Solar Backup for Power

Nalz · 22-07-2021 12:12pm #1

Hey folks

Apologies for the lack of info and if I'm posting in the wrong area!

I'm looking for advise in purchasing a solar panel powered electricity back-up. I recently bought a house which has solar panels for heating the water only, and have had two power outages in the last 3 months so looking for a back-up plan. Even if its just 4 or 5 hrs powering the house or a section of the house (laptop, wifi & freezer being the priorities)

I don't have much of a budget, maybe I can stretch it probably to 2.5k

Any help greatly appreciated!

graememk · 22-07-2021 12:57pm

First of all, are you looking to get solar installed on the house?

These are grid tied, so power goes off, they shut off for safety and to protect people working on the lines.

Then you can have hybrid inverters with storage. They usually have an emergency power supply that is run off the batteries (and maybe can be supplemented by the solar panels on the roof, depending on how it's configured).. then your into changeover switches etc etc.

To do your job, a couple of UPS (uninterrupted power supplies) could be exactly what your after.

Powercuts that are unplanned are usually at night/during a storm so solar itself isn't much use.

RainInSummer · 22-07-2021 4:45pm

A tie in point for a generator and a decent generator would be my recommendation. It's saved me multiple times.

Solar knocks off when the grid knocks off so it can't back feed power up the line and fry some engineer trying to fix the issue.

It's not a back up solution.

RainInSummer · 22-07-2021 4:47pm

Nalz · 22-07-2021 5:23pm

I'll need to re-read both of your replies a few times, some of it went over my head.

Is there not back up portable solar panels that would power a battery that could keep a few devices going for 3-5hrs?

graememk · 22-07-2021 6:23pm

Yeah I think I've heard of a few. Likes of blue yeti and stuff like that.

Forget the solar panels for it, easier to just keep it charged from ac. You'll not have enough panels to keep it charged from solar when there is a power cut.

Something like this https://youtu.be/jF3CPw84-bE ?

RainInSummer · 22-07-2021 8:05pm

Don't consider solar for a back up solution.

If there's a storm in winter or at night solar is useless. Even the array on my roof would be useless in winter to charge a battery.

A UPS is fine to keep a few things going but it'll have it's limits too.

I notice you didn't say how long your power was gone. What's your expectations on how long you'd need things to last?

To explain the point I made earlier, a tie in point for a generator is just a socket on the outside of the house where you can plug the generator in to. This will feed power to your fuse board. It effectively replaces the mains.

Critical in using a generator though is a switch where you absolutely cannot feed electricity back to the grid. It's the same principle about solar not working when the mains is down. You don't want either set up killing some lad fixing lines.

RainInSummer · 22-07-2021 8:08pm

Oh and Goal Zero are the manufacturer of Yeti stuff AFAIR. They might have solutions but they'll be expensive and when I was looking at them they were really only good for charging phones and camera batteries.

They'd not run a fridge.

Nalz · 23-07-2021 8:55am

The longest the power has cut was 4hrs

SD_DRACULA · 23-07-2021 9:55am

You can probably look at an AC battery but don't think your budget will cover it as it might need some sort of inverter/charger also

Nalz · 23-07-2021 10:52am

https://boards.ie/discussion/comment/117650356#Comment_117650356

Cool thanks! What would you be talking roughly?

SD_DRACULA · 23-07-2021 11:47am

No idea, never looked into them but maybe something like a pylontech 2.4/3.5kwh battery and a hybrid inverter can do the job (feel free to correct me guys)

https://solartricity.ie/battery-energy-storage-systems-ess/ - batteries

https://solartricity.ie/solis-hybrid-off-grid-energy-storage-solar-inverter/#singlePH - inverter

That is if the inverter can be used without a solar pv system but it is expensive to use just for that and installation won't be cheap unless doing it the DIY route.

graememk · 23-07-2021 5:07pm

I wouldn't even consider a fixed system solely for a backup.

If you could find an Irish supplier for something like this : https://www.amazon.co.uk/POWEROAK-Portable-Station-Generator-Emergency/dp/B08RRNRCX5/

That has 2kwh of battery storage with 2 kw sockets on it.

There's a 1500w one too and that will run what you wanted easily. That's a bit cheaper..

Run extension leads to your freezer (which would be fine for a few hrs anyway - just don't open it!) And laptop, routers, etc.

reklamos · 27-07-2021 5:13pm

Solar is not suitable as backup power. Backup power must accessible on demand and solar depends on too many factors.

I would say your best bet is generator or a simple UPS.

RainInSummer · 01-08-2021 8:39am

https://www.boards.ie/discussion/comment/117650082#Comment_117650082

That's not too bad. My longest was 5 days, with a couple of four and five hours thrown in.

I'd still recommend a generator with appropriate work on the fuse board over a UPS. It'll power more and keep running indefinitely as long as you keep it topped with petrol.

https://www.doyles.ie/products/victor-generator-3-7kva-up170-208cc-avr-gg3300bev.html?filter_set%5B%5D=1330,1354

That's the yoke I have. Got it for €500 from a local lad. Don't forget to factor in the price of the electrical works so you can isolate it from the grid.

Only other consideration is noise if you're in a built up area.

unkel · 10-08-2021 1:47am

5 days? That's insane. I can understand that you would have to buy a dirty fuel solution if you don't own an EV. If it's just a few hours, a battery pack like the one graememk linked to will do the trick. And of course, anyone with an EV is laughing anyway. Just connect a pure sine wave inverter to the aux battery of your car. I can power the base load of my house from my car (with a fully charged battery) for about two weeks!

Del2005 · 10-08-2021 3:21am

https://www.boards.ie/discussion/comment/117731335#Comment_117731335

And when you want to leave your house how do you keep everything working?

unkel · 10-08-2021 10:21am

I would then use my other EV ;-)

RikKav · 20-08-2021 11:41am

https://www.boards.ie/discussion/comment/117731335#Comment_117731335

Hang on unkel. You may have just blown my mind. How easy is a sine wave inverter to instal?

RainInSummer · 25-08-2021 9:33pm

The 5 days were an exceptional occurrence. The big snow of 2018. Beast from the East or whatever it was called.

Call me paranoid but I think those events will be more frequent.

Most outages are in the order of minutes, with the odd one lasting a half day or more. That's not wholly uncommon depending on which part of rural Ireland you live in.

I do own an EV but to be honest the house was wired for a genny and it's handy for heavy kango drills and power washers when I'm up the garden.

I wouldn't be without one even though I'm no fan of having 20l+ of petrol knocking about the place.

slave1 · 26-08-2021 6:46pm

You're paranoid

RainInSummer · 26-08-2021 6:49pm

I'll take paranoia over inanity any day.

Solar Backup for Power

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