Plug in Solar

[VicParticipant @vic]

There’s lots in the news about this at the moment. Time to do some research.

https://modular.solar/?gad_source=1&gad_campaignid=23555894566&gbraid=0AAAABCzlhQLlcNAL1R83jHR6TdB-3LDfF&gclid=Cj0KCQjw1ZjOBhCmARIsADDuFTDI1_2Ch9j9WjAhkombYkIfFFBUwg3RmjrP4xkWXavd17p68OuDHnoaAiNlEALw_wcB

[Robert Atkinson 2Participant @robertatkinson2]

Wow, ” 340kW produced per unit”!  Thats 14 times the maximum power from a standard (100A) UK mains supply. And only £450, it’s almost unbelievable……..

On a serous note, plug in solar power are NOT LEGAL in the UK at this time (March 2026).

Robert.

[duncan webster 1Participant @duncanwebster1]

They claim 340kW per unit (presumably panel). That needs to be taken with a shovel full of salt, never mind a pinch.

Robert beat me to it

[OldironParticipant @oldiron]

Read further down. It says ” recharge from the sun 340W Solar unit. So 340kw is probably a typo.

[JasonBModerator @jasonb]

Further down the page they give a more realistic 340W per panel. maybe a (deliberate) typo?

[Robert Atkinson 2]

On Robert Atkinson 2 Said:

Wow, ” 340kW produced per unit”!  Thats 14 times the maximum power from a standard (100A) UK mains supply. And only £450, it’s almost unbelievable……..

On a serous note, plug in solar power are NOT LEGAL in the UK at this time (March 2026).

Robert.

It is envisaged that the rules concerning the concept of plugging a potentially live 13 amp plug top into a house domestic socket will be modified soon.

Plug-in Solar Panels UK: What the New Rules Mean for You (2026)

[VicParticipant @vic]

The concept seems to be proving very popular in Germany.

https://www.dw.com/en/boom-small-solar-devices-plugged-into-household-sockets-german-energy-transition/a-75022163

[paul1956Participant @paul1956]

It is envisaged that the rules concerning the concept of plugging a potentially live 13 amp plug top into a house domestic socket will be modified soon.

From what I’ve read; These panels will never offer mains power on an exposed pin. They will only generate power when they are plugged into a live mains supply.
Firstly that prevents a ‘dead’ circuit being energised which would be dangerous if being worked on.
Secondly the invertor for the panel will need to lock it’s output frequency to that of the mains before sending any power.

So they won’t be any use as back ups for power cuts by themselves.

[paul1956]

On paul1956 Said:

It is envisaged that the rules concerning the concept of plugging a potentially live 13 amp plug top into a house domestic socket will be modified soon.

 

So they won’t be any use as back ups for power cuts by themselves.

Especially at night 🤣😅😂

I wouldn’t expect they would be unless linked to a battery storage system?

I saw a YouTube video some time ago, Robert Llewelyn has lots of solar panels at his property, and also had a Tesla Powerwall battery (now two) and he couldn’t originally use it for backup power until he had some additional equipment and rewiring.

 

[Roderick JenkinsParticipant @roderickjenkins93242]

It’s called islanding.  Google explains it succinctly:

“Solar islanding occurs when a grid-tied solar system continues to power a local circuit during a utility outage, creating a dangerous “isolated island.” Anti-islanding protection is mandated to immediately shut down inverters during outages to protect workers and equipment, though intentional, safe islanding is possible with specialized battery-backed hybrid systems.
Key Aspects of Solar Islanding
The Danger (Unintentional Islanding): When the utility grid goes down, solar inverters might fail to detect the loss of power immediately, continuing to push electricity into the grid. This creates a severe risk of electrocution for utility workers who believe the lines are de-energized.
The Solution (Anti-Islanding): Solar inverters are legally required to have anti-islanding mechanisms. These monitor voltage, frequency, or impedance to detect grid failure and disconnect the inverter within seconds.
Intentional Islanding (Backup Mode): With a hybrid inverter and battery storage, a system can legally break connection with the main grid and operate in “Island Mode” (or EPS mode). This provides power to the home while safely isolating it, preventing energy from feeding back to the grid.
System Requirements for Intentional Islanding: To operate in island mode, the system usually requires a manual or automatic transfer switch and a dedicated earthing arrangement.”

Rod

 

[howardbParticipant @howardb]

A friend over here in France tried one of these “plug in solar” kits a couple of years ago thinking it would reduce his domestic electricity bills. I think it’s output was 100 to 300 watts.

I did warn him about the necessity of ensuring that the plug might be live and to keep his fingers away from it while plugging it in.

However, his results with it weren’t great and then the inverter failed and would cost more that the whole thing was worth to replace, so he gave up on the idea.

He is now going to use the two solar panels to charge a lithium powerbank which accepts 12 volt charging, and includes an inverter, to power up his small caravan.

[not done it yetParticipant @notdoneityet]

The obvious problem, with plugging in, is that the item is beyond the circuit fuse.

Adding huge amount of power beyond the fuse could mean the circuit wiring could be loaded with its full power (through the fuse) plus the extra power injected beyond the fuse!

The current requirements are that the solar generation is fed to the consumer panel and then distributed, to wherever needed, through circuit protection fuses.

[NealebParticipant @nealeb]

I’ve been looking at solar panel plus battery systems recently. I live in a rural area with overhead cables feeding this little group of houses so power cuts in bad weather are always a possibility and one of my requirements is the ability to power the house independently. Ok, maybe no high-consumption cooking but running central heating, keep PC and phones live, etc, would be good. I’m told I need a “gateway” box between incoming mains and my own system which I presume does the power-present, grid-disconnect stuff. I’m still not quite sure how the inverter and power control electronics handle frequency sync and pushing power back up the lines. But then, my background is electronic and not electrical engineering and this power stuff and anything over 12V is beyond me…

[BazyleParticipant @bazyle]

These ‘instant’ solutions are bound to be very bad value for money and expensive if not impossible to repair in two years let alone ten.
Do the maths. Excluding fridge and heating and all day TV you perhaps use 2KWh per day, hopefully less. (modem, alarm, laptop, radio, LED lights).
Battery only you could charge on cheap rate overnight and use it during the day. The difference between day and night rate might be 20p per KWh, so 40p per day saved. (to simplify ignore that some of the time is direct off night rate) Max saving is £150 per year.
If it actually lasts ten years you have to then buy a new one, so need to save at a rate of 10% ready for the new one, plus pay interest on the money for the current one at 5%, ie 15% total. (ignoring the interest on the savings to simplify). This equates to about £700. Can you buy a battery that delivers 2kWh every day for 10 years? NO. They typically quote 1000 cycles.
That is all before you get enough solar panels to deliver 2kWh/day in winter.

[howardbParticipant @howardb]

You need to decide whether or not you want to get involved with the cost and complication of what is called a “grid tied” system.

If you just want a simple “off grid” system used as a manually or automatically switched emergency power supply using solar panel + battery + inverter it will be simpler and cheaper.

IE – The solar panel charges the battery through a charge controller,  the inverter 12 volt input is connected across the battery and it’s 230 volt ac output is switched to the house safely via a changeover switch.

https://www.grid-neutral.co.uk/blog/selling-solar-electricity-back-to-the-grid-in-the-uk

 

 

[howardbParticipant @howardb]

“This equates to about £700. Can you buy a battery that delivers 2kWh every day for 10 years? NO. They typically quote 1000 cycles”

 

10 year/ 4000 cycles warranty

12V 230Ah LiFePO4 lithium leisure battery

Built in cell balancer

Will run a 2500 watt inverter

€746.90 inc vat (in euros) in sterling ~ £ 649.47

https://www.12voltplanet.co.uk/fogstar-drift-seat-base-12v-230ah-lithium-leisure-battery-with-active-balancer.html

A decent reliable supplier – I’ve dealt with them.

[BazyleParticipant @bazyle]

Interesting link Howard. Thanks.

[Nigel Graham 2Participant @nigelgraham2]

Apart from the purely technical problems, any attempt to use some sort of power-supply merely plugged into the mains could invalidate your home insurance due to the shock and fire hazards.

[vic neweyParticipant @vicnewey60017]

Would one of those power an immersion heater in my hot water tank which is currently heated by gas, or at least keep add a bit of heat during the day

[Nigel Graham 2]

On Nigel Graham 2 Said:

Apart from the purely technical problems, any attempt to use some sort of power-supply merely plugged into the mains could invalidate your home insurance due to the shock and fire hazards.

They won’t be allowed to sell them until the regulations are updated to allow their use, so insurance shouldn’t be an issue.

If you’ve followed the thread you’d realise that there’ll be no ‘shock’ risk as the panel will need to check for mains input and match frequency before allowing any output to the connected circuit.

The should be safer than an electric iron or fire.

[vic newey]

On vic newey Said:

Would one of those power an immersion heater in my hot water tank which is currently heated by gas, or at least keep add a bit of heat during the day

Not really – a single panel outputs around 300W, whereas an immersion heater is nearer 3kW. But maybe you can plug in several of them?

[Mark RandParticipant @markrand96270]

It would be nice if some folk bothered to read the specs.

340Wp. Estimated 340kWh/per year in the midlands (which is a reasonable and common approximation). 20 year warranty. integrated grid-tied inverter.

The price is unattractive, but is roughly comparable with roof mounted plus inverter plus installation.

Government plans to make the concept legal ‘within months‘.

[paul1956]

On paul1956 Said:

On Nigel Graham 2 Said:

Apart from the purely technical problems, any attempt to use some sort of power-supply merely plugged into the mains could invalidate your home insurance due to the shock and fire hazards.

They won’t be allowed to sell them until the regulations are updated to allow their use, so insurance shouldn’t be an issue.

If you’ve followed the thread you’d realise that there’ll be no ‘shock’ risk as the panel will need to check for mains input and match frequency before allowing any output to the connected circuit.

The should be safer than an electric iron or fire.

Not really – to me, relying on some inevitably chinese electronics in the solar panel inverter to render the bare live pin of the UK plug top at zero potential prior to it being inserted in the live socket to feed the house electrics is a risk.

Electricity is not nicknamed “electrickery” for no reason !!

[Mark RandParticipant @markrand96270]

You think that a country of 1.4 billion people, with the world’s largest GDP (PPP basis), that makes almost all of the consumer electronics that we use, suddenly can’t make a safe grid tied inverter, when they’ve been making ones approved for UK, EU and US installation for a couple of decades?

[Robert Atkinson 2Participant @robertatkinson2]

I did read the datasheet. It’s pretty useless but does not repeat the kW error on the main page.
Their example sums are pretty suspect too:

“Over the course of a year the Solar Unit generated over 300kWh of energy and reduced the electricity bill for the property by nearly £100 for the year”
That equates to 33p per kWh but the energy cap is 25p per  kWh.
It also indicates a completly unshaded location.

Even under the proposed new rules these units would not be approved as they ues an internal inverter and can be daisy-chained.
They do have a patent but it’s for a floating support and some of the claims are a bit odd. https://www.search-for-intellectual-property.service.gov.uk/GB2617582/documents

There is no mention anywhere of conformity to any regulation or standard that I can find.

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