all as I do not believe that they are a great bang for your buck. The Pylontec (2.4kwh) was €3k + vat. You would think that for that money you would be able to run your house for a decent amount of time. What I have found is that it will run the house from maybe 6pm onwards for the rest of the day on a full charge. However, turn on one of the big drainers ( oven, dishwasher, washing m/c etc.) and it wouldn't pull the socks off a deadman! So for me at the moment it feels like a bit of an expensive ornament 😁.

Which, leads me to the reason for my post. I have a long extension lead connected to the backup outlet of the inverter. Reading previous posts I see now that during a blackout I will not have supply from the panels available ( it's all in the small print isnt it 😕) and would be solely reliant on whatever SOC is available via battery. I have been trying to configure the solis not to discharge the battery so that at least I have maximum charge available for an outage ( at least configure it this way during winter period when conditions would not be generating really any excess charge to battery anyway). I have not had any success though. I have tried to configure the discharge time to a few mins a day but Solis seems to ignore that setting. If there is any charge there it will feed it to the load regardless. Can I just turn off the battery when fully charged and turn it on again when there is a blackout during winter? Or am I stuck with the expensive ornament!😁

@jkforde It is already configured to charge off grid by installer (00:00-01:00) but come 8AM has drained to its discharge SOC. I'd still be at the mercy of good timing of a blackout and having sufficient charge built up.

There has to be a better solution.