Can this be done ?

[Two on Tour]

Our van lives at home and on a sunny day like today our lithium hab battery has been topped up and full for a few hours and now the output from our 400watts of solar on our van roof is going to waste, so my question is, can I switch on my inverter and plug it into a 13amp wall outlet in our house/garage and use the output from our inverter/solar to help feed our 240v house usage ?

 

[eddie]

Yes, but:-

The national grid would blow your van up

Also you’d have to have a 13 amp plug live at the end of the connecting lead

Safer is to use an extension lead plugged into the camper, with the outlet available in the house as a dedicated socket

There are ways of doing it, automatic switch over etc but not advisable given 2024 rules and regs

 

[VXman]

Safer is to use an extension lead plugged into the camper, with the outlet available in the house as a dedicated socket

This - use it for specific purposes, hoovering, electric kettle, charging devices etc

 

[Two on Tour]

Yes, but:-

The national grid would blow your van up

Also you’d have to have a 13 amp plug live at the end of the connecting lead

Safer is to use an extension lead plugged into the camper, with the outlet available in the house as a dedicated socket

There are ways of doing it, automatic switch over etc but not advisable given 2024 rules and regs

Not doubting you Eddie, but I like to have an understanding of things and the why's, could put a bit more meat on your "The national grid would blow your van up" please.

P.S. our inverter is a stand alone, not connected into our van's 240 system.

 

[pappajohn]

Full house electric.
You'll pop the inverter due to overload.
Even plugging in a kettle will overload a 3kw inverter if ANYTHING else is plugged in/turned on.
Your battery won't last long either before being drained.
A 3kw inverter will pull around 250amps per hour at full power.

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[Tombola]

I used to have mine running the big American style fridge and microwave or kettle via a couple of sockets in the kitchen that I just trail the 240v extension from the vans inverter too.
I hardly ever remember to do it now though.

 

[Two on Tour]

Full house electric.
You'll pop the inverter due to overload.
Even plugging in a kettle will overload a 3kw inverter if ANYTHING else is plugged in/turned on.
Your battery won't last long either before being drained.
A 3kw inverter will pull around 250amps per hour at full power.

So why would all the house loads be taken from the inverter as you are implying and not shared with the input from the grid?

 

[Reallyretired]

The important difference is that to feed into the mains the inverter must be be synchronised with the AC waveform of the grid. This is a special type of inverter and what you are suggesting would be highly dangerous.
Just run an extension from you inverter to run a couple of appliances in your house, freezers and fridges would be a good choice.

 

[pappajohn]

I do this during power cuts but I use a generator.
BUT, the first thing to do is turn off the mains main switch.
That way, if the power is restored it's still isolated from the generator.
The reason for isolating......mains electric is a waveform, it alternates between positive and negative 60 times a second.
If the generator or inverter waveform doesn't EXACTLY match that of the mains wave it will damage the electronics and trip the mains fusebox

 

[Two on Tour]

My interest was sparked by a conversation I had with Tinker2 this morning and then seeing this on eBay.

1600w 240v Home DIY Plug-In Solar Power Kit Ground Mount Garden / Patio / Roof | eBay

Maximum input power: 1600W. HOYMILES 1600W MC4 integrated Microinverter 230 & 400VAC. Simply mount the panel, plug in the inverter, mount at your convenience and plug into a wall socket. All G98/1 approved with no need for approved electrician to sign off.

www.ebay.co.uk

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[Speve]

I do this during power cuts but I use a generator.
BUT, the first thing to do is turn off the mains main switch.
That way, if the power is restored it's still isolated from the generator.
The reason for isolating......mains electric is a waveform, it alternates between positive and negative 60 times a second.
If the generator or inverter waveform doesn't EXACTLY match that of the mains wave it will damage the electronics and trip the mains fusebox

So we have a victron Multiplus that compensates for mains low ampage when on EHU surely that is the same as connecting to your house and our van has not exploded yet

 

[bigtwin]

So we have a victron Multiplus that compensates for mains low ampage when on EHU surely that is the same as connecting to your house and our van has not exploded yet

No, because the supply being discussed is the OUTPUT from the MultiPlus. The MultiPlus monitors the INPUT supply, and synchronises the waveform that it generates and that is fed as an OUTPUT from the MultiPlus.

Connecting the OUTPUT from the MultiPlus to a mains supply in your house would, as eddie suggests, most likely end up with smoke escaping from the inverter.

Ian

 

[pappajohn]

That is a purpose made inverter specifically for that scenario, it's not a normal inverter you get on eBay.

 

[eddie]

Not doubting you Eddie, but I like to have an understanding of things and the why's, could put a bit more meat on your "The national grid would blow your van up" please.

P.S. our inverter is a stand alone, not connected into our van's 240 system.

OK

So apart from how would you safely connect the supply (inverter) to the load (house)?

So assume you made up a bespoke lead up to allow this, the house is connected to the national grid with a huge potential capacity and your motorhome inverter system would be connected into this, in a way your inverter is not designed to be able to cope with. At best minimal damage probably a big bang!

If you really wanted to do it you could disconnect the house from the National Grid, the at that point introduce your illegal connection lead

However, that would take longer to do that the batteries would last, unless using tiny loads, in which case, the extension lead and dedicated power point through a window is still the better option

So we have a victron Multiplus that compensates for mains low ampage when on EHU surely that is the same as connecting to your house and our van has not exploded yet

Your mains connection is on the input of the inverter, your not connecting the output of the Victron to the National Grid

 

[pappajohn]

The inverter referred to in post 10 is the same as would be on a roof solar to mains controller except the connection is via a 3 pin socket instead of a proper connection to the consumer unit.
That would work as it's designed to mirror the waveform of the mains via electronics.....cheap inverter just provide 240v, nothing more

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[Raul]

So we have a victron Multiplus that compensates for mains low ampage when on EHU surely that is the same as connecting to your house and our van has not exploded yet

Victron is a different kettle of fish, it needs to be programmed to take the grid on AC input, AND export on same AC input, via ESS assistant. Not plug and play, and when on stand alone, you have AC output, as the grid synchronisation is lost, it will run on its own hz.

 

[Raul]

My interest was sparked by a conversation I had with Tinker2 this morning and then seeing this on eBay.

1600w 240v Home DIY Plug-In Solar Power Kit Ground Mount Garden / Patio / Roof | eBay

Maximum input power: 1600W. HOYMILES 1600W MC4 integrated Microinverter 230 & 400VAC. Simply mount the panel, plug in the inverter, mount at your convenience and plug into a wall socket. All G98/1 approved with no need for approved electrician to sign off.

www.ebay.co.uk

That inv. is designed to synchronise with the grid, then produce power. But, you will back feed past your loads and meter. You need a inverter with CT clamp on mains in, to detect back feed, once your loads decrease. So that one is a big NO.

What inverter have you got?

 

[Raul]

Ppl do this with SunSynk, it’s capable to support your loads, and zero back feed, it has a CT clamp current sensor, and it knows if you pulling from the grid, and how much to compensate for your loads only, without excess going past the meter.

 

[chaser]

I have looked at using the spare electric and posted on here about it a couple of times but I am looking at using the twelve volt for something but haven't come up with anything yet.
But it seems incredible that something that will keep you going when out in the van is just left to waste it all when at home.
Our batteries are full by ten o clock on a good day all the rest of the day it just sits there switched off, just think of the amount of motorhomes and caravans there are with electric just going to waste.

 

[jezport]

I do this during power cuts but I use a generator.
BUT, the first thing to do is turn off the mains main switch.
That way, if the power is restored it's still isolated from the generator.
The reason for isolating......mains electric is a waveform, it alternates between positive and negative 60 times a second.
If the generator or inverter waveform doesn't EXACTLY match that of the mains wave it will damage the electronics and trip the mains fusebox

50hz in UK 60hz in USA

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[pappajohn]

50hz in UK 60hz in USA

Yes, my mistake, thinking of USA and always mix them up

 

[BouncyBoatFolk]

When it's sunny, and the panel has done it's work for the day I quite often plug in the cheapo inverter I have in the van and charge up my stock of AA + AAA + C +D cell rechargable batteries. I can also plug the Hitachi charger in and top up all the 18v batteries for on board drills, and tools. The emergency jump start pack gets topped up as well. Head torches get done also.
Not a lot, but the free charge makes me chuckle.
Mike.

 

[RogerIvy]

You could do this relatively easily with a Multiplus using the ESS assistant.
The Mulktiplus is a very intelligent bit of kit ... before it switches on it analyses the grid wave and syncs its wave to match the grid. In that way it can "supplement" your grid power a little when it has excess solar. So nothing blows up
You don't actually need to pass anything "through" the Multiplus. So you're not overloading anything.

... but to do this you need a Multiplus (or something equivalent), you'd need to weigh up the cost vs benefit.

 

[Two on Tour]

That inv. is designed to synchronise with the grid, then produce power. But, you will back feed past your loads and meter. You need a inverter with CT clamp on mains in, to detect back feed, once your loads decrease. So that one is a big NO.

What inverter have you got?

No intention of buying Raul, just using it as an example of a plug in to a 240 house system.

 

[Jimbohorlicks]

I have occasionally plugged in my electric kettle to reduce the full battery charge and put the boiled water in a flask for later use.
By using an extension lead you could power all sorts of home appliances

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[MisterB]

In principle it seems like a good idea to use the power BUT as has been explained, it's more complicated and potentially dangerous.
Practically though, is utilising the solar on your motorhome (via the battery and inverter) a financially viable option and just how much money would you save?
Though if it works out as a saving of £1 per day to run an extension lead into the house to use for kettle, induction hob etc, for 200 days per year, then after 2 years you could buy another lithium battery, depending on size of course.
If I was to go down that path, I would consider installing a permanent hard wired circuit, with a single dedicated socket with Automatic Transfer Switch BUT would engage a competent electrician to advise and undertake the install and doubt if the cost of the install would produce any real saving for some considerable time. Running a simple extension lead from the inverter would be a damn site more cost effective though!

Perhaps a different concept, for those with home storage batteries and an inverter capable of accepting an additional input via a generator load, would be to feed the power from the motorhome solar to that (via the motorhome inverter)? However would 200w (assumption on size of motorhome solar) really contribute that much?

None of the above is offered as a solution, just as ideas that someone might develop into a safe and viable solution.... Or someone might just dismiss it as complete hogwash !!!

 

[meanders]

The issue is as explained earlier that an inverter outputs Alternating Current (AC) being a wave modelled on a sine wave at a nominal 230Volts and around 50 -60 cycles per second (Hz), (UK and Europe mains is 50Hz, North America is 60Hz. Many inverters are not particularly good at locking the frequency that normally does not matter as most loads will tolerate a good range of frequencies and care not that the there is frequency fluctuation., hence if you look on an appliance rating plate it often says 50-60Hz. So all the time you have 12V Direct Current(DC) being converted to 230V AC then the load, there is no problem. Indeed a most electronic devices take the incoming voltage and immediately convert it back to DC at low voltage to power the device. You plug in your phone charger, and it takes the 230V AC, converts it to usually about 5.5V DC (so similar to 4 AA batteries) with some clever electronics inside the charger..

The 230V figure is a RMS figure (Root Mean Square) and relates to the actual average power of that waveform, but if you think about it going up and down, then it varies from 0V up to about 320V back down to 0V, then carries on down to -320V before returning to 0V about 50 times every second. That means if you connect at all the wrong moments in the cycle, or your cycles don't match you have a potential of 640V difference in power level that is going to warm the the inverter electronics significantly, with potentially loud bang and possibly the smoke being let out.

If you feed in to the mains with proper equipment, the invertor 'phase matches' the incoming mains, so it is generating the AC synchronised to the incoming supply. I stand to be corrected, but am fairly certain the types fitted to motorhomes do not have this 'sync' facility, nor do generators apart from the big beasts used at festivals etc. People do not realise how incredibly dangerous this can be especially if as proposed by some, you just put a 13a plug on the end and plug it into the house supply.

It's a similar issue to places with 3 phase mains which is nominally 440V (actually 3 times 230V making the maths seem a nonsense). This is made up of three circuits with the power at 120 degrees difference between the phases in the 360 cycle. This is a very efficient way of distributing power as you do not have to have a neutral and brilliant for powering large electric motors. Once split up, into different phases with neutral you still have 440V voltage difference between the phases at any one point, hence you make sure they are never mixed unless carried into the machine as a three phase supply. (A side effect of this is that your neighbours either side of you at home are likely to be on different phases, as houses are usually supplied on Phase A, then B, Then C, A, B, C, A, B, C etc to balance the phase loads. (Which is how very rarely every third house in a street will report a power failure but the others still have power.)

So to summarise, no you can't add it to your house supply with proper equipment, (or indeed to boost your 6A EHU hook up in the van) without some professionally fitted fancy 'phase matching' equipment (The sparky has to be specifically certified to make these connections to the mains), or a simpler changeover switch that will feed power to the sockets from either the mains or the invertor.

Hopefully this helps a little in explaining the complexities and hopefully in every day language. I am aware this is a simplified explanation, and the figures quoted are approximate.

 

[Steve and Denise]

Hi Paul
I have done exactly this but only to power our lights down the drive as we have quite a number of them all leds on a auto switch on,
Our van has enough solar to keep the battery topped up so I just leave the inverter on supplying my changeover switch works a treat.

 

[Coolcats]

Our van lives at home and on a sunny day like today our lithium hab battery has been topped up and full for a few hours and now the output from our 400watts of solar on our van roof is going to waste, so my question is, can I switch on my inverter and plug it into a 13amp wall outlet in our house/garage and use the output from our inverter/solar to help feed our 240v house usage ?

What you are asking is a little like the concept of EV batteries for home use.

Families could use electric vehicle batteries to power homes and save on bills as government backs new charging technologies

The government announces funding for new charging technologies, which mean families could use their electric vehicle batteries to power their homes and save on bills.

www.gov.uk

 

[LostInSpace]

can I switch on my inverter and plug it into a 13amp wall outlet in our house/garage and use the output from our inverter/solar to help feed our 240v house usage ?

If you need to ask the the answer is: NO

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